Seismic analysis response factors and design margins of piping systems
International Nuclear Information System (INIS)
Shieh, L.C.; Tsai, N.C.; Yang, M.S.; Wong, W.L.
1985-01-01
The objective of the simplified methods project of the Seismic Safety Margins Research Program is to develop a simplified seismic risk methodology for general use. The goal is to reduce seismic PRA costs to roughly 60 man-months over a 6 to 8 month period, without compromising the quality of the product. To achieve the goal, it is necessary to simplify the calculational procedure of the seismic response. The response factor approach serves this purpose. The response factor relates the median level response to the design data. Through a literature survey, we identified the various seismic analysis methods adopted in the U.S. nuclear industry for the piping system. A series of seismic response calculations was performed. The response factors and their variabilities for each method of analysis were computed. A sensitivity study of the effect of piping damping, in-structure response spectra envelop method, and analysis method was conducted. In addition, design margins, which relate the best-estimate response to the design data, are also presented
Preliminary Seismic Response and Fragility Analysis for DACS Cabinet
Energy Technology Data Exchange (ETDEWEB)
Oh, Jinho; Kwag, Shinyoung; Lee, Jongmin; Kim, Youngki [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2013-05-15
A DACS cabinet is installed in the main control room. The objective of this paper is to perform seismic analyses and evaluate the preliminary structural integrity and seismic capacity of the DACS cabinet. For this purpose, a 3-D finite element model of the DACS cabinet was developed and its modal analyses are carried out to analyze the dynamic characteristics. The response spectrum analyses and the related safety evaluation are then performed for the DACS cabinet subject to seismic loads. Finally, the seismic margin and seismic fragility of the DACS cabinet are investigated. A seismic analysis and preliminary structural integrity of the DACS cabinet under self weight and SSE load have been evaluated. For this purpose, 3-D finite element models of the DACS cabinet were developed. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. Therefore, it is concluded that the DACS cabinet was safely designed in that no damage to the preliminary structural integrity and sufficient seismic margin is expected.
Preliminary Seismic Response and Fragility Analysis for DACS Cabinet
International Nuclear Information System (INIS)
Oh, Jinho; Kwag, Shinyoung; Lee, Jongmin; Kim, Youngki
2013-01-01
A DACS cabinet is installed in the main control room. The objective of this paper is to perform seismic analyses and evaluate the preliminary structural integrity and seismic capacity of the DACS cabinet. For this purpose, a 3-D finite element model of the DACS cabinet was developed and its modal analyses are carried out to analyze the dynamic characteristics. The response spectrum analyses and the related safety evaluation are then performed for the DACS cabinet subject to seismic loads. Finally, the seismic margin and seismic fragility of the DACS cabinet are investigated. A seismic analysis and preliminary structural integrity of the DACS cabinet under self weight and SSE load have been evaluated. For this purpose, 3-D finite element models of the DACS cabinet were developed. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. A modal analysis, response spectrum analysis, and seismic fragility analysis were then performed. From the structural analysis results, the DACS cabinet is below the structural design limit of under SSE 0.3g, and can structurally withstand until less than SSE 3g based on an evaluation of the maximum effective stresses. The HCLPF capacity for the DGRS of the SSE 0.3g is 0.55g. Therefore, it is concluded that the DACS cabinet was safely designed in that no damage to the preliminary structural integrity and sufficient seismic margin is expected
Seismic Response Analysis of Continuous Multispan Bridges with Partial Isolation
Directory of Open Access Journals (Sweden)
E. Tubaldi
2015-01-01
Full Text Available Partially isolated bridges are a particular class of bridges in which isolation bearings are placed only between the piers top and the deck whereas seismic stoppers restrain the transverse motion of the deck at the abutments. This paper proposes an analytical formulation for the seismic analysis of these bridges, modelled as beams with intermediate viscoelastic restraints whose properties describe the pier-isolator behaviour. Different techniques are developed for solving the seismic problem. The first technique employs the complex mode superposition method and provides an exact benchmark solution to the problem at hand. The two other simplified techniques are based on an approximation of the displacement field and are useful for preliminary assessment and design purposes. A realistic bridge is considered as case study and its seismic response under a set of ground motion records is analyzed. First, the complex mode superposition method is applied to study the characteristic features of the dynamic and seismic response of the system. A parametric analysis is carried out to evaluate the influence of support stiffness and damping on the seismic performance. Then, a comparison is made between the exact solution and the approximate solutions in order to evaluate the accuracy and suitability of the simplified analysis techniques for evaluating the seismic response of partially isolated bridges.
Seismic response analysis for a deeply embedded nuclear power plant
International Nuclear Information System (INIS)
Chen, W.W.H.; Chatterjee, M.; Day, S.M.
1979-01-01
One of the important aspect of the aseimic design of nuclear power plants is the evaluation of the seismic soil-structure interaction effect due to design earthquakes. The soil-structure interaction effect can initiate rocking and result in different soil motions compared to the free field motions, thus significantly affecting the structural response. Two methods are generally used to solve the seismic soil-structure interaction problems: the direct finite element method (FLUSH) and the substructure or impedance approach. This paper presents the results of the horizontal seismic soil-structure interaction analysis using the impedance aproach and the direct finite element method for a deeply embedded nuclear power plant. (orig.)
Stochastic seismic floor response analysis method for various damping systems
International Nuclear Information System (INIS)
Kitada, Y.; Hattori, K.; Ogata, M.; Kanda, J.
1991-01-01
A study using the stochastic seismic response analysis method which is applicable for the estimation of floor response spectra is carried out. It is pointed out as a shortcoming in this stochastic seismic response analysis method, that the method tends to overestimate floor response spectra for low damping systems, e.g. 1% of the critical damping ratio. An investigation on the cause of the shortcoming is carried out and a number of improvements in this method were also made to the original method by taking correlation of successive peaks in a response time history into account. The application of the improved method to a typical BWR reactor building is carried out. The resultant floor response spectra are compared with those obtained by deterministic time history analysis. Floor response spectra estimated by the improved method consistently cover the response spectra obtained by the time history analysis for various damping ratios. (orig.)
Seismic Response Analysis and Design of Structure with Base Isolation
International Nuclear Information System (INIS)
Rosko, Peter
2010-01-01
The paper reports the study on seismic response and energy distribution of a multi-story civil structure. The nonlinear analysis used the 2003 Bam earthquake acceleration record as the excitation input to the structural model. The displacement response was analyzed in time domain and in frequency domain. The displacement and its derivatives result energy components. The energy distribution in each story provides useful information for the structural upgrade with help of added devices. The objective is the structural displacement response minimization. The application of the structural seismic response research is presented in base-isolation example.
Seismic response analysis of floating nuclear power plant
International Nuclear Information System (INIS)
Hagiwara, Yutaka; Nakamura, Hideharu; Shiojiri, Hiroo
1988-01-01
Since Floating Nuclear Power Plants (FNPs) are considered to be isolated from horizontal seismic motion, it is anticipated to reduce seismic load for plant components and buildings on the barge. On the other hand, barge oscillation and sloshing in the closed basin might be excited by earthquakes, because natural periods of those motions correspond to relatively-long period component (between 2 and 20 seconds) of seismic motion. Therefore, it is necessary to evaluate seismic isolation effects and barge oscillation, for the rational design of FNPs. However, there do not exist any reasonable analytical tools which can evaluate seismic response of floating structures in closed basin. The purpose of the present report is to develop a seismic analysis method for FNPs. The proposed method is based on the finite element method, and the formulation includes fluid-structure interaction, water surface wave, buoyancy effect, and non-linear characteristics of mooring system. Response analysis can be executed in both time-domain and frequency-domain. Shaking table tests were conducted to validate the proposed method of analysis. The test results showed significant isolation effect of floating structure, and apparent interaction between the barge and the basin. And 2-D and 3-D frequency domain analyses and the 2-D linear and non-linear time-domain analyses were done and those analyses could simulate the test results well. (author)
Seismic structural response analysis for multiple support excitation
International Nuclear Information System (INIS)
Shaw, D.E.
1975-01-01
In the seismic analysis of nuclear power plant equipment such as piping systems situations often arise in which piping systems span between adjacent structures or between different elevations in the same structure. Owing to the differences in the seismic time history response of different structures or different elevations of the same structure, the input support motion will differ for different supports. The concept of a frequency dependent participation factor and rotational response spectra accounting for phase differences between support excitations is developed by using classical equations of motion to formulate the seismic response of a structure subjected to multiple support excitation. The essence of the method lies in describing the seismic excitation of a multiply excited structure in terms of translational and rotational spectra used at every support and a frequency dependent spatial distribution function derived from the phase relationships of the different support time histories. In this manner it is shown that frequency dependent participation factors can be derived from the frequency dependent distribution functions. Examples are shown and discussed relative to closed form solutions and the state-of-the-art techniques presently being used for the solution of problems of multiply excited structures
Subsystem response analysis for the Seismic Safety Margins Research Program
International Nuclear Information System (INIS)
Chuang, T.Y.
1981-01-01
A review of the state-of-the-art of seismic qualification methods of subsystem has been completed. This task assesses the accuracy of seismic analysis techniques to predict dynamic response, and also identifies and quantifies sources of random and modeling undertainty in subsystem response determination. The subsystem has been classified as two categories according to the nature of support: multiply supported subsystems (e.g., piping systems) and singly supported subsystems (e.g., pumps, turbines, electrical control panels, etc.). The mutliply supported piping systems are analyzed by multisupport input time history method. The input motions are the responses of major structures. The dynamic models of the subsystems identified by the event/fault tree are created. The responses calculated by multisupport input time history method are consistent with the fragility parameters. These responses are also coordinated with the event/fault tree description. The subsystem responses are then evaluated against the fragility curves of components and systems and incorporated in the event/fault tree analysis. (orig./HP)
Seismic Response Analysis of Assembled Reactor Vessel Internals
International Nuclear Information System (INIS)
Je, Sang-Yun; Chang, Yoon-Suk; Kang, Sung-Sik
2015-01-01
RVIs (Reactor Vessel Internals) perform important safe-related functions such as upholding the nuclear fuel assembly as well as providing the coolant passage of the reactor core and supporting the control rod drive mechanism. Therefore, the components including RVIs have to be designed and constructed taking into account the structural integrity under various accident scenarios. The reliable seismic analysis is essentially demanded to maintain the safe-related functions of RVIs. In this study, a modal analysis was performed based on the previous researches to examine values of frequencies, mode shapes and participation factors. Subsequently, the structural integrity respecting to the earthquake was evaluated through a response spectrum analysis by using the output variables of modal analysis. In this study, the structural integrity of the assembled RVIs was carried out against the seismic event via the modal and response spectrum analyses. Even though 287MPa of the maximum stress value occurred at the connected region between UGS and CSA, which was lower than its allowable value. At present, fluid-structure interaction effects are being examined for further realistic simulation, which will be reported in the near future
Analysis of piping system response to seismic excitations
International Nuclear Information System (INIS)
Wang, C.Y.
1987-01-01
This paper describes a numerical algorithm for analyzing piping system response to seismic excitations. The numerical model of the piping considers hoop, flexural, axial, and torsional modes of deformation. Hoop modes generated from internal hydrodynamic loading are superimposed on the bending and twisting modes by two extra degrees of freedom. A time-history analysis technique using the implicit temporal integration scheme is addressed. The time integrator uses a predictor-corrector successive iterative scheme which satisfies the equation of motion. Both geometrical and material nonlinearities are considered. Multiple support excitations, fluid effect, piping insulation, and material dampings can be included in the analysis. Two problems are presented to illustrate the method. The results are discussed in detail
Analysis of large concrete storage tank under seismic response
Energy Technology Data Exchange (ETDEWEB)
Le, Jingyuan; Cui, Hongcheng; He, Qiang; Ju, Jinsan [China Agricultural University, Beijing (China); You, Xiaochuan [Tsinghua University, Beijing (China)
2015-01-15
This study adopted the finite element software ABAQUS to trace the dynamic response history of large reinforced concrete storage tank during different seismic excitations. The dynamic characteristics and failure modes of the tank's structure were investigated by considering the rebar's effect. Calculation results show that the large concrete storage tank remains in safe working conditions under a seismic acceleration of 55 cm/s{sup 2}. The joint of the concrete wall and dome begins to crack when seismic acceleration reaches 250 cm/s{sup 2}. As the earthquake continues, cracks spread until the top of the wall completely fails and stops working. The maximum displacement of the concrete tank and seismic acceleration are in proportion. Peak displacement and stress of the tank always appear behind the maximum acceleration.
Seismic response analysis with liquid-structure interaction
International Nuclear Information System (INIS)
Thomas, R.G.; Harrop, L.P.
1983-06-01
A linear transient finite element stress analysis of a water filled tank has been carried out using the proprietary computer code ANSYS. The containment structure was represented as rigidly fixed to ground. The flexibility of the tank wall was modelled together with the hydrostatic and hydrodynamic effects of the water contents and attached concentrated masses. The foundations were considered to be laid in solid rock, and no soil-structure interaction effects were included. The seismic input was a ground response spectrum conservatively representing both the Temblor and Parkfield modified time history records. It was found that the response of the structure was greatest at the front end (furthest from the point at which the tank is connected to a rigid internal structure), and that this was dominated by the fundamental mode. Higher modes are important at the back end. Buckling at the front end of the tank has been identified as a potential failure mechanism, and attention has also been called to the tensile capacity of the wall to base junction in this region. The requirement for a proper criterion against which to assess the margin against plastic collapse in a safe shutdown analysis has been noted. In certain regions the structure does not shake-down under the repeated reversed cyclic loading, and the need for an assessment of the implications of this for fatigue resistance has been indicated. (author)
Directory of Open Access Journals (Sweden)
Ahmer Ali
2017-06-01
Full Text Available Due to the severe impacts of recent earthquakes, the use of seismic isolation is paramount for the safety of nuclear structures. The diversity observed in seismic events demands ongoing research to analyze the devastating attributes involved, and hence to enhance the sustainability of base-isolated nuclear power plants. This study reports the seismic performance of a seismically-isolated nuclear reactor containment building (NRCB under strong short-period ground motions (SPGMs and long-period ground motions (LPGMs. The United States Nuclear Regulatory Commission-based design response spectrum for the seismic design of nuclear power plants is stipulated as the reference spectrum for ground motion selection. Within the period range(s of interest, the spectral matching of selected records with the target spectrum is ensured using the spectral-compatibility approach. NRC-compliant SPGMs and LPGMs from the mega-thrust Tohoku earthquake are used to obtain the structural response of the base-isolated NRCB. To account for the lack of earthquakes in low-to-moderate seismicity zones and the gap in the artificial synthesis of long-period records, wavelet-decomposition based autoregressive moving average modeling for artificial generation of real ground motions is performed. Based on analysis results from real and simulated SPGMs versus LPGMs, the performance of NRCBs is discussed with suggestions for future research and seismic provisions.
Energy Technology Data Exchange (ETDEWEB)
Ali, Ahmer [ENVICO Consultants Co. Ltd., Seoul (Korea, Republic of); Abu-Hayah, Nadin; Kim, Doo Kie [Civil and Environmental Engineering, Kunsan National University, Gunsan (Korea, Republic of); Cho, Sung Gook [Innose Tech Co., Ltd., Incheon (Korea, Republic of)
2017-06-15
Due to the severe impacts of recent earthquakes, the use of seismic isolation is paramount for the safety of nuclear structures. The diversity observed in seismic events demands ongoing research to analyze the devastating attributes involved, and hence to enhance the sustainability of base-isolated nuclear power plants. This study reports the seismic performance of a seismically-isolated nuclear reactor containment building (NRCB) under strong short-period ground motions (SPGMs) and long-period ground motions (LPGMs). The United States Nuclear Regulatory Commission-based design response spectrum for the seismic design of nuclear power plants is stipulated as the reference spectrum for ground motion selection. Within the period range(s) of interest, the spectral matching of selected records with the target spectrum is ensured using the spectral-compatibility approach. NRC-compliant SPGMs and LPGMs from the mega-thrust Tohoku earthquake are used to obtain the structural response of the base-isolated NRCB. To account for the lack of earthquakes in low-to-moderate seismicity zones and the gap in the artificial synthesis of long-period records, wavelet-decomposition based autoregressive moving average modeling for artificial generation of real ground motions is performed. Based on analysis results from real and simulated SPGMs versus LPGMs, the performance of NRCBs is discussed with suggestions for future research and seismic provisions.
Analysis of the seismic response of a fast reactor core
International Nuclear Information System (INIS)
Martelli, A.; Maresca, G.
1984-01-01
This report deals with the methods to apply for a correct evaluation of the reactor core seismic response. Reference is made to up-to-date design data concerning the PEC core, taking into account the presence of the core-restraint plate located close to the PEC core elements top and applying the optimized iterative procedure between the vessel linear calculation and the non-linear ones limited to the core, which had been described in a previous report. It is demonstrated that the convergence of this procedure is very fast, similar to what obtained in the calculations of the cited report, carried out with preliminary data, and it is shown that the cited methods allow a reliable evaluation of the excitation time histories for the experimental tests in support of the seismic verification of the shutdown system and the core of a fast reactor, as well as relevant data for the experimental, structural and functional, verification of the core elements in the case of seismic loads
International Nuclear Information System (INIS)
Boaga, J; Vignoli, G; Cassiani, G
2011-01-01
Inversion is a critical step in all geophysical techniques, and is generally fraught with ill-posedness. In the case of seismic surface wave studies, the inverse problem can lead to different equivalent subsoil models and consequently to different local seismic response analyses. This can have a large impact on an earthquake engineering design. In this paper, we discuss the consequences of non-uniqueness of surface wave inversion on seismic responses, with both numerical and experimental data. Our goal is to evaluate the consequences on common seismic response analysis in the case of different impedance contrast conditions. We verify the implications of inversion uncertainty, and consequently of data information content, on realistic local site responses. A stochastic process is used to generate a set of 1D shear wave velocity profiles from several specific subsurface models. All these profiles are characterized as being equivalent, i.e. their responses, in terms of a dispersion curve, are compatible with the uncertainty in the same surface wave data. The generated 1D shear velocity models are then subjected to a conventional one-dimensional seismic ground response analysis using a realistic input motion. While recent analyses claim that the consequences of surface wave inversion uncertainties are very limited, our test points out that a relationship exists between inversion confidence and seismic responses in different subsoils. In the case of regular and relatively smooth increase of shear wave velocities with depth, as is usual in sedimentary plains, our results show that the choice of a specific model among equivalent solutions strongly influences the seismic response. On the other hand, when the shallow subsoil is characterized by a strong impedance contrast (thus revealing a characteristic soil resonance period), as is common in the presence of a shallow bedrock, equivalent solutions provide practically the same seismic amplification, especially in the
Response spectrum analysis of a stochastic seismic model
International Nuclear Information System (INIS)
Kimura, Koji; Sakata, Masaru; Takemoto, Shinichiro.
1990-01-01
The stochastic response spectrum approach is presented for predicting the dynamic behavior of structures to earthquake excitation expressed by a random process, one of whose sample functions can be regarded as a recorded strong-motion earthquake accelerogram. The approach consists of modeling recorded ground motion by a random process and the root-mean-square response (rms) analysis of a single-degree-of-freedom system by using the moment equations method. The stochastic response spectrum is obtained as a plot of the maximum rms response versus the natural period of the system and is compared with the conventional response spectrum. (author)
Analysis of Bi-directional Effects on the Response of a Seismic Base Isolation System
International Nuclear Information System (INIS)
Park, Hyung-Kui; Kim, Jung-Han; Kim, Min Kyu; Choi, In-Kil
2014-01-01
The floor response spectrum depends on the height of the floor of the structure. Also FRS depends on the characteristics of the seismic base isolation system such as the natural frequency, damping ratio. In the previous study, the floor response spectrum of the base isolated structure was calculated for each axis without considering bi-directional effect. However, the shear behavior of the seismic base isolation system of two horizontal directions are correlated each other by the bi-directional effects. If the shear behavior of the seismic isolation system changes, it can influence the floor response spectrum and displacement response of isolators. In this study, the analysis of a bi-directional effect on the floor response spectrum was performed. In this study, the response of the seismic base isolation system based on the bi-directional effects was analyzed. By analyzing the time history result, while there is no alteration in the maximum shear force of seismic base isolation system, it is confirmed that the shear force is generally more decreased in a one-directional that in a two-directional in most parts. Due to the overall decreased shear force, the floor response spectrum is more reduced in a two-directional than in a one-directional
Response spectrum analysis of coupled structural response to a three component seismic disturbance
International Nuclear Information System (INIS)
Boulet, J.A.M.; Carley, T.G.
1977-01-01
The work discussed herein is a comparison and evaluation of several response spectrum analysis (RSA) techniques as applied to the same structural model with seismic excitation having three spatial components. Lagrange's equations of motion for the system were written in matrix form and uncoupled with the modal matrix. Numerical integration (fourth order Runge-Kutta) of the resulting model equations produced time histories of system displacements in response to simultaneous application of three orthogonal components of ground motion, and displacement response spectra for each modal coordinate in response to each of the three ground motion components. Five different RSA techniques were used to combine the spectral displacements and the modal matrix to give approximations of maximum system displacements. These approximations were then compared with the maximum system displacements taken from the time histories. The RSA techniques used are the method of absolute sums, the square root of the sum of the squares, the double sum approach, the method of closely spaced modes, and Lin's method. The vectors of maximum system displacements as computed by the time history analysis and the five response spectrum analysis methods are presented. (Auth.)
Seismic response analysis of structural system subjected to multiple support excitation
International Nuclear Information System (INIS)
Wu, R.W.; Hussain, F.A.; Liu, L.K.
1978-01-01
In the seismic analysis of a multiply supported structural system subjected to nonuniform excitations at each support point, the single response spectrum, the time history, and the multiple response spectrum are the three commonly employed methods. In the present paper the three methods are developed, evaluated, and the limitations and advantages of each method assessed. A numerical example has been carried out for a typical piping system. Considerably smaller responses have been predicted by the time history method than that by the single response spectrum method. This is mainly due to the fact that the phase and amplitude relations between the support excitations are faithfully retained in the time history method. The multiple response spectrum prediction has been observed to compare favourably with the time history method prediction. Based on the present evaluation, the multiple response spectrum method is the most efficient method for seismic response analysis of structural systems subjected to multiple support excitation. (Auth.)
Liang, Fayun; Chen, Haibing; Huang, Maosong
2017-07-01
To provide appropriate uses of nonlinear ground response analysis for engineering practice, a three-dimensional soil column with a distributed mass system and a time domain numerical analysis were implemented on the OpenSees simulation platform. The standard mesh of a three-dimensional soil column was suggested to be satisfied with the specified maximum frequency. The layered soil column was divided into multiple sub-soils with a different viscous damping matrix according to the shear velocities as the soil properties were significantly different. It was necessary to use a combination of other one-dimensional or three-dimensional nonlinear seismic ground analysis programs to confirm the applicability of nonlinear seismic ground motion response analysis procedures in soft soil or for strong earthquakes. The accuracy of the three-dimensional soil column finite element method was verified by dynamic centrifuge model testing under different peak accelerations of the earthquake. As a result, nonlinear seismic ground motion response analysis procedures were improved in this study. The accuracy and efficiency of the three-dimensional seismic ground response analysis can be adapted to the requirements of engineering practice.
Seismic response analysis of an instrumented building structure
Li, H.-J.; Zhu, S.-Y.; Celebi, M.
2003-01-01
The Sheraton - Universal hotel, an instrumented building lying in North Hollywood, USA is selected for case study in this paper. The finite element method is used to produce a linear time - invariant structural model, and the SAP2000 program is employed for the time history analysis of the instrumented structure under the base excitation of strong motions recorded in the basement during the Northridge, California earthquake of 17 January 1994. The calculated structural responses are compared with the recorded data in both time domain and frequency domain, and the effects of structural parameters evaluation and indeterminate factors are discussed. Some features of structural response, such as the reason why the peak responses of acceleration in the ninth floor are larger than those in the sixteenth floor, are also explained.
Seismic response analysis of column supported natural draught cooling tower shells
International Nuclear Information System (INIS)
Ramanjaneyulu, K.; Gopalakrishnan, S.; Appa Rao, T.V.S.R.
2003-01-01
Natural draught cooling towers (NDCTs) belong to the category of large civil engineering structures and are commonly used in nuclear or thermal power plants. Detailed dynamic analysis has to be carried out for design of cooling towers subjected to seismic excitation, considering the flexibility of the columns. Finite ring element formulations for dynamic analysis of cooling tower shell subjected to seismic excitation are presented in this paper. The geometry of a typical tall natural draught cooling tower is considered in this study for carrying out investigations. Transient response of the hyperbolic cooling tower shell subjected to earthquake loading has been analysed by direct time integration using acceleration-time history of North-South component of El-Centro earthquake. Parametric studies have also been carried out to study the influence of flexibility of column supports and damping on the seismic response of cooling tower shell and the results are discussed in the paper. (author)
Seismic response analysis of the deep saturated soil deposits in Shanghai
Huang, Yu; Ye, Weimin; Chen, Zhuchang
2009-01-01
The quaternary deposits in Shanghai are horizontal soil layers of thickness up to about 280 m in the urban area with an annual groundwater table between 0.5 and 0.7 m from the surface. The characteristics of deep saturated deposits may have important influences upon seismic response of the ground in Shanghai. Based on the Biot theory for porous media, the water-saturated soil deposits are modeled as a two-phase porous system consisting of solid and fluid phases, in this paper. A nonlinear constitutive model for predicting the seismic response of the ground is developed to describe the dynamic characters of the deep-saturated soil deposits in Shanghai. Subsequently, the seismic response of a typical site with 280 m deep soil layers, which is subjected to four base excitations (El Centro, Taft, Sunan, and Tangshan earthquakes), is analyzed in terms of an effective stress-based finite element method with the proposed constitutive model. Special emphasis is given to the computed results of accelerations, excess pore-water pressures, and settlements during the seismic excitations. It has been found that the analysis can capture fundamental aspects of the ground response and produce preliminary results for seismic assessment.
Seismic isolation - efficient procedure for seismic response assessement
International Nuclear Information System (INIS)
Zamfir, M. A.; Androne, M.
2016-01-01
The aim of this analysis is to reduce the dynamic response of a structure. The seismic isolation solution must take into consideration the specific site ground motion. In this paper will be presented results obtained by applying the seismic isolation method. Based on the obtained results, important conclusions can be outlined: the seismic isolation device has the ability to reduce seismic acceleration of the seismic isolated structure to values that no longer present a danger to people and environment; the seismic isolation solution is limiting devices deformations to safety values for ensuring structural integrity and stability of the entire system; the effective seismic energy dissipation and with no side effects both for the seismic isolated building and for the devices used, and the return to the initial position before earthquake occurence are obtained with acceptable permanent displacement. (authors)
Seismic response analysis of Wolsung NPP structure and equipment subjected to scenario earthquakes
Energy Technology Data Exchange (ETDEWEB)
Choi, In Kil; Ahn, Seong Moon; Choun, Young Sun; Seo, Jeong Moon
2005-03-15
The standard response spectrum proposed by US NRC has been used as a design earthquake for the design of Korean nuclear power plant structures. However, it does not reflect the characteristic of seismological and geological of Korea. In this study, the seismic response analysis of Wolsung NPP structure and equipment were performed. Three types of input motions, artificial time histories that envelop the US NRC Regulatory Guide 1.60 spectrum and the probability based scenario earthquake spectra developed for the Korean NPP site and a typical near-fault earthquake recorded at thirty sites, were used as input motions. The acceleration, displacement and shear force responses of Wolsung containment structure due to the design earthquake were larger than those due to the other input earthquakes. But, considering displacement response increases abruptly as Wolsung NPP structure does nonlinear behavior, the reassessment of the seismic safety margin based on the displacement is necessary if the structure does nonlinear behavior; although it has adequate the seismic safety margin within elastic limit. Among the main safety-related devices, electrical cabinet and pump showed the large responses on the scenario earthquake which has the high frequency characteristic. This has great effects of the seismic capacity of the main devices installed inside of the building. This means that the design earthquake is not so conservative for the safety of the safety related nuclear power plant equipments.
Seismic response analysis of Wolsung NPP structure and equipment subjected to scenario earthquakes
International Nuclear Information System (INIS)
Choi, In Kil; Ahn, Seong Moon; Choun, Young Sun; Seo, Jeong Moon
2005-03-01
The standard response spectrum proposed by US NRC has been used as a design earthquake for the design of Korean nuclear power plant structures. However, it does not reflect the characteristic of seismological and geological of Korea. In this study, the seismic response analysis of Wolsung NPP structure and equipment were performed. Three types of input motions, artificial time histories that envelop the US NRC Regulatory Guide 1.60 spectrum and the probability based scenario earthquake spectra developed for the Korean NPP site and a typical near-fault earthquake recorded at thirty sites, were used as input motions. The acceleration, displacement and shear force responses of Wolsung containment structure due to the design earthquake were larger than those due to the other input earthquakes. But, considering displacement response increases abruptly as Wolsung NPP structure does nonlinear behavior, the reassessment of the seismic safety margin based on the displacement is necessary if the structure does nonlinear behavior; although it has adequate the seismic safety margin within elastic limit. Among the main safety-related devices, electrical cabinet and pump showed the large responses on the scenario earthquake which has the high frequency characteristic. This has great effects of the seismic capacity of the main devices installed inside of the building. This means that the design earthquake is not so conservative for the safety of the safety related nuclear power plant equipments
Seismic Response Analysis of Concrete Lining Structure in Large Underground Powerhouse
Directory of Open Access Journals (Sweden)
Xiaowei Wang
2017-01-01
Full Text Available Based on the dynamic damage constitutive model of concrete material and seismic rock-lining structure interaction analysis method, the seismic response of lining structure in large underground powerhouse is studied in this paper. In order to describe strain rate dependence and fatigue damage of concrete material under cyclic loading, a dynamic constitutive model for concrete lining considering tension and shear anisotropic damage is presented, and the evolution equations of damage variables are derived. The proposed model is of simple form and can be programmed into finite element procedure easily. In order to describe seismic interaction characteristics of the surrounding rock and lining, an explicit dynamic contact analysis method considering bond and damage characteristics of contact face between the surrounding rock and lining is proposed, and this method can integrate directly without iteration. The proposed method is applied to seismic stability calculation of Yingxiuwan Underground Powerhouse, results reveal that the amplitude and duration of input seismic wave determine the damage degree of lining structure, the damage zone of lining structure is mainly distributed in its arch, and the contact face damage has great influence on the stability of the lining structure.
Incremental-hinge piping analysis methods for inelastic seismic response prediction
International Nuclear Information System (INIS)
Jaquay, K.R.; Castle, W.R.; Larson, J.E.
1989-01-01
This paper proposes nonlinear seismic response prediction methods for nuclear piping systems based on simplified plastic hinge analyses. The simplified plastic hinge analyses utilize an incremental series of flat response spectrum loadings and replace yielded components with hinge elements when a predefined hinge moment is reached. These hinge moment values, developed by Rodabaugh, result in inelastic energy dissipation of the same magnitude as observed in seismic tests of piping components. Two definitions of design level equivalent loads are employed: one conservatively based on the peaks of the design acceleration response spectra, the other based on inelastic frequencies determined by the method of Krylov and Bogolyuboff recently extended by Lazzeri to piping. Both definitions account for piping system inelastic energy dissipation using Newmark-Hall inelastic response spectrum reduction factors and the displacement ductility results of the incremental-hinge analysis. Two ratchet-fatigue damage models are used: one developed by Rodabaugh that conservatively correlates Markl static fatigue expressions to seismic tests to failure of piping components; the other developed by Severud that uses the ratchet expression of Bree for elbows and Edmunds and Beer for straights, and defines ratchet-fatigue interaction using Coffin's ductility based fatigue equation. Comparisons of predicted behavior versus experimental results are provided for a high-level seismic test of a segment of a representative nuclear plant piping system. (orig.)
Investigation and analysis of SSI effects in seismic response of NPPs EMO and EBO
International Nuclear Information System (INIS)
Juhasova, E.
1996-01-01
This progress report outlines and describes the analysis and investigations of soil-structure interaction effects in seismic response of Bohunice and Mochovce nuclear power plants. The work carries out consists of theoretical-numerical analysis of soil-structure interaction and the description of the experimental results obtained so far. Investigations were performed for different soil conditions and recommendations were elaborated as to prepare and use long-term monitoring of vibration activity at the Bohunice NPP site
Response spectrum analysis of coupled structural response to a three component seismic disturbance
International Nuclear Information System (INIS)
Boulet, J.A.M.; Carley, T.G.
1977-01-01
The work discussed herein is a comparison and evaluation of several response spectrum analysis (RSA) techniques as applied to the same structural model with seismic excitation having three spatial components. The structural model includes five lumped masses (floors) connected by four elastic members. The base is supported by three translational springs and two horizontal torsional springs. In general, the mass center and shear center of a building floor are distinct locations. Hence, inertia forces, which act at the mass center, induce twisting in the structure. Through this induced torsion, the lateral (x and y) displacements of the mass elements are coupled. The ground motion components used for this study are artificial earthquake records generated from recorded accelerograms by a spectrum modification technique. The accelerograms have response spectra which are compatible with U.S. NRC Regulatory Guide 1.60. Lagrange's equations of motion for the system were written in matrix form and uncoupled with the modal matrix. Numerical integration (fourth order Runge-Kutta) of the resulting modal equations produced time histories of system displacements in response to simultaneous application of three orthogonal components of ground motion, and displacement response spectra for each modal coordinate in response to each of the three ground motion components. Five different RSA techniques were used to combine the spectral displacements and the modal matrix to give approximations of maximum system displacements. These approximations were then compared with the maximum system displacements taken from the time histories. The RSA techniques used are the method of absolute sums, the square root of the sum of the sum of the squares, the double sum approach, the method of closely spaced modes, and Lin's method
Seismic response analysis of BWR buildings with embedded foundation
International Nuclear Information System (INIS)
Fukuzawa, R.; Chiba, O.; Tohdo, M.
1985-01-01
An investigation on the effect of various types of foundations embedded into soil deposit to the responses of BWR buildings is made. The frequency characteristics of massless rigid foundations such as impedance functions and input motion are first obtained, depending on the embedment depth, contact condition of side wall to soil and the thickness of surface layer in a two-layered soil. From the results it is found that the embedment depth and the thickness of surface layer have a distinct effect to the responses contributed by the impedance functions and the response values characterized by the input motions are obviously influenced by the embedment depth and the contact length of side wall to soil deposit. (orig.)
International Nuclear Information System (INIS)
Kokusho, T.; Nishi, K.; Okamoto, T.; Tanaka, Y.; Ueshima, T.; Kudo, K.; Kataoka, T.; Ikemi, M.; Kawai, T.; Sawada, Y.; Suzuki, K.; Yajima, K.; Higashi, S.
1997-01-01
An international joint research program called HLSST is proceeding. HLSST is large-scale seismic test (LSST) to investigate soil-structure interaction (SSI) during large earthquake in the field in Hualien, a high seismic region in Taiwan. A 1/4-scale model building was constructed on the gravelly soil in this site, and the backfill material of crushed stone was placed around the model plant after excavation for the construction. Also the model building and the foundation ground were extensively instrumental to monitor structure and ground response. To accurately evaluate SSI during earthquakes, geotechnical investigation and forced vibration test were performed during construction process namely before/after base excavation, after structure construction and after backfilling. And the distribution of the mechanical properties of the gravelly soil and the backfill are measured after the completion of the construction by penetration test and PS-logging etc. This paper describes the distribution and the change of the shear wave velocity (V s ) measured by the field test. Discussion is made on the effect of overburden pressure during the construction process on V s in the neighbouring soil and, further on the numerical soil model for SSI analysis. (orig.)
Seismic response of transamerical building. I. Data and preliminary analysis
Celebi, M.; Safak, E.
1991-01-01
The objective of this paper is to present preliminary analyses of a set of acceleration response records obtained during the October 17, 1989 Loma Prieta earthquake (Ms = 7.1) from the 60-story vertically tapered, pyramid-shaped Trans-america Building-a landmark of San Francisco. The building was instrumented in 1985 with 22 channels of synchronized sensors consisting of 13 uniaxial accelerometers deployed throughout the structure and connected to a central recording system and three triaxial strong-motion accelerographs at three different levels of the structure. No free-field accelerographs are at the site. The acceleration records permit the study of the behavior of this unique structure. The predominant translational response of the building and the associated frequency at approximately 0.28 Hz are identified from the records and their Fourier amplitude spectra. The records do not indicate any significant torsional motion. However, there is rocking type soil-structure interaction, and an associated frequency of approximately 2.0 Hz is identified from the Fourier amplitude spectra of the differential motions between the ground level and that at the basement. In addition, the response spectra for the basement motions indicate significant resonance in both directions at a period of approximately 0.5 seconds.
Seismic response analysis for hinged-leg type port crane
Energy Technology Data Exchange (ETDEWEB)
Kashiwazaki, A.; Kanayama, T.; Arai, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)
2000-04-01
Container cranes and unloaders in Kobe Pont were severely damaged during the Southern Hyogo Prefecture Earthquake in 1995. Notably, some of the hinged-leg type of cranes with hinges at the end of sea-or land-side of legs were overturned. These damages were derived from the uplifting of their legs. To explain the uplifting and overturning behavior, we carried out nonlinear analyses and shaking table tests using a 1/8-scale model of the container crane. The results of nonlinear response analyses of hinged-leg type of crane, which are in an agreement with the state of damages in the Southern Hyogo Prefecture Earthquake and the result of shaking table tests, are described. (author)
Time Analysis of Building Dynamic Response Under Seismic Action. Part 1: Theoretical Propositions
Ufimtcev, E. M.
2017-11-01
The first part of the article presents the main provisions of the analytical approach - the time analysis method (TAM) developed for the calculation of the elastic dynamic response of rod structures as discrete dissipative systems (DDS) and based on the investigation of the characteristic matrix quadratic equation. The assumptions adopted in the construction of the mathematical model of structural oscillations as well as the features of seismic forces’ calculating and recording based on the data of earthquake accelerograms are given. A system to resolve equations is given to determine the nodal (kinematic and force) response parameters as well as the stress-strain state (SSS) parameters of the system’s rods.
DRY TRANSFER FACILITY SEISMIC ANALYSIS
International Nuclear Information System (INIS)
EARNEST, S.; KO, H.; DOCKERY, W.; PERNISI, R.
2004-01-01
The purpose of this calculation is to perform a dynamic and static analysis on the Dry Transfer Facility, and to determine the response spectra seismic forces for the design basis ground motions. The resulting seismic forces and accelerations will be used in a subsequent calculation to complete preliminary design of the concrete shear walls, diaphragms, and basemat
International Nuclear Information System (INIS)
Zeuch, W.R.; Wang, C.Y.
1985-01-01
This paper presents some of the current capabilities of the three-dimensional piping code SHAPS and demonstrates their usefulness in handling analyses encountered in typical LMFBR studies. Several examples demonstrate the utility of the SHAPS code for problems involving fluid-structure interactions and seismic-related events occurring in three-dimensional piping networks. Results of two studies of pressure wave propagation demonstrate the dynamic coupling of pipes and elbows producing global motion and rigorous treatment of physical quantities such as changes in density, pressure, and strain energy. Results of the seismic analysis demonstrate the capability of SHAPS to handle dynamic structural response within a piping network over an extended transient period of several seconds. Variation in dominant stress frequencies and global translational frequencies were easily handled with the code. 4 refs., 10 figs
International Nuclear Information System (INIS)
Bhaumik, Lopamudra; Raychowdhury, Prishati
2013-01-01
Highlights: • Seismic response analysis of an internal shearwall of a reactor is done. • Incremental dynamic analysis is performed with 30 recorded ground motions. • Equivalent viscous damping increases up to twice when nonlinear SSI is considered. • Roof drift demand increases up to 25% upon consideration of foundation nonlinearity. • Base shear, base moment and ductility reduce up to 62%, 40%, and 35%, respectively. - Abstract: This study focuses on the seismic response analysis of an internal shearwall of a typical Indian reactor resting on a medium dense sandy silty soil, incorporating the nonlinear behavior of the soil-foundation interface. The modeling is done in an open-source finite element framework, OpenSees, where the soil-structure interaction (SSI) is modeled using a Beam-on-Nonlinear-Winkler-Foundation (BNWF) approach. Static pushover analysis and cyclic analysis are performed followed by an incremental dynamic analysis (IDA) with 30 recorded ground motions. For performing IDA, the spectral acceleration of each motion corresponding to the fundamental period, S a (T 1 )is incremented from 0.1 g to 1.0 g with an increment step of 0.1 g. It is observed from the cyclic analysis that the equivalent viscous damping of the system increases upto twice upon incorporation of inelastic SSI. The IDA results demonstrate that the average peak base shear, base moment and displacement ductility demand reduces as much as 62%, 40%, and 35%, respectively, whereas the roof drift demand increases up to 25% upon consideration of foundation nonlinearity for the highest intensity motion. These observations indicate the need of critical consideration of nonlinear soil-structure interaction as any deficient modeling of the same may lead to an inaccurate estimation of the seismic demands of the structure
Energy Technology Data Exchange (ETDEWEB)
Bhaumik, Lopamudra, E-mail: lbhaumi2@illinois.edu [University of Illinois at Urbana-Champaign (United States); Raychowdhury, Prishati, E-mail: prishati@iitk.ac.in [Indian Institute of Technology Kanpur (India)
2013-12-15
Highlights: • Seismic response analysis of an internal shearwall of a reactor is done. • Incremental dynamic analysis is performed with 30 recorded ground motions. • Equivalent viscous damping increases up to twice when nonlinear SSI is considered. • Roof drift demand increases up to 25% upon consideration of foundation nonlinearity. • Base shear, base moment and ductility reduce up to 62%, 40%, and 35%, respectively. - Abstract: This study focuses on the seismic response analysis of an internal shearwall of a typical Indian reactor resting on a medium dense sandy silty soil, incorporating the nonlinear behavior of the soil-foundation interface. The modeling is done in an open-source finite element framework, OpenSees, where the soil-structure interaction (SSI) is modeled using a Beam-on-Nonlinear-Winkler-Foundation (BNWF) approach. Static pushover analysis and cyclic analysis are performed followed by an incremental dynamic analysis (IDA) with 30 recorded ground motions. For performing IDA, the spectral acceleration of each motion corresponding to the fundamental period, S{sub a}(T{sub 1})is incremented from 0.1 g to 1.0 g with an increment step of 0.1 g. It is observed from the cyclic analysis that the equivalent viscous damping of the system increases upto twice upon incorporation of inelastic SSI. The IDA results demonstrate that the average peak base shear, base moment and displacement ductility demand reduces as much as 62%, 40%, and 35%, respectively, whereas the roof drift demand increases up to 25% upon consideration of foundation nonlinearity for the highest intensity motion. These observations indicate the need of critical consideration of nonlinear soil-structure interaction as any deficient modeling of the same may lead to an inaccurate estimation of the seismic demands of the structure.
Analysis and evaluation of seismic response of reactor building for Daya Bay Nuclear Power Plant
International Nuclear Information System (INIS)
Li Zhongcheng; China Guangdong Nuclear Power Company, Shenzhen; Li Zhongxian
2005-01-01
Daya Bay NPP has been operating safely and stably over 10 years since 1994, and its' seismic analysis of nuclear island was in accordance with the approaches in RCC-G standard for the model M310, in which the Simplified Impedance Matrix Method (SIMM) was employed for the consideration of SSI. Thanks to the rapid progress being made in upgrading the evaluation technology and the capability of data processing systems, methods and software tools for the SSI analysis have experienced significant development all over the world. Focused on the model of reactor building of the Daya Bay NPP, in his paper the more sophisticated 3D half-space continuum impedance method based on the Green functions is used to analyze the functions of the soil, and then the seismic responses of the coupled SSI system are calculated and compared with the corresponding design values. It demonstrates that the design method provides a set of conservatively safe results. The conclusions from the study is hopefully to provide some important references to the assessment of seismic safety margin for the operating NPPs. (authors)
International Nuclear Information System (INIS)
Iijima, Tadashi
2005-01-01
We applied improved capacity spectrum method (ICSM) to a piping system with an asymmetric load-deformation relationship in a piping elbow. The capacity spectrum method can predict an inelastic response by balancing the structural capacity obtained from the load-deformation relationship with the seismic demand defined by an acceleration-displacement response spectrum. The ICSM employs (1) effective damping ratio and period that are based on a statistical methodology, (2) practical procedures necessary to obtain a balance between the structural capacity and the seismic demand. The effective damping ratio and period are defined so as to maximize the probability that predicted response errors lie inside the -10 to 20% range. However, without taking asymmetry into consideration the displacement calculated by using the load-deformation relationship on the stiffer side was 39% larger than that of a time history analysis by a direct integral method. On the other hand, when asymmetry was taken into account, the calculated displacement was only 14% larger than that of a time history analysis. Thus, we verified that the ICSM could predict the inelastic response with errors lying within the -10 to 20% range, by taking into account the asymmetric load-deformation relationship of the piping system. (author)
Seismic Response Analysis and Test of 1/8 Scale Model for a Spent Fuel Storage Cask
Energy Technology Data Exchange (ETDEWEB)
Lee, Jae Han; Park, C. G.; Koo, G. H.; Seo, G. S. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Yeom, S. H. [Chungnam Univ., Daejeon (Korea, Republic of); Choi, B. I.; Cho, Y. D. [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)
2005-07-15
The seismic response tests of a spent fuel dry storage cask model of 1/8 scale are performed for an typical 1940 El-centro and Kobe earthquakes. This report firstly focuses on the data generation by seismic response tests of a free standing storage cask model to check the overturing possibility of a storage cask and the slipping displacement on concrete slab bed. The variations in seismic load magnitude and cask/bed interface friction are considered in tests. The test results show that the model gives an overturning response for an extreme condition only. A FEM model is built for the test model of 1/8 scale spent fuel dry storage cask using available 3D contact conditions in ABAQUS/Explicit. Input load for this analysis is El-centro earthquake, and the friction coefficients are obtained from the test result. Penalty and kinematic contact methods of ABAQUS are used for a mechanical contact formulation. The analysis methods was verified with the rocking angle obtained by seismic response tests. The kinematic contact method with an adequate normal contact stiffness showed a good agreement with tests. Based on the established analysis method for 1/8 scale model, the seismic response analyses of a full scale model are performed for design and beyond design seismic loads.
International Nuclear Information System (INIS)
Hasegawa, M.; Nakai, S.; Watanabe, T.
1985-01-01
A practical method for elasto-plastic seismic response analysis is described under considerations of nonlinear material law of a structure and dynamic soil-structure interaction. The method is essentially based on the substructure approach of time domain analysis. Verification of the present method is carried out for typical BWR-MARK II type reactor building which is embedded in a soil, and the results are compared with those of the frequency response analysis which gives good accuracy for linear system. As a result, the present method exhibits sufficient accuracy. Furthermore, elasto-plastic analyses considering the soil-structure interaction are made as an application of the present method, and nonlinear behaviors of the structure and embedment effects are discussed. (orig.)
International Nuclear Information System (INIS)
Basu, Prabir C.; Roshan, A.D.
2007-01-01
A number of shake table tests had been conducted on the scaled down model of a concrete wall as part of CAMUS experiment. The experiments were conducted between 1996 and 1998 in the CEA facilities in Saclay, France. Benchmarking of CAMUS experiments was undertaken as a part of the coordinated research program on 'Safety Significance of Near-Field Earthquakes' organised by International Atomic Energy Agency (IAEA). Technique of deflection-based method was adopted for benchmarking exercise. Non-linear static procedure of deflection-based method has two basic steps: pushover analysis, and determination of target displacement or performance point. Pushover analysis is an analytical procedure to assess the capacity to withstand seismic loading effect that a structural system can offer considering the redundancies and inelastic deformation. Outcome of a pushover analysis is the plot of force-displacement (base shear-top/roof displacement) curve of the structure. This is obtained by step-by-step non-linear static analysis of the structure with increasing value of load. The second step is to determine target displacement, which is also known as performance point. The target displacement is the likely maximum displacement of the structure due to a specified seismic input motion. Established procedures, FEMA-273 and ATC-40, are available to determine this maximum deflection. The responses of CAMUS test specimen are determined by deflection-based method and analytically calculated values compare well with the test results
International Nuclear Information System (INIS)
Surh, Han-Bum; Ryu, Tae-Young; Park, Jin-Sung; Ahn, Eun-Woo; Choi, Chul-Sun; Koo, Ja Choon; Choi, Jae-Boong; Kim, Moon Ki
2015-01-01
Highlights: • Piping system in the APR 1400 NPP with a base isolation design is studied. • Seismic response of piping system in base isolated building are investigated. • Stress classification method is examined for piping subjected to seismic loading. • Primary stress of piping is reduced due to base isolation design. • Substantial secondary stress is observed in the main steam piping. - Abstract: In this study, the stress response of the piping system in the advanced power reactor 1400 (APR 1400) with a base isolation design subjected to seismic loading is addressed. The piping system located between the auxiliary building with base isolation and the turbine building with a fixed base is considered since it can be subjected to substantial relative support movement during seismic events. First, the support responses with respect to the base characteristic are investigated to perform seismic analysis for multiple support excitations. Finite element analyses are performed to predict the piping stress response through various analysis methods such as the response spectrum, seismic support movement and time history method. To separately evaluate the inertial effect and support movement effect on the piping stress, the stress is decomposed into a primary and secondary stress using the proposed method. Finally, influences of the base isolation design on the piping system in the APR 1400 are addressed. The primary stress based on the inertial loading is effectively reduced in a base isolation design, whereas a considerable amount of secondary stress is generated in the piping system connecting a base isolated building with a fixed base building. It is also confirmed that both the response spectrum analysis and seismic support movement analysis provide more conservative estimations of the piping stress compared to the time history analysis
Yee, Eric
In this thesis I address a series of issues related to ground failure and ground motions during earthquakes. A major component is the evaluation of cyclic volumetric strain behavior of unsaturated soils, more commonly known as seismic compression, from advanced laboratory testing. Another major component is the application of nonlinear and equivalent linear ground response analyses to large-strain problems involving highly nonlinear dynamic soil behavior. These two components are merged in the analysis of a truly unique and crucial field case history of nonlinear site response and seismic compression. My first topic concerns dynamic soil testing for relatively small strain dynamic soil properties such as threshold strains, gammatv. Such testing is often conducted using specialized devices such as dual-specimen simple-shear, as devices configured for large strain testing produce noisy signals in the small strain range. Working with a simple shear device originally developed for large-strain testing, I extend its low-strain capabilities by characterizing noisy signals and utilizing several statistical methods to extract meaningful responses in the small strain range. I utilize linear regression of a transformed variable to estimate the cyclic shear strain from a noisy signal and the confidence interval on its amplitude. I utilize Kernel regression with the Nadaraya-Watson estimator and a Gaussian kernel to evaluate vertical strain response. A practical utilization of these techniques is illustrated by evaluating threshold shear strains for volume change with a procedure that takes into account uncertainties in the measured shear and vertical strains. My second topic concerns the seismic compression characteristics of non-plastic and low-plasticity silty sands with varying fines content (10 ≤ FC ≤ 60%). Simple shear testing was performed on various sand-fines mixtures at a range of modified Proctor relative compaction levels ( RC) and degrees-of-saturation (S
Seismic analysis and testing of nuclear power plants
International Nuclear Information System (INIS)
1979-01-01
The following subjects are discussed in this guide: General Recommendations for seismic classification, loading combinations and allowable limits; seismic analysis methods; implications for seismic design; seismic testing and qualification; seismic instrumentation; modelling techniques; material property characterization; seismic response of soil deposits and earth structures; liquefaction and ground failure; slope stability; sloshing effects in water pools; qualification testing by means of the transport vehicle
International Nuclear Information System (INIS)
Morrone, A.
1979-01-01
A particular type of seismic analysis performed on the Nuclear Island Buildings (NIB) complex of a nuclear power plant and the methods developed to combine torsional, rotational and translational responses are described. The NIB complex analyzed consists of various buildings supported on a common foundation mat and tied together from the underground foundation to the roof levels. Three independent building mathematical models were used for the three components of the earthquake with a lumped-mass method utilizing direct integration of the coupled equations of motion. The input ground acceleration time histories were based on three 20 s long statistically independent records whose normalized response spectra enveloped those of Regulatory Guide 1.60. A linear stochastic model was used to generate these records which simulated strong motion earthquakes. Due to site characteristics, the soil material properties were calculated considering different ranges of soil moduli below and above the foundation. (orig.)
International Nuclear Information System (INIS)
Morrone, A.; Sigal, G.B.
1979-01-01
A particular type of seismic analysis performed on the Nuclear Island Buildings (NIB) complex of a nuclear power plant and the methods developed to combine torsional, rotational and translational responses are described. The NIB complex analyzed consists of various buildings supported on a common foundation mat and tied together from the underground foundation to the roof levels. Three independent building mathematical models were used for the three components of the earthquake with a lumped-mass method utilizing direct integration of the coupled equations of motion. The input ground acceleration time histories were based on three 20 s long statistically independent records whose mormalized response spectra enveloped those of Regulatory Guide 1.60. A linear stochastic model was used to generate these records which simulated strong motion earthquakes. Due to site characteristics, the soil material properties were calculated considering different ranges of soil moduli below and above the foundation
International Nuclear Information System (INIS)
Park, Jinkyun; Kin, Yochan; Jung, Wondea; Jang, Seung Cheol
2014-01-01
This is because the PSA has been used for several decades as the representative tool to evaluate the safety of NPPs. To this end, it is inevitable to evaluate human error probabilities (HEPs) in conducting important tasks being considered in the PSA framework (i.e., HFEs; human failure events), which are able to significantly affect the safety of NPPs. In addition, it should be emphasized that the provision of a realistic human performance data is an important precondition for calculating HEPs under a seismic condition. Unfortunately, it seems that HRA methods being currently used for calculating HEPs under a seismic event do not properly consider the performance variation of human operators. For this reason, in this paper, a framework to estimate response time data that are critical for calculating HEPs is suggested with respect to a seismic intensity. This paper suggested a systematic framework for estimating response time data that would be one of the most critical for calculating HEPs. Although extensive review of existing literatures is indispensable for identifying response times of human operators who have to conduct a series of tasks prescribed in procedures based on a couple of wrong indications, it is highly expected that response time data for seismic HRA can be properly secured through revisiting response time data collected from diverse situations without concerning a seismic event
International Nuclear Information System (INIS)
Jerez, Sandra; Mebarki, Ahmed
2010-01-01
This paper develops a new modified uncoupled modal response history analysis (M-UMRHA) in order to study the seismic behavior of structures. It aims to provide an acceptable accuracy with reduced calculation duration in comparison to complete analysis, i.e. the THA. The proposed method improves the existing UMRHA, developed by Chopra and Goel [1], by considering an energy based approach to build the capacity curve [2] and a pseudo-adaptive feature to account for changes in modal shapes after yielding, motivated by an adaptive method [3]. Validation is made by comparison with NLTHA as well as other simplified methods. Low and medium-rise RC buildings were analyzed under real ground motion records. Results show good estimates of structural parameters and give good correlation between damage and story displacements as well as drifts. Like other simplified methods, accuracy decreases in the inelastic domain. However, this procedure gives acceptable estimates of structural response with a few additional calculations and it has the potential to be used in large scale studies, and probabilistic approaches.
Analysis of recorded earthquake response data at the Hualien large-scale seismic test site
International Nuclear Information System (INIS)
Hyun, C.H.; Tang, H.T.; Dermitzakis, S.; Esfandiari, S.
1997-01-01
A soil-structure interaction (SSI) experiment is being conducted in a seismically active region in Hualien, Taiwan. To obtain earthquake data for quantifying SSI effects and providing a basis to benchmark analysis methods, a 1/4-th scale cylindrical concrete containment model similar in shape to that of a nuclear power plant containment was constructed in the field where both the containment model and its surrounding soil, surface and sub-surface, are extensively instrumented to record earthquake data. In between September 1993 and May 1995, eight earthquakes with Richter magnitudes ranging from 4.2 to 6.2 were recorded. The author focuses on studying and analyzing the recorded data to provide information on the response characteristics of the Hualien soil-structure system, the SSI effects and the ground motion characteristics. An effort was also made to directly determine the site soil physical properties based on correlation analysis of the recorded data. No modeling simulations were attempted to try to analytically predict the SSI response of the soil and the structure. These will be the scope of a subsequent study
Seismic structural response analysis using consistent mass matrices having dynamic coupling
International Nuclear Information System (INIS)
Shaw, D.E.
1977-01-01
The basis for the theoretical development of this paper is the linear matrix equations of motion for an unconstrained structure subject to support excitation. The equations are formulated in terms of absolute displacement, velocity and acceleration vectors. By means of a transformation of the absolute response vectors into displacements, velocities and accelerations relative to the support motions, the homogeneous equations become non-homogeneous and the non-homogeneous boundary conditions become homogeneous with relative displacements, velocities and accelerations being zero at support points. The forcing function or inertial loading vector is shown to consist of two parts. The first part is comprised of the mass matrix times the suppport acceleration function times a vector of structural displacements resulting from a unit vector of support displacements in the direction of excitation. This inertial loading corresponds to the classical seismic loading vector and is indeed the only loading vector for lumped-mass systems. The second part of he inertial loading vectors consists of the mass matrix times the support acceleration function times a vector of structural accelerations resulting from unit support accelerations in the direction of excitation. This term is not present in classical seismic analysis formulations and results from the presence of off-diagonal terms in the mass matrices which give rise to dynamic coupling through the mass matrix. Thus, for lumped-mass models, the classical formulation of the inertial loading vector is correct. However, if dynamic coupling terms are included through off-diagonal terms in the mass matrix, an additional inertia loading vector must be considered
International Nuclear Information System (INIS)
Tajirian, F.F.
1992-01-01
The Advanced Liquid Metal Reactor (ALMR) design uses seismic isolation as a cost effective approach for simplifying seismic design of the reactor module, and for enhancing margins to handle beyond design basis earthquakes (BDBE). A comprehensive seismic analysis plan has been developed to confirm the adequacy of the design and to support regulatory licensing activities. In this plan state-of-the-art computer programs are used to evaluate the system response of the ALMR. Several factors that affect seismic response will be investigated. These include variability in the input earthquake mechanism, soil-structure interaction effects, and nonlinear response of the isolators. This paper reviews the type of analyses that are planned, and discuses the approach that will be used for validating the specific features of computer programs that are required in the analysis of isolated structures. To date, different linear and nonlinear seismic analyses have been completed. The results of recently completed linear analyses have been summarized elsewhere. The findings of three-dimensional seismic nonlinear analyses are presented in this paper. These analyses were performed to evaluate the effect of changes of isolator horizontal stiffness with horizontal displacement on overall response, to develop an approach for representing BDBE events with return periods exceeding 10,000 years, and to assess margins in the design for BDBEs. From the results of these analyses and bearing test data, it can be concluded that a properly designed and constructed seismic isolation system can accommodate displacements several times the design safe shutdown earthquake (SSE) for the ALMR. (author)
Energy Technology Data Exchange (ETDEWEB)
Kim, Joon Kyoung [Semyung Univ., Research Institute of Industrial Science and Technol , Jecheon (Korea, Republic of)
1996-12-15
Objective of this study is to investigate and develop the methodologies and corresponding computer codes, compatible to the domestic seismological and geological environments, for estimating ground response spectrum and probabilistic seismic hazard. Using the PSHA computer program, the Cumulative Probability Functions(CPDF) and Probability Functions (PDF) of the annual exceedence have been investigated for the analysis of the uncertainty space of the annual probability at ten interested seismic hazard levels (0.1 g to 0.99 g). The cumulative provability functions and provability functions of the annual exceedence have been also compared to those results from the different input parameter spaces.
International Nuclear Information System (INIS)
Ryu, Jeong-Soo; Seo, Choon-Gyo; Kim, Jae-Min; Yun, Chung-Bang
2010-01-01
This paper proposes a slightly new three-dimensional radial-shaped dynamic infinite elements fully coupled to finite elements for an analysis of soil-structure interaction system in a horizontally layered medium. We then deal with a seismic analysis technique for a three-dimensional soil-structure interactive system, based on the coupled finite-infinite method in frequency domain. The dynamic infinite elements are simulated for the unbounded domain with wave functions propagating multi-generated wave components. The accuracy of the dynamic infinite element and effectiveness of the seismic analysis technique may be demonstrated through a typical compliance analysis of square surface footing, an L-shaped mat concrete footing on layered soil medium and two kinds of practical seismic analysis tests. The practical analyses are (1) a site response analysis of the well-known Hualien site excited by all travelling wave components (primary, shear, Rayleigh waves) and (2) a generation of a floor response spectrum of a nuclear power plant. The obtained dynamic results show good agreement compared with the measured response data and numerical values of other soil-structure interaction analysis package.
Directory of Open Access Journals (Sweden)
E. Çelebi
2012-11-01
Full Text Available The objective of this paper focuses primarily on the numerical approach based on two-dimensional (2-D finite element method for analysis of the seismic response of infinite soil-structure interaction (SSI system. This study is performed by a series of different scenarios that involved comprehensive parametric analyses including the effects of realistic material properties of the underlying soil on the structural response quantities. Viscous artificial boundaries, simulating the process of wave transmission along the truncated interface of the semi-infinite space, are adopted in the non-linear finite element formulation in the time domain along with Newmark's integration. The slenderness ratio of the superstructure and the local soil conditions as well as the characteristics of input excitations are important parameters for the numerical simulation in this research. The mechanical behavior of the underlying soil medium considered in this prediction model is simulated by an undrained elasto-plastic Mohr-Coulomb model under plane-strain conditions. To emphasize the important findings of this type of problems to civil engineers, systematic calculations with different controlling parameters are accomplished to evaluate directly the structural response of the vibrating soil-structure system. When the underlying soil becomes stiffer, the frequency content of the seismic motion has a major role in altering the seismic response. The sudden increase of the dynamic response is more pronounced for resonance case, when the frequency content of the seismic ground motion is close to that of the SSI system. The SSI effects under different seismic inputs are different for all considered soil conditions and structural types.
International Nuclear Information System (INIS)
Saha, S.; Dasgupta, A.; Basu, P.C.
1993-01-01
Seismic analysis of a Reactor Building is performed idealising the system as a beam model (BM) and also an Axi-symmetric model (ASM) and the results compared. In both the cases effect of Soil-Structure Interaction have been taken Into account. Since the lower boundary of the ASM was at a depth much lower than that of the BM, deconvolution of the specified Free-Field Motion (FFM) was necessary. The deconvolution has been performed using frequency domain approach. (author)
International Nuclear Information System (INIS)
Miyagawa, Yoshinori; Sato, Hiroaki
2015-01-01
A bushing is a device for insulation and support of a conductor. Especially it is called center-clamp type when it is connected with a metal holder through clamping force. As a consequence of damage of center-clamp type bushings in Tohoku Earthquake in 2011, refinement of the response analysis method and review of the seismic design procedure became necessary. In the present report, the fiber model, which can evaluate non-linear behavior in the section subjected to axial force and bending moment, was implemented to the CRIEPI's finite element analysis program 'Mastrd' considering following characteristics of center-clamp type bushings. a) The gasket section between a porcelain tube and a metal holder has a torus shape. b) Springs around the top of the bushing give clamping force, but they lock in excessive base rotation. c) The gasket does not resist against tension. d) Local resistance against compression due to bending increases in use of very thin gaskets. The developed program was verified through comparison with the shaking table test result for real bushings whose voltage classes were 154 kV and 275 kV. Deformation indices as rotation angle and base opening due to bending were influenced by damping conditions. Though there was not the condition which brought about remarkable underestimation, reduction of damping for a fiber model element was preferable for safety. On the other hand, bending moment was consistent with experimental results because it tended not to fluctuate in the non-linear region. (author)
Seismic response analysis of a 13-story steel moment-framed building in Alhambra, California
Rodgers, Janise E.; Sanli, Ahmet K.; Çelebi, Mehmet
2004-01-01
The seismic performance of steel moment-framed buildings has been of particular interest since brittle fractures were discovered at the beam-column connections of some frames following the M6.7 1994 Northridge earthquake. This report presents an investigation of the seismic behavior of an instrumented 13-story steel moment frame building located in the greater Los Angeles area of California. An extensive strong motion dataset, ambient vibration data, engineering drawings and earthquake damage reports are available for this building. The data are described and subsequently analyzed. The results of the analyses show that the building response is more complex than would be expected from its highly symmetrical geometry. The building's response is characterized by low damping in the fundamental mode, larger peak accelerations in the intermediate stories than at the roof, extended periods of vibration after the cessation of strong input shaking, beating in the response, and significant torsion during strong shaking at the top of the concrete piers which extend from the basement to the second floor. The analyses of the data and all damage detection methods employed except one method based on system identification indicate that the response of the structure was elastic in all recorded earthquakes. These findings are in general agreement with the results of intrusive inspections (meaning fireproofing and architectural finishes were removed) conducted on approximately 5 percent of the moment connections following the Northridge earthquake, which found no earthquake damage.
Directory of Open Access Journals (Sweden)
Takuya Suzuki
2016-09-01
Full Text Available The uplift behavior of structures subjected to severe seismic motion has not been clarified. This paper presents experimental and analytical studies conducted for clarifying this problem of spread foundation structures on rock. First, centrifugal loading tests are conducted to determine the uplift behavior of these structures, and the uplift behavior of these structures is confirmed. Then, simulation analyses are performed using a three-dimensional FE model and the accuracy of these analyses is confirmed. A comparison between test and analyses results clarified the important analytical conditions required for maintaining analysis precision and the limit of analysis precision.
International Nuclear Information System (INIS)
Hasegawa, M.; Ichikawa, T.; Nakai, S.; Watanabe, T.
1987-01-01
A practical method to calculate the elasto-plastic seismic response of structures considering the dynamic soil-structure interaction is presented. The substructure technique in the time domain is utilized in the proposed method. A simple soil spring system with the coupling effects which are usually evaluated by the impedance matrix is introduced to consider the soil-structure interaction for embedded structures. As a numerical example, the response of a BWR-MARK II type reactor building embedded in the layered soil is calculated. The accuracy of the present method is verified by comparing its numerical results with exact solutions. The nonlinear behaivor and the soil-structure interaction effects on the response of the reactor building are also discussed in detail. It is concluded that the present method is effective for the aseismic design considering both the material nonlinearity of the nuclear reactor building and the dynamic soil-structure interaction. (orig.)
Reduction of seismic response in breeder plants
International Nuclear Information System (INIS)
Tajirian, F.F.; Somes, N.F.; Todeschini, R.A.
1984-01-01
Thin-walled vessels to be used in the Nuclear Steam Supply Systems (NSSS) of future LMFBR's will be more sensitive to seismic excitation than their equivalents used in conventional LWR plants. Optimization studies of building arrangement have indicated that embedment of future plants may be one feasible strategy for reducing seismic response. This paper presents the results of a three-dimensional soil-structure interaction analysis using the computer program SASSI. Two types of embedded buildings are considered: full embedment of the nuclear island, and embedment of the reactor cavity alone. A comparison, between the response of the embedded structure with that of a plant supported on the surface, indicates that the seismic response at the reactor vessel support ledge can be lowered by embedment of either the entire nuclear island or the reactor cavity alone. This reduction is larger when the plant is embedded in a softer site due to the increased effect of soil-structure interaction
Time Analysis of Building Dynamic Response Under Seismic Action. Part 2: Example of Calculation
Ufimtcev, E. M.
2017-11-01
The second part of the article illustrates the use of the time analysis method (TAM) by the example of the calculation of a 3-storey building, the design dynamic model (DDM) of which is adopted in the form of a flat vertical cantilever rod with 3 horizontal degrees of freedom associated with floor and coverage levels. The parameters of natural oscillations (frequencies and modes) and the results of the calculation of the elastic forced oscillations of the building’s DDM - oscillograms of the reaction parameters on the time interval t ∈ [0; 131,25] sec. The obtained results are analyzed on the basis of the computed values of the discrepancy of the DDS motion equation and the comparison of the results calculated on the basis of the numerical approach (FEM) and the normative method set out in SP 14.13330.2014 “Construction in Seismic Regions”. The data of the analysis testify to the accuracy of the construction of the computational model as well as the high accuracy of the results obtained. In conclusion, it is revealed that the use of the TAM will improve the strength of buildings and structures subject to seismic influences when designing them.
International Nuclear Information System (INIS)
Tagart, S.W.
1978-01-01
The seismic analysis of nuclear components is characterized today by extensive engineering computer calculations in order to satisfy both the component standard codes such as ASME III as well as federal regulations and guides. The current nuclear siesmic design procedure has envolved in a fragmented fashion and continues to change its elements as improved technology leads to changing standards and guides. The dominant trend is a monotonic increase in the overall conservation with time causing a similar trend in costs of nuclear power plants. Ironically the improvements in the state of art are feeding a process which is eroding the very incentives that attracted us to nuclear power in the first place. This paper examines the cause of this process and suggests that what is needed is a realistic goal which appropriately addresses the overall uncertainty of the seismic design process. (Auth.)
Response Analysis of an RC Cooling Tower Under Seismic and Windstorm Effects
Directory of Open Access Journals (Sweden)
D. Makovička
2006-01-01
Full Text Available The paper compares the RC structure of a cooling tower unit under seismic loads and under strong wind loads. The calculated values of the envelopes of the displacements and the internal forces due to seismic loading states are compared with the envelopes of the loading states due to the dead, operational and live loads, wind and temperature actions. The seismic effect takes into account the seismic area of ground motion 0.3 g and the ductility properties of a relatively rigid structure. The ductility is assessed as the reduction in seismic load. In this case the actions of wind pressure are higher than the seismicity effect under ductility correction. The seismic effects, taking into account the ductility properties of the structure, are lower than the actions of the wind pressure. The other static loads, especially temperature action due to the environment and surface insulation are very important for the design of the structure.
Seismic design and analysis methods
International Nuclear Information System (INIS)
Varpasuo, P.
1993-01-01
Seismic load is in many areas of the world the most important loading situation from the point of view of structural strength. Taking this into account it is understandable, that there has been a strong allocation of resources in the seismic analysis during the past ten years. In this study there are three areas of the center of gravity: (1) Random vibrations; (2) Soil-structure interaction and (3) The methods for determining structural response. The solution of random vibration problems is clarified with the aid of applications in this study and from the point of view of mathematical treatment and mathematical formulations it is deemed sufficient to give the relevant sources. In the soil-structure interaction analysis the focus has been the significance of frequency dependent impedance functions. As a result it was obtained, that the description of the soil with the aid of frequency dependent impedance functions decreases the structural response and it is thus always the preferred method when compared to more conservative analysis types. From the methods to determine the C structural response the following four were tested: (1) The time history method; (2) The complex frequency-response method; (3) Response spectrum method and (4) The equivalent static force method. The time history appeared to be the most accurate method and the complex frequency-response method did have the widest area of application. (orig.). (14 refs., 35 figs.)
International Nuclear Information System (INIS)
Ikushima, Takeshi
1995-11-01
The computer program ROCKING has been developed for seismic response analysis, which includes rocking and sliding behavior, of radioactive materials transport and/or storage casks. Main features of ROCKING are as follows; (1) Cask is treated as a rigid body. (2) Rocking and sliding behavior are considered. (3) Impact forces are represented by the spring dashpot model located at impact points. (4) Friction force is calculated at interface between a cask and a floor. (5) Forces of wire ropes against tip-over work only as tensile loads. In the paper, the calculation model, the calculation equations, validity calculations and user's manual are shown. (author)
Seismic response analysis and upgrading design of pump houses of Kozloduy NPP units 5 and 6
International Nuclear Information System (INIS)
Jordanov, M.; Marinov, M.; Krutzik, N.
2001-01-01
The main objective of the presented project was to perform a feasibility study for seismic/structural evaluation of the safety related structures at Kozloduy NPP Units 5 and 6 for the new site seismicity and determine if they satisfy current international safety standards. The evaluation of the Pump House 3 (PH3) building is addressed in this paper, which was carried out by applying appropriate modeling techniques combined with failure mode and seismic margin analyses. The scope of the work defined was to present the required enhancement of the seismic capacity of the Pump House structures.(author)
Quantitative Seismic Amplitude Analysis
Dey, A.K.
2011-01-01
The Seismic Value Chain quantifies the cyclic interaction between seismic acquisition, imaging and reservoir characterization. Modern seismic innovation to address the global imbalance in hydrocarbon supply and demand requires such cyclic interaction of both feed-forward and feed-back processes.
Seismic analysis of piping with nonlinear supports
International Nuclear Information System (INIS)
Barta, D.A.; Huang, S.N.; Severud, L.K.
1980-01-01
The modeling and results of nonlinear time-history seismic analyses for three sizes of pipelines restrained by mechanical snubbes are presented. Numerous parametric analyses were conducted to obtain sensitivity information which identifies relative importance of the model and analysis ingredients. Special considerations for modeling the pipe clamps and the mechanical snubbers based on experimental characterization data are discussed. Comparisions are also given of seismic responses, loads and pipe stresses predicted by standard response spectra methods and the nonlinear time-history methods
Development of seismic hazard analysis in Japan
International Nuclear Information System (INIS)
Itoh, T.; Ishii, K.; Ishikawa, Y.; Okumura, T.
1987-01-01
In recent years, seismic risk assessment of the nuclear power plant have been conducted increasingly in various countries, particularly in the United States to evaluate probabilistically the safety of existing plants under earthquake loading. The first step of the seismic risk assessment is the seismic hazard analysis, in which the relationship between the maximum earthquake ground motions at the plant site and their annual probability of exceedance, i.e. the seismic hazard curve, is estimated. In this paper, seismic hazard curves are evaluated and examined based on historical earthquake records model, in which seismic sources are modeled with area-sources, for several different sites in Japan. A new evaluation method is also proposed to compute the response spectra of the earthquake ground motions in connection with estimating the probabilistic structural response. Finally the numerical result of probabilistic risk assessment for a base-isolated three story RC structure, in which the frequency of seismic induced structural failure is evaluated combining the seismic hazard analysis, is described briefly
Analysis of EAST tokamak cryostat anti-seismic performance
International Nuclear Information System (INIS)
Chen Wei; Kong Xiaoling; Liu Sumei; Ni Xiaojun; Wang Zhongwei
2014-01-01
A 3-D finite element model for EAST tokamak cryostat is established by using ANSYS. On the basis of the modal analysis, the seismic response of the EAST tokamak cryostat structure is calculated according to an input of the design seismic response spectrum referring to code for seismic design of nuclear power plants. Calculation results show that EAST cryostat displacement and stress response is small under the action of earthquake. According to the standards, EAST tokamak cryostat structure under the action of design seismic can meet the requirements of anti-seismic design intensity, and ensure the anti-seismic safety of equipment. (authors)
Analysis for seismic response of dry storage facility for spent fuel
International Nuclear Information System (INIS)
Ko, Y.-Y.; Hsu, S.-Y.; Chen, C.-H.
2009-01-01
Most of the dry storage systems for spent fuel are freestanding, which leads to stability concerns in an earthquake. In this study, as a safety check, the ABAQUS/Explicit code is adopted to analyse the seismic response of the dry storage facility planned to be installed at Nuclear Power Plant no. 1 (NPP1) in Taiwan. A 3D coupled finite element (FE) model was established, which consisted of a freestanding cask, a concrete pad, and underneath soils interacting with frictional contact interfaces. The scenario earthquake used in the model included an artificial earthquake compatible to the design spectrum of NPP1, and a strong ground motion modified from the time history recorded during the Chi-Chi earthquake. The results show that the freestanding cask will slide, but not tip over, during strong earthquakes. The scale of the sliding is very small and a collision between casks will not occur. In addition, the differential settlement of the foundation pad that takes place due to the weight of the casks increases the sliding potential of the casks during earthquakes
International Nuclear Information System (INIS)
Mizuno, N.; Iida, T.; Tsushima, Y.; Araki, T.; Nojima, O.
1977-01-01
In this paper, the seismic response analysis is described in detail for estimating the soil-structure interaction effects with the torsional behavior. The analytical method is firstly shown for estimating the stiffness of reactor building by the bending-shear and torsion theory of the thin wall sections in regard to the behavior of structure. The three-dimensional behavior of structure can be obtained more briefly and simply by the proposed method. Secondly, the dynamical soil-foundation coefficient for estimating the dissipation of vibrational energy on the ground is derived by H. Tajimi's theory which is based on a solution of the propagation of seismic waves caused by point excitation on the surface of the elastic half-space medium. The above results give the vibrational impedances of the soil-foundation corresponding to the static soil coefficient, which is defined to the excitation force in the frequency domain. In order to analyze to the equivalues of reactor building, the authors thirdly attempt to approximate the dynamic soil-foundation coefficient as the frequency transfer function of displacement. The complex damping is used for more suitably estimating the elastic structural damping effects of structure. The regression analysis of many degrees of freedom is fourthly attempted for estimating the natural periods annd equivalent viscous damping ratios directly from the experimental results by the forced vibrational test performed in 1974. The analytical results are finally shown for simulating and comparing with the above-mentioned experimental results
Seismic analysis program group: SSAP
International Nuclear Information System (INIS)
Uchida, Masaaki
2002-05-01
A group of programs SSAP has been developed, each member of which performs seismic calculation using simple single-mass system model or multi-mass system model. For response of structures to a transverse s-wave, a single-mass model program calculating response spectrum and a multi-mass model program are available. They perform calculation using the output of another program, which produces simulated earthquakes having the so-called Ohsaki-spectrum characteristic. Another program has been added, which calculates the response of one-dimensional multi-mass systems to vertical p-wave input. It places particular emphasis on the analysis of the phenomena observed at some shallow earthquakes in which stones jump off the ground. Through a series of test calculations using these programs, some interesting information has been derived concerning the validity of superimposing single-mass model calculation, and also the condition for stones to jump. (author)
Site response assessment using borehole seismic records
Energy Technology Data Exchange (ETDEWEB)
Park, Donghee; Chang, Chunjoong; Choi, Weonhack [KHNP Central Research Institute, Daejeon (Korea, Republic of)
2014-05-15
In regions with high seismic activity, such as Japan, the Western United States and Taiwan, borehole seismometers installed deep underground are used to monitor seismic activity during the course of seismic wave propagation at various depths and to study the stress changes due to earthquakes and analyze the connection to fault movements. The Korea Meteorological Administration (KMA) and the Korea Institute of Geology and Mining (KIGAM) have installed and are operating borehole seismometers at a depth of 70∼100 meters for the precise determination of epicenters. Also, Korea Hydro and Nuclear Power Co., Ltd. (KHNP) has installed and is operating 2 borehole seismic stations near Weolseong area to observe at a depth of 140 meters seismic activities connected to fault activity. KHNP plans to operate in the second half of 2014 a borehole seismic station for depths less than 300 and 600 meters in order to study the seismic response characteristics in deep strata. As a basic study for analyzing ground motion response characteristics at depths of about 300 to 600 meters in connection with the deep geological disposal of spent nuclear fuel, the present study examined the background noise response characteristics of the borehole seismic station operated by KHNP. In order to analyze the depth-dependent impact of seismic waves at deeper depths than in Korea, seismic data collected by Japan's KIK-net seismic stations were used and the seismic wave characteristics analyzed by size and depth. In order to analyze the borehole seismic observation data from the seismic station operated by KHNP, this study analyzed the background noise characteristics by using a probability density function.
Site response assessment using borehole seismic records
International Nuclear Information System (INIS)
Park, Donghee; Chang, Chunjoong; Choi, Weonhack
2014-01-01
In regions with high seismic activity, such as Japan, the Western United States and Taiwan, borehole seismometers installed deep underground are used to monitor seismic activity during the course of seismic wave propagation at various depths and to study the stress changes due to earthquakes and analyze the connection to fault movements. The Korea Meteorological Administration (KMA) and the Korea Institute of Geology and Mining (KIGAM) have installed and are operating borehole seismometers at a depth of 70∼100 meters for the precise determination of epicenters. Also, Korea Hydro and Nuclear Power Co., Ltd. (KHNP) has installed and is operating 2 borehole seismic stations near Weolseong area to observe at a depth of 140 meters seismic activities connected to fault activity. KHNP plans to operate in the second half of 2014 a borehole seismic station for depths less than 300 and 600 meters in order to study the seismic response characteristics in deep strata. As a basic study for analyzing ground motion response characteristics at depths of about 300 to 600 meters in connection with the deep geological disposal of spent nuclear fuel, the present study examined the background noise response characteristics of the borehole seismic station operated by KHNP. In order to analyze the depth-dependent impact of seismic waves at deeper depths than in Korea, seismic data collected by Japan's KIK-net seismic stations were used and the seismic wave characteristics analyzed by size and depth. In order to analyze the borehole seismic observation data from the seismic station operated by KHNP, this study analyzed the background noise characteristics by using a probability density function
Seismic response of buried pipelines: a state-of-the-art review
International Nuclear Information System (INIS)
Datta, T.K.
1999-01-01
A state-of-the-art review of the seismic response of buried pipelines is presented. The review includes modeling of soil-pipe system and seismic excitation, methods of response analysis of buried pipelines, seismic behavior of buried pipelines under different parametric variations, seismic stresses at the bends and intersections of network of pipelines. pipe damage in earthquakes and seismic risk analysis of buried pipelines. Based on the review, the future scope of work on the subject is outlined. (orig.)
PSMG switchgear seismic analysis
International Nuclear Information System (INIS)
Kuehster, C.J.
1977-01-01
LOFT primary coolant system motor generator (PSMG) switchgear boxes were analyzed for sliding and overturning during a seismic event. Boxes are located in TAN-650, Room B-239, with the PSMG generators. Both boxes are sufficiently anchored to the floor
SEISMIC ANALYSIS FOR PRECLOSURE SAFETY
Energy Technology Data Exchange (ETDEWEB)
E.N. Lindner
2004-12-03
The purpose of this seismic preclosure safety analysis is to identify the potential seismically-initiated event sequences associated with preclosure operations of the repository at Yucca Mountain and assign appropriate design bases to provide assurance of achieving the performance objectives specified in the Code of Federal Regulations (CFR) 10 CFR Part 63 for radiological consequences. This seismic preclosure safety analysis is performed in support of the License Application for the Yucca Mountain Project. In more detail, this analysis identifies the systems, structures, and components (SSCs) that are subject to seismic design bases. This analysis assigns one of two design basis ground motion (DBGM) levels, DBGM-1 or DBGM-2, to SSCs important to safety (ITS) that are credited in the prevention or mitigation of seismically-initiated event sequences. An application of seismic margins approach is also demonstrated for SSCs assigned to DBGM-2 by showing a high confidence of a low probability of failure at a higher ground acceleration value, termed a beyond-design basis ground motion (BDBGM) level. The objective of this analysis is to meet the performance requirements of 10 CFR 63.111(a) and 10 CFR 63.111(b) for offsite and worker doses. The results of this calculation are used as inputs to the following: (1) A classification analysis of SSCs ITS by identifying potential seismically-initiated failures (loss of safety function) that could lead to undesired consequences; (2) An assignment of either DBGM-1 or DBGM-2 to each SSC ITS credited in the prevention or mitigation of a seismically-initiated event sequence; and (3) A nuclear safety design basis report that will state the seismic design requirements that are credited in this analysis. The present analysis reflects the design information available as of October 2004 and is considered preliminary. The evolving design of the repository will be re-evaluated periodically to ensure that seismic hazards are properly
SEISMIC ANALYSIS FOR PRECLOSURE SAFETY
International Nuclear Information System (INIS)
E.N. Lindner
2004-01-01
The purpose of this seismic preclosure safety analysis is to identify the potential seismically-initiated event sequences associated with preclosure operations of the repository at Yucca Mountain and assign appropriate design bases to provide assurance of achieving the performance objectives specified in the Code of Federal Regulations (CFR) 10 CFR Part 63 for radiological consequences. This seismic preclosure safety analysis is performed in support of the License Application for the Yucca Mountain Project. In more detail, this analysis identifies the systems, structures, and components (SSCs) that are subject to seismic design bases. This analysis assigns one of two design basis ground motion (DBGM) levels, DBGM-1 or DBGM-2, to SSCs important to safety (ITS) that are credited in the prevention or mitigation of seismically-initiated event sequences. An application of seismic margins approach is also demonstrated for SSCs assigned to DBGM-2 by showing a high confidence of a low probability of failure at a higher ground acceleration value, termed a beyond-design basis ground motion (BDBGM) level. The objective of this analysis is to meet the performance requirements of 10 CFR 63.111(a) and 10 CFR 63.111(b) for offsite and worker doses. The results of this calculation are used as inputs to the following: (1) A classification analysis of SSCs ITS by identifying potential seismically-initiated failures (loss of safety function) that could lead to undesired consequences; (2) An assignment of either DBGM-1 or DBGM-2 to each SSC ITS credited in the prevention or mitigation of a seismically-initiated event sequence; and (3) A nuclear safety design basis report that will state the seismic design requirements that are credited in this analysis. The present analysis reflects the design information available as of October 2004 and is considered preliminary. The evolving design of the repository will be re-evaluated periodically to ensure that seismic hazards are properly
SONATINA-1: a computer program for seismic response analysis of column in HTGR core
International Nuclear Information System (INIS)
Ikushima, Takeshi
1980-11-01
An computer program SONATINA-1 for predicting the behavior of a prismatic high-temperature gas-cooled reactor (HTGR) core under seismic excitation has been developed. In this analytical method, blocks are treated as rigid bodies and are constrained by dowel pins which restrict relative horizontal movement but allow vertical and rocking motions. Coulomb friction between blocks and between dowel holes and pins is also considered. A spring dashpot model is used for the collision process between adjacent blocks and between blocks and boundary walls. Analytical results are compared with experimental results and are found to be in good agreement. The computer program can be used to predict the behavior of the HTGR core under seismic excitation. (author)
International Nuclear Information System (INIS)
Suzuki, K.; Sato, H.
1975-01-01
The power and the cross power spectrum analysis by which the vibration characteristic of structures, such as natural frequency, mode of vibration and damping ratio, can be identified would be effective for the confirmation of the characteristics after the construction is completed by using the response for small earthquakes or the micro-tremor under the operating condition. This method of analysis previously utilized only from the view point of systems with single input so far, is extensively applied for the analysis of a medium scale model of a piping system subjected to two seismic inputs. The piping system attached to a three storied concrete structure model which is constructed on a shaking table was excited due to earthquake motions. The inputs to the piping system were recorded at the second floor and the ceiling of the third floor where the system was attached to. The output, the response of the piping system, was instrumented at a middle point on the system. As a result, the multi-dimensional power spectrum analysis is effective for a more reliable identification of the vibration characteristics of the multi-input structure system
Seismic responses of unanchored electrode storage fixtures
International Nuclear Information System (INIS)
Ting-shu Wu; Blomquist, C.A.; Haupt, H.J.; Herceg, J.E.
1993-01-01
Two anchored electrode storage fixtures will be installed in the process cell of the Integral Fast Reactor's Fuel Cycle Facility at ANL-W in Idaho. In addition to the concerns for structural integrity, the potential for uplifting and tipping of the fixtures during the design basis earthquake must also be examined. In the analysis, a response-spectrum method was employed to investigate tipping, while a static approach was used for the structural-integrity evaluations. The results show that the combined stresses from seismic and other loads are within the allowables permitted by the design codes. The overall vertical seismic reaction forces at the leveling pads are compressive, implying that the fixtures will remain in contact with the floor. No uplifting or tipping of the fixture will occur during the design basis earthquake
International Nuclear Information System (INIS)
Avila, Jorge A.; Martinez, Eduardo
2008-01-01
Based on a ductile frames 25 level building, a non-linear analysis with increased monotonically lateral loads (Push-Over) was made in order to determine its collapse and its principal responses were compared against the time-history seismic responses determined with the SCT-EW-85 record. The seismic-resistance design and faced to gravitational loads was made according to the Complementary Technical Norms of Concrete Structures Design (NTC-Concrete) and the NTC-Seismic of the Mexico City Code (RDF-04), satisfying the limit service states (relative lateral displacement between story height maximum relations, story drifts ≤0.012) and failure (seismic behavior factor, Q = 3). The compressible (soft) seismic zone III b and the office use type (group B) were considered. The non-lineal responses were determined with nominal and over-resistance effects. The comparison were made with base shear force-roof lateral displacement relations, global distribution of plastic hinges, failure mechanics tendency, lateral displacements and story drift and its distribution along the height of the building, local and global ductility demands, etc. For the non-linear static analysis with increased monotonically lateral loads, was important to select the type of lateral forces distribution
International Nuclear Information System (INIS)
Juhasova, E.
1999-01-01
The work described in this report was devoted to investigation of expected seismic response of the structures of WWER-440/213 type NPPs, namely Mochovce and Bohunice. Special attention was devoted to the properties of subsoil materials and the transfer of seismic waves from the bedrock to the foundation structures. Theoretical background was elaborated and discussed for wave propagation of surface waves. Alternative procedure was derived for non-linear media accounting for complex modulus theory. Material characteristics of subsoils were investigated for both NPPs. The obtained results were used as a basis for forecasting and calculation of expected seismic response when the time history records from Paks explosion were used an input. It was pointed out that the used procedure, together with previous calculation of subsoil transfer characteristics completed well the comparison with experimental results
Seismic response of uplifting concrete gravity dams
International Nuclear Information System (INIS)
Leger, P.; Sauve, G.; Bhattacharjee, S.
1992-01-01
The foundation interaction effects on the seismic response of dam-foundation systems have generally been studied using the linear elastic finite element models. In reality, the foundation can not develop effective tensile stresses to a significant degree along the interface. A two-dimensional finite element model, in which nonlinear gap elements are used at the dam-foundation interface to determine the uplift response of concrete gravity dams subjected to seismic loads, is presented. Time domain analyses were performed for a wide range of modelling assumptions such as dam height, interface uplift pressure, interface mesh density, and earthquake input motions, that were systematically varied to find their influence on the seismic response. The nonlinear interface behavior generally reduces the seismic response of dam-foundation systems acting as a seismic isolation mechanism, and may increase the safety against sliding by reducing the base shear transmitted to the foundation. 4 refs., 5 figs., 6 tabs
Seismic shear wall ISP NUPEC's seismic ultimate dynamic response test. Comparison report
International Nuclear Information System (INIS)
1996-01-01
In the seismic design of a nuclear power plant, evaluation of the ultimate strength of the nuclear reactor building is an important subject for assessment of seismic reliability of the plant. In order to carry out the evaluation, the response characteristics of reinforced concrete seismic shear walls up to their ultimate state have to be understood. For this purpose, there is a need to develop reliable non-linear response analysis methods which enables the reliable ultimate strength evaluation of nuclear reactor buildings. Along with this need, many computer codes have been developed. These computer codes are compared. (K.A.)
Butler, Thomas G.
1993-09-01
There is a constant need to be able to solve for enforced motion of structures. Spacecraft need to be qualified for acceleration inputs. Truck cargoes need to be safeguarded from road mishaps. Office buildings need to withstand earthquake shocks. Marine machinery needs to be able to withstand hull shocks. All of these kinds of enforced motions are being grouped together under the heading of seismic inputs. Attempts have been made to cope with this problem over the years and they usually have ended up with some limiting or compromise conditions. The crudest approach was to limit the problem to acceleration occurring only at a base of a structure, constrained to be rigid. The analyst would assign arbitrarily outsized masses to base points. He would then calculate the magnitude of force to apply to the base mass (or masses) in order to produce the specified acceleration. He would of necessity have to sacrifice the determination of stresses in the vicinity of the base, because of the artificial nature of the input forces. The author followed the lead of John M. Biggs by using relative coordinates for a rigid base in a 1975 paper, and again in a 1981 paper . This method of relative coordinates was extended and made operational as DMAP ALTER packets to rigid formats 9, 10, 11, and 12 under contract N60921-82-C-0128. This method was presented at the twelfth NASTRAN Colloquium. Another analyst in the field developed a method that computed the forces from enforced motion then applied them as a forcing to the remaining unknowns after the knowns were partitioned off. The method was translated into DMAP ALTER's but was never made operational. All of this activity jelled into the current effort. Much thought was invested in working out ways to unshakle the analysis of enforced motions from the limitations that persisted.
Consideration of vertical seismic response spectrum in nuclear safety review
International Nuclear Information System (INIS)
Sun Zaozhan; Huang Bingchen
2011-01-01
The basic requirements for civil nuclear installation are introduced in the article. Starting from the basic concept of seismic response spectrum, the authors analyze the site seismic response spectrum and the design seismic response spectrum that desire much consideration. By distinguishing the absolute seismic response spectrum and relative seismic response spectrum, the authors analyze the difference and relationship between the vertical seismic response spectrum and horizontal seismic response spectrum. The authors also bring forward some suggestions for determining the site vertical seismic response spectrum by considering the fact in our country. (authors)
Seismic analysis of nuclear power plants
International Nuclear Information System (INIS)
Halbritter, A.L.
1984-01-01
Nuclear Power Plants require exceptional safety guarantees which are reflected in a rigorous control of the employed materials, advanced construction technology, sophisticated methods of analysis and consideration of non conventional load cases such as the earthquake loading. In this paper, the current procedures used in the seismic analysis of Nuclear Power Plants are presented. The seismic analysis of the structures has two objectives: the determination of forces in the structure in order to design it against earthquakes and the generation of floor response spectra to be used in the design of mechanical and electrical components and piping systems. (Author) [pt
Nonlinear seismic analysis of a large sodium pump
International Nuclear Information System (INIS)
Huang, S.N.
1985-01-01
The bearings and seismic bumpers used in a large sodium pump of a typical breeder reactor plant may need to be characterized by nonlinear springs and gaps. Then, nonlinear seismic analysis utilizing the time-history method is an effective way to predict the pump behaviors during seismic events - especially at those bearing and seismic bumper areas. In this study, synthesized time histories were developed based on specified seismic response spectra. A nonlinear seismic analysis was then conducted and results were compared with those obtained by linear seismic analysis using the response spectrum method. In contrast to some previous nonlinear analysis trends, the bearing impact forces predicted by nonlinear analysis were higher than those obtained by the response spectrum method. This might be due to the larger gaps and stiffer bearing supports used in this specific pump. However, at locations distant from the impact source, the nonlinear seismic analysis has predicted slightly less responses than those obtained by linear seismic analysis. The seismically induced bearing impact forces were used to study the friction induced thermal stresses on the hydrostatic bearing and to predict the coastdown time of the pump. Results and discussions are presented
Nonlinear seismic analysis of a large sodium pump
International Nuclear Information System (INIS)
Huang, S.N.
1985-01-01
The bearings and seismic bumpers used in a large sodium pump of a typical breeder reactor plant may need to be characterized by nonlinear springs and gaps. Then, nonlinear seismic analysis utilizing the time-history method is an effective way to predict the pump behaviors during seismic events, especially at those bearing and seismic bumper areas. In this study, synthesized time histories were developed based on specified seismic response spectra. A nonlinear seismic analysis was then conducted and results were compared with those obtained by linear seismic analysis using the response spectrum method. In contrast to some previous nonlinear analysis trends, the bearing impact forces predicted by nonlinear analysis were higher than those obtained by the response spectrum method. This might be due to the larger gaps and stiffer bearing supports used in this specific pump. However, at locations distant from the impact source, the nonlinear seismic analysis has predicted slightly less responses than those obtained by linear seismic analysis. The seismically induced bearing impact forces were used to study the friction induced thermal stresses on the hydrostatic bearing and to predict the coastdown time of the pump. Results and discussions are presented
Influence of plastic deformation on seismic response of piping
International Nuclear Information System (INIS)
Yao Yanping; Chen Yong; Lu Mingwan
2000-01-01
On the basis of a brief summary of linear elastic seismic analysis methods, the importance for consideration of plastic deformation during the dynamic response analysis of piping system is indicated. The present methods of considering plasticity and the disadvantages of these methods are discussed. And the authors point out that in order to reduce the conservatism of present codes and to put forward appropriate and realistic piping seismic design methods, the key is to understand the plastic dynamic failure mode for piping under seismic excitation and to calculate the inelastic energy dissipation. The analysis and evaluation are applicable to nuclear piping systems
Conceptual design by analysis of KALIMER seismic isolation
International Nuclear Information System (INIS)
You, Bong; Koo, Kyung Hoi; Lee, Jae Han
1996-06-01
The objectives of this report are to preliminarily evaluate the seismic isolation performance of KALIMER (Korea Advance LIquid MEtal Reactor) by seismic analyses, investigate the design feasibility, and find the critical points of KALIMER reactor structures. The work scopes performed in this study are 1) the establishment of seismic design basis, 2) the development of seismic analysis model of KALIMER, 3) the modal analysis, 4) seismic time history analysis, 5) the evaluations of seismic isolation performance and seismic design margins, and 6) the evaluation of seismic capability of KALIMER. The horizontal fundamental frequency of KALIMER reactor structure is 8 Hz, which is far remote from the seismic isolation frequency, 0.7 Hz. The vertical first and second natural frequencies are about 2 Hz and 8 Hz respectively. These vertical natural frequencies are in a dominant ground motion frequency bands, therefore these modes will result in large vertical response amplifications. From the results of seismic time history analyses, the horizontal isolation performance is great but the large vertical amplifications are occurred in reactor structures. The RV Liner has the smallest seismic design margin as 0.18. From the results of seismic design margins evaluation, the critical design change are needed in the support barrel, separation plate, and baffle plate points. The seismic capability of KALIMER is about 0.35g. This value can be increased by the design changes of the separation plate and etc.. 11 tabs., 29 figs., 7 refs. (Author) .new
Subsystem response review. Seismic safety margins research program
International Nuclear Information System (INIS)
Kennedy, R.P.; Campbell, R.D.; Wesley, D.A.; Kamil, H.; Gantayat, A.; Vasudevan, R.
1981-07-01
A study was conducted to document the state of the art in seismic qualification of nuclear power plant components and subsystems by analysis and testing and to identify the sources and magnitude of the uncertainties associated with analysis and testing methods. The uncertainties are defined in probabilistic terms for use in probabilistic seismic risk studies. Recommendations are made for the most appropriate subsystem response analysis methods to minimize response uncertainties. Additional studies, to further quantify testing uncertainties, are identified. Although the general effect of non-linearities on subsystem response is discussed, recommendations and conclusions are based principally on linear elastic analysis and testing models. (author)
International Nuclear Information System (INIS)
Byun, Y.J.; Kim, J.G.; Sung, K.K.; Lee, D.H.
2015-01-01
This paper deals with 3 topics concerning the APR1400 reactor vessel internals (RVI) seismic analysis: nonlinear problems, approaches to account for uncertainties of seismic model, and dynamic responses to various seismic excitations. First, the noticeable nonlinear characteristics of the RVI seismic model are discussed, and the modeling methods for properly simulating the nonlinear behaviors of RVI under seismic loads are presented. By applying these methods to the seismic model, the seismic analysis can correctly predict the dynamic response of RVI. Next, two approaches to account for the uncertainties of seismic model are evaluated: the time history broadening method, and the sensitivity analysis based on NUREG-0800, Section 4.2, Appendix A. From the evaluation results, it is confirmed that the time history broadening method employed in the seismic analysis of APR1400 RVI sufficiently accounts for the uncertainty of seismic model. Finally, the response characteristics of APR1400 RVI to various seismic excitations are investigated. The seismic excitations corresponding to various soil profiles, including the effects of cracked and un-cracked concrete stiffness on the reactor containment building structure, are used as forcing functions. From this study, the effects of various site conditions on the dynamic response of APR1400 RVI are identified. As a result, the enveloped seismic responses obtained from this study will contribute to the development of RVI seismic design that covers a wide range of potential site conditions. (authors)
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, R.; Ni, S.; Chen, R.; Han, X.M. [CANDU Energy Inc, Mississauga, Ontario (Canada); Mullin, D. [New Brunswick Power, Point Lepreau, New Brunswick (Canada)
2016-09-15
Seismic fragility analyses are conducted as part of seismic probabilistic safety assessment (SPSA) for nuclear facilities. Probabilistic seismic hazard assessment (PSHA) has been undertaken for a nuclear power plant in eastern Canada. Uniform Hazard Spectra (UHS), obtained from the PSHA, is characterized by high frequency content which differs from the original plant design basis earthquake spectral shape. Seismic fragility calculations for the service building of a CANDU 6 nuclear power plant suggests that the high frequency effects of the UHS can be mitigated through site response analysis with site specific geological conditions and state-of-the-art soil-structure interaction analysis. In this paper, it is shown that by performing a detailed seismic analysis using the latest technology, the conservatism embedded in the original seismic design can be quantified and the seismic capacity of the building in terms of High Confidence of Low Probability of Failure (HCLPF) can be improved. (author)
Response of cylindrical steel shell under seismic loading
International Nuclear Information System (INIS)
Tariq, M.; Amin, K.M.
2003-01-01
The seismic response of a cylindrical shell is simulated using the finite element method, and by spectral analysis. For this purpose the fundamental frequency of the cylinder is first calculated and compared with a published result. The mode shapes are also calculated which are later used for spectral analysis. The boundary nodes of the shell are displaced periodically according to a predetermined function of time by employing the acceleration time history of the El Centro earthquake to simulate the seismic loading. However, to conduct spectral analysis, the displacements are first transformed from the time domain to frequency domain using the Fast Fourier transformation. This spectral data is then used to obtain the actual displacement in the first mode under the given seismic loading. The techniques employed here can be used for cylindrical shell structures like rotor of a gas centrifuge, besides other structures that are subjected to seismic loading, besides in other time dependent loading conditions, for example rocket motor vibrations. (author)
Seismic analysis of nuclear piping system
International Nuclear Information System (INIS)
Shrivastava, S.K.; Pillai, K.R.V.; Nandakumar, S.
1975-01-01
To illustrate seismic analysis of nuclear power plant piping, a simple piping system running between two floors of the reactor building is assumed. Reactor building floor response is derived from time-history method. El Centre earthquake (1940) accelerogram is used for time-history analysis. The piping system is analysed as multimass lumped system. Behaviour of the pipe during the said earthquake is discussed. (author)
Seismic analysis of axisymmetric shells
International Nuclear Information System (INIS)
Jospin, R.J.; Toledo, E.M.; Feijoo, R.A.
1984-01-01
Axisymmetric shells subjected to multiple support excitation are studied. The shells are spatialy discretized by the finite element method and in order to obtain estimates for the maximum values of displacements and stresses the response spectrum tecnique is used. Finally, some numerical results are presented and discussed in the case of a shell of revolution with vertical symmetry axis, subjected to seismic ground motions in the horizontal, vertical and rocking directions. (Author) [pt
Nonlinear seismic analysis of continuous RC bridge
Directory of Open Access Journals (Sweden)
Čokić Miloš M.
2017-01-01
Full Text Available Nonlinear static analysis, known as a pushover method (NSPA is oftenly used to study the behaviour of a bridge structure under the seismic action. It is shown that the Equivalent Linearization Method - ELM, recommended in FEMA 440, is appropriate for the response analysis of the bridge columns, with different geometric characteristics, quantity and distribution of steel reinforcement. The subject of analysis is a bridge structure with a carriageway plate - a continuous beam with three spans, with the 24 + 40 + 24 m range. Main girder is made of prestressed concrete and it has a box cross section of a constant height. It is important to study the behaviour, not only in the transverse, but also in the longitudinal direction of the bridge axis, when analysing the bridge columns exposed to horizontal seismic actions. The columns were designed according to EN1992, parts 1 and 2. Seismic action analysis is conducted according to EN 1998: 2004 standard. Response spectrum type 1, for the ground type B, was applied and the analysis also includes 20% of traffic load. The analysis includes the values of columns displacement and ductility. To describe the behaviour of elements under the earthquake action in both - longitudinal and transverse direction, pushover curves were formed.
International Nuclear Information System (INIS)
DeGrassi, G.
1992-10-01
This report presents the results of a literature review on spent fuel rack seismic analysis methods and modeling procedures. The analysis of the current generation of free standing high density spent fuel racks requires careful consideration of complex phenomena such as rigid body sliding and tilting motions; impacts between adjacent racks, between fuel assemblies and racks, and between racks and pool walls and floor; fluid coupling and frictional effects. The complexity of the potential seismic response of these systems raises questions regarding the levels of uncertainty and ranges of validity of the analytical results. BNL has undertaken a program to investigate and assess the strengths and weaknesses of current fuel rack seismic analysis methods. The first phase of this program involved a review of technical literature to identify the extent of experimental and analytical verification of the analysis methods and assumptions. Numerous papers describing analysis methods for free standing fuel racks were reviewed. However, the extent of experimental verification of these methods was found to be limited. Based on the information obtained from the literature review, the report provides an assessment of the significance of the issues of concern and makes recommendations for additional studies
International Nuclear Information System (INIS)
Tai, Koichi; Sasajima, Keisuke; Fukushima, Shunsuke; Takamura, Noriyuki; Onishi, Shigenobu
2014-01-01
This paper provides seismic design analysis methods suitable for crossover piping system, which connects between seismic isolated building and non-isolated building in the seismic isolated nuclear power plant. Through the numerical study focused on the main steam crossover piping system, seismic response spectrum analysis applying ISM (Independent Support Motion) method with SRSS combination or CCFS (Cross-oscillator, Cross-Floor response Spectrum) method has found to be quite effective for the seismic design of multiply supported crossover piping system. (author)
International Nuclear Information System (INIS)
Jehlicka, P.
1980-01-01
The determination of the dynamic response of nuclear power plants is a necessary part of safe design against earthquake, or against other additional vibrational loading. The determination of these dynamic loads caused by external excitation is a requirement in calculating the related material loading on the structures. The purpose of this lecture is to present a general survey of analytical methods to determine the response of structural and mechanical equipment to earthquake. The main problems which complicate structural-dynamic calculations will be discussed. The necessity to control input parameters and the possibility to calculate with simplified methods will be pointed out. (orig./RW)
Seismic response of LMFBR tanks with imperfections
International Nuclear Information System (INIS)
Gvildys, J.; Ma, D.C.; Chang, Y.W.
1985-01-01
This paper deals with seismic responses of imperfect circular tanks. Physical imperfection due to manufacturing tolerances and numerical imperfection due to finite element spatial discretization are described. Numerical imperfections produced by 4-node and 9-node Lagrangian shell elements are examined. A convergence study is performed in which the number of the shell elements required to capture the dominant ''out-of-roundness'' modes under seismic excitations is determined. The response of a shell with a cos4theta imperfection due to manufacturing tolerances is compared with that of a perfect circular shell to demonstrate the effects of imperfection on the axial stresses of the shell under seismic conditions. 3 refs., 4 figs., 2 tabs
Seismic analysis of the in-pile test section
Energy Technology Data Exchange (ETDEWEB)
Lee, J. M.; Park, K. N.; Chi, D. Y.; Park, S. K.; Sim, B. S.; Ahn, S. H.; Lee, C. Y.; Kim, Y. J. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)
2004-07-01
This study gives the results of the seismic analysis of the IPS (In Pile Section) with lower bracket support. The results cover the natural frequency and seismic response of the IPS for the SSE and OBE events. An FE (Finite Element) model which includes the two vessels of the IPS and its support structure were analyzed by ABAQUS.
ANALYSIS FOR EFFECT OF FPS-TYPED TMD CONTROLLING SEISMIC RESPONSES%FPS型TMD控震效应分析
Institute of Scientific and Technical Information of China (English)
李大望; 关罡; 霍达
2001-01-01
Based on the differential vibration equations of the multi-layer shear-type st ructure controlled by FPS-TMD,the seismic response laws of the structure are ca lculated and analyzed;the results display that the earthquake responses of the b uilding structures can be improved with a reasonable designed FPS-TMD.%基于FPS(Friction Pendulum System)型TMD(Turned Mass Damper)控制的多层剪切型结构振动微分方程，通过时程计算分析了FPS型TMD控震响应规律。结果表明，合理设计的FPS型TMD 控振系统可以改善结构的振动响应。
Seismic analysis of a containment vessel
International Nuclear Information System (INIS)
Toledo, E.M.; Jospin, R.J.; Loula, A.F.D.
1987-01-01
A seismic analysis of a nuclear power plant containment vessel is presented. Usual loads in this kind of analysis like SSE, DBE and SSB loadings are considered. With the response spectra, previously obtained, for the above mentioned loadings one uses the response spectrum techniques in order to obtain estimatives for the maximum values of the stresses. Some considerations about the problem and the approcah used herein, are initially described. Next, the analysed structure geometry and some results, compared with those obtained by using computer code ANSYS are shown. (Author) [pt
Structural Analysis and Seismic Design for Cold Neutron Laboratory Building
International Nuclear Information System (INIS)
Wu, Sangik; Kim, Y. K.; Kim, H. R.
2007-05-01
This report describes all the major results of the dynamic structural analysis and seismic design for the Cold Neutron Laboratory Building which is classified in seismic class II. The results are summarized of the ground response spectrum as seismic input loads, mechanical properties of subsoil, the buoyancy stability due to ground water, the maximum displacement of the main frame under the seismic load and the member design. This report will be used as a basic design report to maintenance its structural integrity in future
Seismic analysis for conceptual design of HCCR TBM-set
Energy Technology Data Exchange (ETDEWEB)
Lee, Dong Won, E-mail: dwlee@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Seong Dae; Jin, Hyung Gon; Lee, Eo Hwak; Kim, Suk-Kwon; Yoon, Jae Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Shin, Kyu In [Gentec Co., Daejeon, Republic of Korea (Korea, Republic of); Cho, Seungyon [National Fusion Research Institute, Daejeon (Korea, Republic of)
2016-11-01
Highlights: • The seismic analysis of KO HCCR TBM-set are performed. • The seismic envents like SL-1, SL-2, and SMHV are selected and evaluated with FEM code (ANSYS). • The results of the stresses and deformations are confirmed to meet the design criteria. - Abstract: Using the conceptual design of the Korean helium cooled ceramic reflector (HCCR) test blanket module (TBM) including the TBM-shield for testing in ITER, a seismic analysis is performed. According to the ITER TBM port plug (TBM PP) system load specifications, seismic events are selected as SL-1 (seismic level-1), SL-2 (seismic level-2), and SMHV (seismes maximaux historiquement vraisemblables, Maximum Histroically Probable Earthquakes). In a modal analysis a total of 50 modes are obtained. Then, a spectra response analysis for each seismic event is carried out using ANSYS based on the modal analysis results. For each event, the obtained Tresca stress is evaluated to confirm the design integrity, by comparing the resulting stress to the design criteria. The Tresca strain and displacement are also estimated for the HCCR TBM-set. From the analysis, it was concluded that the maximum stresses by the seismic events meet the design criteria, and the displacements are lower than the designed gap from the TBM PP frame. The results are provided to a load combination analysis.
Critical seismic response of nuclear reactors
International Nuclear Information System (INIS)
Drenick, R.F.; Wang, P.C.; Yun, C.B.; Philappacopoulos, A.J.
1980-01-01
This paper deals with the problem of how to assess the seismic resistance of important structures, particularly of nuclear reactor structures. Most of the design procedures presently in use or under investigation are based on design response spectra obtained by statistical evaluation of past ground excitations assuming certain probability distributions (e.g., normal or lognormal) of response peaks. Artificial time histories generated from these spectra are also used. However, it is not clear whether these approaches lead to designs that can be relied upon on the confidence levels that are presumably desired for structures such as nuclear reactors whose integrity during an earthquake is of considerable importance. The trouble lies with the fact that the analysis of structural integrity seems highly sensitive to the assumptions regarding the nature of those probability distributions: small variations, especially in the tails of the distributions, can induce large changes in the desired results. This greatly weakens the reliance that can be placed in many assessments of earthquake resistance. In this paper, a new method is developed which has the potential of avoiding those weaknesses. It is more specifically based on assumptions that seem well supported by seismological observations but side-steps others, especially those regarding probability distribution of ground motions, which are more conjectural. (orig./RW)
Uncertainty analysis in seismic tomography
Owoc, Bartosz; Majdański, Mariusz
2017-04-01
Velocity field from seismic travel time tomography depends on several factors like regularization, inversion path, model parameterization etc. The result also strongly depends on an initial velocity model and precision of travel times picking. In this research we test dependence on starting model in layered tomography and compare it with effect of picking precision. Moreover, in our analysis for manual travel times picking the uncertainty distribution is asymmetric. This effect is shifting the results toward faster velocities. For calculation we are using JIVE3D travel time tomographic code. We used data from geo-engineering and industrial scale investigations, which were collected by our team from IG PAS.
Seismic Responses of Shot Span Bridge under Three Different Patterns of Earthquake Excitations
International Nuclear Information System (INIS)
Zhou Daochuan; Chen Guorong; Lu Yan
2010-01-01
This paper presents a study of the influence of three different types of seismic input methods on the longitudinal seismic response of a short, three-span, variable cross-section, reinforced concrete bridge. Research progress of the seismic model is introduced briefly. Finite element model is created for the bridge and time history analysis conducted. Three different types of illustrative excitations are considered: 1) the EI-Centro seismic wave is used as uniform excitations at all bridge supports; 2) fixed apparent wave velocity is used for response analysis of traveling wave excitations on the bridge; 3) conforming to a selected coherency model, the multiple seismic excitation time histories considering spatially variable effects are generated. The contrast study of the response analysis result under the three different seismic excitations is conducted and the influence of different seismic input methods is studied. The comparative analysis of the bridge model shows that the uniform ground motion input can not provide conservative seismic demands-in a number of cases it results in lower response than that predicted by multiple seismic excitations. The result of uniform excitation and traveling wave excitation shows very small difference. Consequently, multiple seismic excitations needs to be applied at the bridge supports for response analysis of short span bridge.
Factors affecting seismic response of submarine slopes
Directory of Open Access Journals (Sweden)
G. Biscontin
2006-01-01
Full Text Available The response of submerged slopes on the continental shelf to seismic or storm loading has become an important element in the risk assessment for offshore structures and 'local' tsunami hazards worldwide. The geological profile of these slopes typically includes normally consolidated to lightly overconsolidated soft cohesive soils with layer thickness ranging from a few meters to hundreds of meters. The factor of safety obtained from pseudo-static analyses is not always a useful measure for evaluating the slope response, since values less than one do not necessarily imply slope failure with large movements of the soil mass. This paper addresses the relative importance of different factors affecting the response of submerged slopes during seismic loading. The analyses use a dynamic finite element code which includes a constitutive law describing the anisotropic stress-strain-strength behavior of normally consolidated to lightly overconsolidated clays. The model also incorporates anisotropic hardening to describe the effect of different shear strain and stress histories as well as bounding surface principles to provide realistic descriptions of the accumulation of the plastic strains and excess pore pressure during successive loading cycles. The paper presents results from parametric site response analyses on slope geometry and layering, soil material parameters, and input ground motion characteristics. The predicted maximum shear strains, permanent deformations, displacement time histories and maximum excess pore pressure development provide insight of slope performance during a seismic event.
Seismic Analysis of a Viscoelastic Damping Isolator
Directory of Open Access Journals (Sweden)
Bo-Wun Huang
2015-01-01
Full Text Available Seismic prevention issues are discussed much more seriously around the world after Fukushima earthquake, Japan, April 2011, especially for those countries which are near the earthquake zone. Approximately 1.8×1012 kilograms of explosive energy will be released from a magnitude 9 earthquake. It destroys most of the unprotected infrastructure within several tens of miles in diameter from the epicenter. People can feel the earthquake even if living hundreds of miles away. This study is a seismic simulation analysis for an innovated and improved design of viscoelastic damping isolator, which can be more effectively applied to earthquake prevention and damage reduction of high-rise buildings, roads, bridges, power generation facilities, and so forth, from earthquake disaster. Solidworks graphic software is used to draw the 3D geometric model of the viscoelastic isolator. The dynamic behavior of the viscoelastic isolator through shock impact of specific earthquake loading, recorded by a seismometer, is obtained via ANSYS finite element package. The amplitude of the isolator is quickly reduced by the viscoelastic material in the device and is shown in a time response diagram. The result of this analysis can be a crucial reference when improving the design of a seismic isolator.
Russian regulatory approaches to seismic design and seismic analysis of NPP piping
International Nuclear Information System (INIS)
Kaliberda, Y.V.
2003-01-01
The paper presents an overview of Russian regulatory approaches to seismic design and seismic analysis of NPP piping. The paper is focused on categorization and seismic analysis of nuclear power plant items (piping, equipment, supports, valves, but not building structures). The paper outlines the current seismic recommendations, corresponding methods with the examples of calculation models. The paper considers calculation results of the mechanisms of dynamic behavior and the problems of developing a rational and economical approaches to seismic design and seismic protection. (author)
International Nuclear Information System (INIS)
Fogelquist, J.; Kaul, M.K.; Koppe, R.; Tagart, S.W. Jr.; Thailer, H.; Uffer, R.
1980-03-01
This project is directed toward a portion of the Seismic Safety Margins Research Program which includes one link in the seismic methodology chain. The link addressed here is the structural subsystem dynamic response which consists of those components and systems whose behavior is often determined decoupled from the major structural response. Typically the mathematical model utilized for the major structural response will include only the mass effects of the subsystem and the main model is used to produce the support motion inputs for subsystem seismic qualification. The main questions addressed in this report have to do with the seismic response uncertainty of safety-related components or equipment whose seismic qualification is performed by (a) analysis, (b) tests, or (c) combinations of analysis and tests, and where the seismic input is assumed to have no uncertainty
Seismic analysis of structures by simulation
International Nuclear Information System (INIS)
Sundararajan, C.; Gangadharan, A.C.
1977-01-01
The paper presents a state-of-the-art survey, and recommendations for future work in the area of stochastic seismic analysis by Monte Carlo simulation. First the Monte Carlo simulation procedure is described, with special emphasis on a 'unified approach' for the digital generation of artificial earthquake motions. Next, the advantages and disadvantages of the method over the power spectral method are discussed; and finally, an efficient 'Hybrid Monte Carlo-Power Spectral Method' is developed. The Monte Carlo simulation procedure consists of the following tasks: (1) Digital generation of artificial earthquake motions, (2) Response analysis of the structure to a number of sample motions, and (3) statistical analysis of the structural responses
Seismic analysis of structures by simulation
International Nuclear Information System (INIS)
Sundararajan, C.; Gangadharan, A.C.
1977-01-01
The paper presents a state-of-the-art survey, and recommendations for future work in the area of stochastic seismic analysis by Monte Carlo simulation. First the Monte Carlo simulation procedure is described with special emphasis on a 'unified approach' for the digital generation of anificial earthquake motions. Next, the advantages and disadvantages of the method over the power spectral method are discussed; and finally, an efficient 'Hybrid Monte Carlo-Power Spectral Method' is developed. The Monte Carlo simulation procedure consists of the following tasks: (1) Digital generation of artificial earthquake motions, (2) Response analysis of the structure to a number of sample motions, and (3) Statistical analysis of the structural responses. (Auth.)
Three-dimensional seismic analysis for spent fuel storage rack
International Nuclear Information System (INIS)
Lee, Gyu Mahn; Kim, Kang Soo; Park, Keun Bae; Park, Jong Kyun
1998-01-01
Time history analysis is usually performed to characterize the nonlinear seismic behavior of a spent fuel storage rack (SFSR). In the past, the seismic analyses of the SFSR were performed with two-dimensional planar models, which could not account for torsional response and simultaneous multi-directional seismic input. In this study, three-dimensional seismic analysis methodology is developed for the single SFSR using the ANSY code. The 3-D model can be used to determine the nonlinear behavior of the rack, i.e., sliding, uplifting, and impact evaluation between the fuel assembly and rack, and rack and the pool wall. This paper also reviews the 3-D modeling of the SFSR and the adequacy of the ANSYS for the seismic analysis. As a result of the adequacy study, the method of ANSYS transient analysis with acceleration time history is suitable for the seismic analysis of highly nonlinear structure such as an SFSR but it isn't appropriate to use displacement time history of seismic input. (author)
Recent Vs. Historical Seismicity Analysis For Banat Seismic Region (Western Part Of Romania)
Oros Eugen; Diaconescu Mihai
2015-01-01
The present day seismic activity from a region reflects the active tectonics and can confirm the seismic potential of the seismogenic sources as they are modelled using the historical seismicity. This paper makes a comparative analysis of the last decade seismicity recorded in the Banat Seismic Region (western part of Romania) and the historical seismicity of the region (Mw≥4.0). Four significant earthquake sequences have been recently localized in the region, three of them nearby the city of...
Seismic response and rehabilitation of critical substation equipment
Energy Technology Data Exchange (ETDEWEB)
Saadeghvaziri, M.A.; Allaverdi, N.H. [New Jersey Inst. of Technology, Newark, NJ (United States); Ashrafi, A. [Columbia Univ., New York, NY (United States); Ersoy, S. [Greenman-Pedersen Inc., Babylon, NY (United States)
2004-07-01
Substations are one of the most important components of an electrical power system. They provide protection to transmission and distribution lines and transfer power between different voltage levels. Transformers and bushings within the substation are vulnerable to earthquake ground motion. It is extremely important that electric power systems remain functional following seismic damage. This study assessed the seismic response of critical substation equipment and described advanced technologies for rehabilitation measures such as the Friction Pendulum System (FPS). It presents the results of an extensive finite element analysis on response of transformers and bushings. The objective was to determine the seismic behaviour of transformers and bushings during an earthquake and to determine the probability of different failure modes. The response of an FPS isolated transformer to different earthquakes was also examined along with FPS radii, ground motion intensity and vertical excitations. A finite element model was developed for FPS. The study showed that seismic isolation is a viable mitigation strategy, but a modest increase in slack must be provided. 15 refs., 1 tab., 12 figs.
Probabilistic Seismic Hazard Analysis for Yemen
Directory of Open Access Journals (Sweden)
Rakesh Mohindra
2012-01-01
Full Text Available A stochastic-event probabilistic seismic hazard model, which can be used further for estimates of seismic loss and seismic risk analysis, has been developed for the territory of Yemen. An updated composite earthquake catalogue has been compiled using the databases from two basic sources and several research publications. The spatial distribution of earthquakes from the catalogue was used to define and characterize the regional earthquake source zones for Yemen. To capture all possible scenarios in the seismic hazard model, a stochastic event set has been created consisting of 15,986 events generated from 1,583 fault segments in the delineated seismic source zones. Distribution of horizontal peak ground acceleration (PGA was calculated for all stochastic events considering epistemic uncertainty in ground-motion modeling using three suitable ground motion-prediction relationships, which were applied with equal weight. The probabilistic seismic hazard maps were created showing PGA and MSK seismic intensity at 10% and 50% probability of exceedance in 50 years, considering local soil site conditions. The resulting PGA for 10% probability of exceedance in 50 years (return period 475 years ranges from 0.2 g to 0.3 g in western Yemen and generally is less than 0.05 g across central and eastern Yemen. The largest contributors to Yemen’s seismic hazard are the events from the West Arabian Shield seismic zone.
Seismic analysis of liquid metal fast breeder reactors
International Nuclear Information System (INIS)
Gilbert, R.J.; Martelli, A.
1989-06-01
This report is a general survey of the recent methods to predict the seismic structural behaviour of LMFBRs. It shall put into evidence the impact of seismic analysis on the design of the different structures of the reactor. This report is addressed to specialists and institutions of governmental organizations in industrialized and developing countries responsible for the design and operation of LMFBRs. The information presented should enable specialists in the R and D institutions and industries likely to be involved, to establish the correct course of the design and operation of LMFBRs. Also, the safety aspect of seismic risk are emphasized in the report. Refs and figs
Seismic response of reinforced soil slopes
DEFF Research Database (Denmark)
Tzavara, Ioanna; Zania, Varvara; Tsompanakis, Yiannis
2010-01-01
The main aim of the current study is to assess the dynamic response of reinforced soil structures taking into account the most important aspects of the problem and to compare the available design methods. For this purpose, initially the most commonly used pseudostatic approach is implemented via...... a parametric investigation to illustrate the impact of the crucial parameters of this approach. Subsequently, Newmark’s sliding block model is modified to account for the reinforcement forces in the calculation of seismic displacements. Finally, finite element analyses were performed and the numerical results...
Seismic analysis of freestanding fuel racks
International Nuclear Information System (INIS)
Gilmore, C.B.
1982-01-01
This paper presents a nonlinear transient dynamic time-history analysis of freestanding spent fuel storage racks subjected to seismic excitation. This type of storage rack is structurally unrestrained and submerged in water in the spent fuel pool of a nuclear power complex, holds (spent) fuel assemblies which have been removed from the reactor core. Nonlinearities in the fuel rack system include impact between the fuel assembly and surrounding cell due to clearances between them, friction due to sliding between the fuel rack support structure and spent fuel pool floor, and the lift-off of the fuel rack support structure from the spent fuel pool floor. The analysis of the fuel rack system includes impacting due to gap closures, energy losses due to impacting bodies, Coulomb damping between sliding surfaces, and hydrodynamic mass effects. Acceleration time history excitation development is discussed. Modeling considerations, such as the initial status of nonlinear elements, number of mode shapes to include in the analysis, modal damping, and integration time-step size are presented. The response of the fuel rack subjected to two-dimensional seismic excitation is analyzed by the modal superposition method, which has resulted in significant computer cost savings when compared to that of direct integration
Seismic response of base isolated auxiliary building with age related degradation
International Nuclear Information System (INIS)
Park, Jun Hee; Choun, Young Sun; Choi, In Kil
2012-01-01
The aging of an isolator affects not only the mechanical properties of the isolator but also the dynamic properties of the upper structure, such as the change in stiffness, deformation capacity, load bearing capacity, creep, and damping. Therefore, the seismic response of base isolated structures will change with time. The floor response in the base isolated nuclear power plants (NPPs) can be particularly changed because of the change in stiffness and damping for the isolator. The increased seismic response due to the aging of isolator can cause mechanical problems for many equipment located in the NPPs. Therefore, it is necessary to evaluate the seismic response of base isolated NPPs with age related degradation. In this study, the seismic responses for a base isolated auxiliary building of SHIN KORI 3 and 4 with age related degradation were investigated using a nonlinear time history analysis. Floor response spectrums (FRS) were presented with time for identifying the change in seismic demand under the aging of isolator
Seismic analysis and design of NPP structures
International Nuclear Information System (INIS)
de Carvalho Santos, S.H.; da Silva, R.E.
1989-01-01
Numerical methods for static and dynamic analysis of structures, as well as for the design of individual structural elements under the applied loads are under continuous development, being very sophisticated methods nowadays available for the engineering practice. Nevertheless, this sophistication will be useless if some important aspects necessary to assure full compatability between analysis and design are disregarded. Some of these aspects are discussed herein. This paper presents an integrated approach for the seismic analysis and design of NPP structures: the development of models for the seismic analysis, the distribution of the global seismic forces among the seismic-resistant elements and the criteria for the design of the individual elements for combined static and dynamic forces are the main topics to be discussed herein. The proposed methodology is illustrated. Some examples taken from the project practice are presented for illustration the exposed concepts
Seismic response of cable stayed bridges under multi support excitation
Directory of Open Access Journals (Sweden)
Mahmoud Reza ُُShiravand
2017-07-01
Full Text Available In this Study, the seismic response of cable stayed bridges have been evaluated under multi-support excitations. There are three sources that cause the earthquake wave characteristics change during its propagation path. Local site effect, loss of coherency and wave passage effect are three sources of spatial variation of seismic ground motions. In long span structures, such as cable supported bridges, this phenomenon is more evident and traditional analyzing (uniform excitation may not be valid and be conservative. Thus, it is necessary to investigate the response of cable stayed bridges under non-uniform excitations. For this purpose, the non-uniform time histories were artificially generated using Kriging method based on a set of known time history in the west support of bridge. Nonlinear time history analysis was performed and cables axial force, deck moment, pylons moment and finally drift ratio of bridge have been examined in order to investigate how non-uniform excitation change the seismic response of bridge compared with uniform excitations. Results show non-uniform excitation in some bridge components increase responses and decreases in the others. In non-uniform excitation, although total time history energy is lesser than uniform excitation, it can significantly change the distribution of the forces and makes differential displacement between cables supports and increase the possibility of failure.
Dynamic response of Belene WWER-1000 to seismic loading conditions
International Nuclear Information System (INIS)
Krutzik, N.J.; Petrovski, D.; Sachanski, S.
1993-01-01
Within the framework of investigating of the capacity of the WWER-100 at the Belene site, an analysis was performed using revised seismic input data as well as two alternative foundation concepts (natural soil and soil exchange). The starting point for the analysis was the development of a suitable model of the coupled structures (base building, external building, containment, internal structure) and soil taking into account the real properties of the originally layered as well as the exchanged soil. The soil-structure effects were considered according to the analytical method employed, either through soil impedance (substructure method) or explicitly by a complex (direct method). On the basis of the results obtained by the two methods (substructure and direct method) the seismic safety of the complex structures for different foundation concepts was evaluated. By comparing the calculated structural response with the design spectra originally used for the design of components and systems the available safety margin was estimated
HANFORD DOUBLE SHELL TANK THERMAL AND SEISMIC PROJECT SEISMIC ANALYSIS OF HANFORD DOUBLE SHELL TANKS
Energy Technology Data Exchange (ETDEWEB)
MACKEY TC; RINKER MW; CARPENTER BG; HENDRIX C; ABATT FG
2009-01-15
M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratories (PNNL) to perform seismic analysis of the Hanford Site Double-Shell Tanks (DSTs) in support of a project entitled Double-Shell Tank (DST) Integrity Project - DST Thermal and Seismic Analyses. The original scope of the project was to complete an up-to-date comprehensive analysis of record of the DST System at Hanford in support of Tri-Party Agreement Milestone M-48-14. The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). Although Milestone M-48-14 has been met, Revision I is being issued to address external review comments with emphasis on changes in the modeling of anchor bolts connecting the concrete dome and the steel primary tank. The work statement provided to M&D (PNNL 2003) required that a nonlinear soil structure interaction (SSI) analysis be performed on the DSTs. The analysis is required to include the effects of sliding interfaces and fluid sloshing (fluid-structure interaction). SSI analysis has traditionally been treated by frequency domain computer codes such as SHAKE (Schnabel, et al. 1972) and SASSI (Lysmer et al. 1999a). Such frequency domain programs are limited to the analysis of linear systems. Because of the contact surfaces, the response of the DSTs to a seismic event is inherently nonlinear and consequently outside the range of applicability of the linear frequency domain programs. That is, the nonlinear response of the DSTs to seismic excitation requires the use of a time domain code. The capabilities and limitations of the commercial time domain codes ANSYS{reg_sign} and MSC Dytran{reg_sign} for performing seismic SSI analysis of the DSTs and the methodology required to perform the detailed seismic analysis of the DSTs has been addressed in Rinker et al (2006a). On the basis of the results reported in Rinker et al
Directory of Open Access Journals (Sweden)
SEDIN V. L.
2015-11-01
Full Text Available Problem statement. Providing of safe exploitation of nuclear power plants, as well as a safety of staff and environment is a very important problem. A distinct feature of this problem is a necessity to provide not only a strength of structures, but also a safe functioning of all systems that control nuclear process. In particular, the influence of earthquake should be considered on constructions of buildings and structures of nuclear and thermal power plant, taking into account soil-structure interaction. According to IAEA’s SSD-9 recommendations, a risk of vibration of soil should be analyzed for each NPP connected with earthquakes soil that means researches, including general, detailed and microseismic zoning of the area works. One of the distinctive features of the considered problem is an evaluation of the seismicity of area and getting the response spectrum on the free surface. Purpose. Determination of seismic resistance of buildings of high category of safety with the example of the reactor compartment of Zaporoghskaya NPP including the soil structure interaction. Conclusion The seismicity assessment of the area and obtaining of response specters on free surface was made during research and analysis of seismic resistance of buildings of high category of safety including the effects of foundation and structures. The method of modeling of the equivalent dynamic characteristics of the base was considered during the research in seismic impacts.
Energy Technology Data Exchange (ETDEWEB)
Ryu, Jeong Soo; Yoon, Doo Byung
2003-06-01
The HANARO SMAS(Seismic Monitoring Analysis System) is classified as Non-Nuclear Safety(NNS), seismic category I, and quality class T. It is required that this system can perform required functions, which are to preserve its structural integrity during and after an OBE or SSE. In this work, the structural integrity and seismic characteristics of the cabinet of the newly developed SMAS have been estimated. The most parts of the cabinet are identically designed with those of Yonggwhang and Gori Nuclear Power Plants(NPPs), unit 1 that successfully completed the required seismic qualification tests. The structure of the cabinet of the SMAS is manufactured by the manufacturer of the cabinet of Yonggwhang and Gori NPPs. To evaluate the seismic characteristics of the SMAS, the RRS(Required Response Spectra) of the newly developed cabinet are compared with those of Yonggwhang and Gori NPPs, unit 1. In addition, natural frequencies of the cabinet of HANARO, Yonggwhang, and Gori NPPs were measured for the comparison of the seismic characteristics of the installed cabinets. In case of HANARO, the bottom of the cabinet is welded to the base plate. The base plate is fixed to the concrete foundation by using anchor bolts. For the evaluation of the structural integrity of the welding parts and the anchor bolts, the maximum stresses and forces of the welding parts and the anchor bolts due to seismic loading are estimated. The analysis results show that maximum stresses and forces are less than the allowable limits. This new SMAS is operating at HANARO instrument room to acquire and analyze the signal of earthquake.
International Nuclear Information System (INIS)
Namita, Yoshio; Kawahata, Jun-ichi; Ichihashi, Ichiro; Fukuda, Toshihiko.
1995-01-01
Component and piping systems in current nuclear power plants and chemical plants are designed to employ many supports to maintain safety and reliability against earthquakes. However, these supports are rigid and have a slight energy-dissipating effect. It is well known that applying high-damping supports to the piping system is very effective for reducing the seismic response. In this study, we investigated the design method of the elastoplastic damper [energy absorber (EAB)] and the seismic design method for a piping system supported by the EAB. Our final goal is to develop technology for applying the EAB to the piping system of an actual plant. In this paper, the vibration test results of the three-dimensional piping model are presented. From the test results, it is confirmed that EAB has a large energy-dissipating effect and is effective in reducing the seismic response of the piping system, and that the seismic design method for the piping system, which is the response spectrum mode superposition method using each modal damping and requires iterative calculation of EAB displacement, is applicable for the three-dimensional piping model. (author)
Reanalysis and evaluation of seismic response of reactor building
International Nuclear Information System (INIS)
Li Zhongcheng; Li Zhongxian
2005-01-01
For the Ling Ao phase-I (LA-I) Nuclear Power Plant (NPP), its' seismic analysis of nuclear island was in accordance with the approaches in RCC-G standard for the model M310 in France, in which the Simplified impedance method was employed for the consideration of SSI. Thanks to the rapid progress being made in upgrading the evaluation technology and the capability of data processing systems, methods and software tools for the SSI analysis have experienced significant development all over the world. Focused on the model of reactor building of the LA-I NPP, in this paper the more sophisticated 3D half-space continuum impedance method based on the Green functions is used to analyze the functions of the soil, and then the seismic responses of the coupled SSI system are calculated and compared with the corresponding design values. It demonstrates that the design method provides a set of conservatively safe results. The conclusions from the study are hopefully to provide some important references to the assessment of seismic safety margin for LA-I NPP. (authors)
Seismic analysis of plutonium glovebox by MSC/NASTRAN
International Nuclear Information System (INIS)
Hirata, Masaru; Ishikawa, Kazuya; Korosawa, Makoto; Fukushima, Susumu; Hoshina, Hirofumi.
1993-01-01
Seismic analysis of the structural strength of gloveboxes is important for plutonium confinement evaluation. However, the analytical methods must be developed for evaluating the mutual displacement between the window frame and acrylic resin window panel with regard to plutonium confinement during an earthquake. Therefore, seismic analysis for a standard glovebox in Plutonium Fuel Research Facility at Oarai Research Establishment of JAERI has been conducted by FEM (Finite Element Method) computer code MSC/NASTRAN (MacNeal-Schwendler Corporation NASA Structural Analysis). Modelling of glovebox window frame has been investigated from the results of natural frequency analysis and static analysis. After the acquisition of a suitable model, displacement around the window frame and glovebox structural strength have been evaluated in detail by use of floor response spectrum analysis and time-history (transient response) analysis. (author)
Assessment of seismic design response factors of concrete wall buildings
Mwafy, Aman
2011-03-01
To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region (UAE). A large number of Inelastic Pushover Analyses (IPAs) and Incremental Dynamic Collapse Analyses (IDCAs) were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.
Seismic analysis of a reactor building with eccentric layout
International Nuclear Information System (INIS)
Itoh, T.; Deng, D.Z.F.; Lui, K.
1987-01-01
Conventional design for a reactor building in a high seismic area has adopted an essentially concentric layout in response to fear of excessive torsional effect due to horizontal seismic load on an eccentric plant. This concentric layout requirement generally results in an inflexible arrangement of the plant facilities and thus increases the plant volume. This study is performed to investigate the effect of eccentricity on the overall seismic structural response and to provide technical information in this regard to substantiate the volume reduction of the overall power plant. The plant layout is evolved from the Bechtel standard plan of a PWR plant by integrating the reactor building and the auxiliary building into a combined building supported on a common basemat. This plant layout is optimized for volume utilization and to reduce the length of piping systems. The mass centers at various elevations of the combined building do not coincide with the rigidity center (RC) of the respective floor and the geometric center of the basemat, thus creating an eccentric response of the building in a seismic environment. Therefore, the torsional effects of the structure have to be taken into account in the seismic analysis
Seismic analysis of fast breeder reactor block
International Nuclear Information System (INIS)
Gantenbein, F.
1990-01-01
Seismic analysis of LMFBR reactor block is complex due mainly to the fluid structure interaction and the 3D geometry of the structure. Analytical methods which have been developed for this analysis will be briefly described in the paper and applications to a geometry similar to SPX1 will be shown
Modeling of seismic hazards for dynamic reliability analysis
International Nuclear Information System (INIS)
Mizutani, M.; Fukushima, S.; Akao, Y.; Katukura, H.
1993-01-01
This paper investigates the appropriate indices of seismic hazard curves (SHCs) for seismic reliability analysis. In the most seismic reliability analyses of structures, the seismic hazards are defined in the form of the SHCs of peak ground accelerations (PGAs). Usually PGAs play a significant role in characterizing ground motions. However, PGA is not always a suitable index of seismic motions. When random vibration theory developed in the frequency domain is employed to obtain statistics of responses, it is more convenient for the implementation of dynamic reliability analysis (DRA) to utilize an index which can be determined in the frequency domain. In this paper, we summarize relationships among the indices which characterize ground motions. The relationships between the indices and the magnitude M are arranged as well. In this consideration, duration time plays an important role in relating two distinct class, i.e. energy class and power class. Fourier and energy spectra are involved in the energy class, and power and response spectra and PGAs are involved in the power class. These relationships are also investigated by using ground motion records. Through these investigations, we have shown the efficiency of employing the total energy as an index of SHCs, which can be determined in the time and frequency domains and has less variance than the other indices. In addition, we have proposed the procedure of DRA based on total energy. (author)
Seismic analysis of ITER fourth PF (Poloidal Field Coil) feeder
International Nuclear Information System (INIS)
Liu, Sumei; Chen, Wei; Song, Yuntao; Ni, Xiaojun; Wang, Zhongwei; Chen, Yonghua; Gong, Chenyu
2014-01-01
The ITER feeder systems connect the ITER magnet systems located inside the main cryostat to the cryo-plant, power-supply and control system interfaces outside the cryostat. The main purpose of the feeders is to convey the cryogenic supply and electrical power to the coils as well as house the instrumentation wiring. The PF busbar which carries 52 kA current will suffer from high Lorentz force due to the background magnetic field inspired by the coils and the self-field between every pair of busbars. Except their mechanical strength and thermal insulation performance must be achieved, the dynamic mechanism on PF structure should be assessed. This paper presents the simulation and seismic analysis on ITER 4th PF feeder including the Coil Terminal Box and S-bend Box (CTB and SBB), the Cryostat Feed-through (CFT), the In-Cryostat-Feeder (ICF), especially for the ground supports and main outer-tube firstly. This analysis aims to study seismic resistance on system design under local seismograms with floor response spectrum, the structural response vibration mode and response duration results of displacement, membrane stress, and bending stress on structure under different directions actuating signals were obtained by using the single-seismic spectrum analysis and Dead Weight analysis respectively. Based on the simulative and analytical results, the system seismic resistance and the integrity of the support structure in the 4th PF feeder have been studied and the detail design confirmed
Sensitivity Analysis on Elbow Piping Components in Seismically Isolated NPP under Seismic Loading
Energy Technology Data Exchange (ETDEWEB)
Ju, Hee Kun; Hahm, Dae Gi; Kim, Min Kyu [KAERI, Daejeon (Korea, Republic of); Jeon, Bub Gyu; Kim, Nam Sik [Pusan National University, Busan (Korea, Republic of)
2016-05-15
In this study, the FE model is verified using specimen test results and simulation with parameter variations are conducted. Effective parameters will randomly sampled and used as input values for simulations to be applied to the fragility analysis. pipelines are representative of them because they could undergo larger displacements when they are supported on both isolated and non-isolated structures simultaneously. Especially elbows are critical components of pipes under severed loading conditions such as earthquake action because strain is accumulated on them during the repeated bending of the pipe. Therefore, seismic performance of pipe elbow components should be examined thoroughly based on the fragility analysis. Fragility assessment of interface pipe should take different sources of uncertainty into account. However, selection of important sources and repeated tests with many random input values are very time consuming and expensive, so numerical analysis is commonly used. In the present study, finite element (FE) model of elbow component will be validated using the dynamic test results of elbow components. Using the verified model, sensitivity analysis will be implemented as a preliminary process of seismic fragility of piping system. Several important input parameters are selected and how the uncertainty of them are apportioned to the uncertainty of the elbow response is to be studied. Piping elbows are critical components under cyclic loading conditions as they are subjected large displacement. In a seismically isolated NPP, seismic capacity of piping system should be evaluated with caution. Seismic fragility assessment preliminarily needs parameter sensitivity analysis about the output of interest with different input parameter values.
Energy Technology Data Exchange (ETDEWEB)
MACKEY, T.C.
2006-03-17
M&D Professional Services, Inc. (M&D) is under subcontract to Pacific Northwest National Laboratory (PNNL) to perform seismic analysis of the Hanford Site double-shell tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project--DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST system at Hanford in support of Tri-Party Agreement Milestone M-48-14, The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). The work statement provided to M&D (PNNL 2003) required that the seismic analysis of the DSTs assess the impacts of potentially non-conservative assumptions in previous analyses and account for the additional soil mass due to the as-found soil density increase, the effects of material degradation, additional thermal profiles applied to the full structure including the soil-structure response with the footings, the non-rigid (low frequency) response of the tank roof, the asymmetric seismic-induced soil loading, the structural discontinuity between the concrete tank wall and the support footing and the sloshing of the tank waste. The seismic analysis considers the interaction of the tank with the surrounding soil and the effects of the primary tank contents. The DSTs and the surrounding soil are modeled as a system of finite elements. The depth and width of the soil incorporated into the analysis model are sufficient to obtain appropriately accurate analytical results. The analyses required to support the work statement differ from previous analysis of the DSTs in that the soil-structure interaction (SSI) model includes several (nonlinear) contact surfaces in the tank structure, and the contained waste must be modeled explicitly in order to capture the fluid-structure interaction behavior between the primary
A Seismic Analysis for Reflective Metal Insulation
Energy Technology Data Exchange (ETDEWEB)
Kim, Kyuhyung; Kim, Taesoon [KHNP CRI, Daejeon (Korea, Republic of)
2016-10-15
U.S. NRC (Nuclear Regulatory Commission) GSI- 191 (Generic Safety Issue-191) is concerned about the head-loss of emergency core cooling pumps caused by calcium silicate insulation debris accumulated on a sump screen when a loss of coolant accident (LOCA). In order to cope with the concern, many nuclear plants in U. S. have been replacing calcium silicate insulation in containment building with reflective metal insulation (RMI). In Korea, RMI has been used for only reactor vessels recently constructed, but the RMI was imported. Therefore, we have been developing the domestic design of RMI to supply to nuclear power plants under operation and construction in relation to the GSI-191. This paper covers that the structural integrity of the RMI assembly was evaluated under SSE (safety shutdown earthquake) load. An analysis model was built for the seismic test system of a reflective metal insulation assembly and pre-stress, modal, and spectrum analysis for the model were performed using a commercial structural analysis code, ANSYS. According to the results of the analyses, the buckles fastening the RMIs showed the structural integrity under the required response spectrum containing the safety shutdown earthquake loads applied to main components in containment building. Consequently, since the RMI isn't disassembled under the SSE load, the RMI is judged not to affect safety related components.
A Seismic Analysis for Reflective Metal Insulation
International Nuclear Information System (INIS)
Kim, Kyuhyung; Kim, Taesoon
2016-01-01
U.S. NRC (Nuclear Regulatory Commission) GSI- 191 (Generic Safety Issue-191) is concerned about the head-loss of emergency core cooling pumps caused by calcium silicate insulation debris accumulated on a sump screen when a loss of coolant accident (LOCA). In order to cope with the concern, many nuclear plants in U. S. have been replacing calcium silicate insulation in containment building with reflective metal insulation (RMI). In Korea, RMI has been used for only reactor vessels recently constructed, but the RMI was imported. Therefore, we have been developing the domestic design of RMI to supply to nuclear power plants under operation and construction in relation to the GSI-191. This paper covers that the structural integrity of the RMI assembly was evaluated under SSE (safety shutdown earthquake) load. An analysis model was built for the seismic test system of a reflective metal insulation assembly and pre-stress, modal, and spectrum analysis for the model were performed using a commercial structural analysis code, ANSYS. According to the results of the analyses, the buckles fastening the RMIs showed the structural integrity under the required response spectrum containing the safety shutdown earthquake loads applied to main components in containment building. Consequently, since the RMI isn't disassembled under the SSE load, the RMI is judged not to affect safety related components
Seismic analysis of large pools
Energy Technology Data Exchange (ETDEWEB)
Dong, R.G.; Tokarz, F.J.
1976-11-17
Large pools for storing spent, nuclear fuel elements are being proposed to augment present storage capacity. To preserve the ability to isolate portions of these pools, a modularization requirement appears desirable. The purpose of this project was to investigate the effects of modularization on earthquake resistance and to assess the adequacy of current design methods for seismic loads. After determining probable representative pool geometries, three rectangular pool configurations, all 240 x 16 ft and 40 ft deep, were examined. One was unmodularized; two were modularized into 80 x 40 ft cells in one case and 80 x 80 ft cells in the other. Both embedded and above-ground installations for a hard site and embedded installations for an intermediate hard site were studied. It was found that modularization was unfavorable in terms of reducing the total structural load attributable to dynamic effects, principally because one or more cells could be left unfilled. The walls of unfilled cells would be subjected to significantly higher loads than the walls of a filled, unmodularized pool. Generally, embedded installations were preferable to above-ground installations, and the hard site was superior to the intermediate hard site. It was determined that Housner's theory was adequate for calculating hydrodynamic effects on spent fuel storage pools. Current design methods for seismic loads were found to be satisfactory when results from these methods were compared with those from LUSH analyses. As a design method for dynamic soil pressure, we found the Mononobe-Okabe theory, coupled with correction factors as suggested by Seed, to be acceptable. The factors we recommend for spent fuel storage pools are tabulated.
Seismic analysis of large pools
International Nuclear Information System (INIS)
Dong, R.G.; Tokarz, F.J.
1976-01-01
Large pools for storing spent, nuclear fuel elements are being proposed to augment present storage capacity. To preserve the ability to isolate portions of these pools, a modularization requirement appears desirable. The purpose of this project was to investigate the effects of modularization on earthquake resistance and to assess the adequacy of current design methods for seismic loads. After determining probable representative pool geometries, three rectangular pool configurations, all 240 x 16 ft and 40 ft deep, were examined. One was unmodularized; two were modularized into 80 x 40 ft cells in one case and 80 x 80 ft cells in the other. Both embedded and above-ground installations for a hard site and embedded installations for an intermediate hard site were studied. It was found that modularization was unfavorable in terms of reducing the total structural load attributable to dynamic effects, principally because one or more cells could be left unfilled. The walls of unfilled cells would be subjected to significantly higher loads than the walls of a filled, unmodularized pool. Generally, embedded installations were preferable to above-ground installations, and the hard site was superior to the intermediate hard site. It was determined that Housner's theory was adequate for calculating hydrodynamic effects on spent fuel storage pools. Current design methods for seismic loads were found to be satisfactory when results from these methods were compared with those from LUSH analyses. As a design method for dynamic soil pressure, we found the Mononobe-Okabe theory, coupled with correction factors as suggested by Seed, to be acceptable. The factors we recommend for spent fuel storage pools are tabulated
Seismic response of a block-type nuclear reactor core
International Nuclear Information System (INIS)
Dove, R.C.; Bennett, J.G.; Merson, J.L.
1976-05-01
An analytical model is developed to predict seismic response of large gas-cooled reactor cores. The model is used to investigate scaling laws involved in the design of physical models of such cores, and to make parameter studies
A random probabilistic approach to seismic nuclear power plant analysis
International Nuclear Information System (INIS)
Romo, M.P.
1985-01-01
A probabilistic method for the seismic analysis of structures which takes into account the random nature of earthquakes and of the soil parameter uncertainties is presented in this paper. The method was developed combining elements of the theory of perturbations, the Random vibration theory and the complex response method. The probabilistic method is evaluated by comparing the responses of a single degree of freedom system computed with this approach and the Monte Carlo method. (orig.)
Instantaneous response spectrum in seismic testing of nuclear power plant equipment
International Nuclear Information System (INIS)
Morrone, A.
1977-01-01
Seismic response spectra, as used in seismic analyses, give the maximum responses of single degree of freedom oscillators without consideration of the different time in the seismic time history at which each of the maximum responses occur. For response spectrum seismic analysis, the use of time-independent maximum responses is appropriate. The time dependece is considered in a statistical manner, for multi-degree of freedom systems, usually by combining the modal effects by the square root of the sum of the squares. For seismic testing of electrical equipment. IEEE Std. 344-1975 makes use of the response spectrum to define the input motion of the shake table. One of the basic requirements is that the test response spectrum (TRS) that is, the response spectrum produced by the shake table motion, should envelop the required response spectrum (RRS) calculated from the building analysis at the support point of the equipment being tested. This paper presents the concept of instantaneous response spectrum (IRS) as the response of single degree of freedom oscillators at a particular time. It demonstrates that a shake table random motion whose standard TRS envelops the RRS does not necessarily satisfy the enveloping requirement instantaneously. (Auth.)
Pilz, Marco; Parolai, Stefano; Leyton, Felipe; Campos, Jaime; Zschau, Jochen
2009-08-01
Situated in an active tectonic region, Santiago de Chile, the country's capital with more than six million inhabitants, faces tremendous earthquake risk. Macroseismic data for the 1985 Valparaiso event show large variations in the distribution of damage to buildings within short distances, indicating strong effects of local sediments on ground motion. Therefore, a temporary seismic network was installed in the urban area for recording earthquake activity and a study was carried out aiming to estimate site amplification derived from horizontal-to-vertical (H/V) spectral ratios from earthquake data (EHV) and ambient noise (NHV), as well as using the standard spectral ratio (SSR) technique with a nearby reference station located on igneous rock. The results lead to the following conclusions: (1) The analysis of earthquake data shows significant dependence on the local geological structure with respect to amplitude and duration. (2) An amplification of ground motion at frequencies higher than the fundamental one can be found. This amplification would not be found when looking at NHV ratios alone. (3) The analysis of NHV spectral ratios shows that they can only provide a lower bound in amplitude for site amplification. (4) P-wave site responses always show lower amplitudes than those derived by S waves, and sometimes even fail to provide some frequencies of amplification. (5) No variability in terms of time and amplitude is observed in the analysis of the H/V ratio of noise. (6) Due to the geological conditions in some parts of the investigated area, the fundamental resonance frequency of a site is difficult to estimate following standard criteria proposed by the SESAME consortium, suggesting that these are too restrictive under certain circumstances.
Kinematic seismic response of piles in layered soil profile
International Nuclear Information System (INIS)
Ahmad, I.; Khan, A.N.
2006-01-01
This paper is aimed at highlighting the importance of Kinematic Seismic Response of Piles, a phenomenon often ignored in dynamic analysis. A case study is presented where the end bearing pile is embedded in two layer soil system of highly contrasting stiffnesses; a typical case where kinematic loading plays important role. The pile soil system is modeled as continuous system and as discrete parameter system; both are based on BDWF (Beam on Dynamic Winkler Foundation) formulation. For discrete parameter system, a finite element software SAP2000 is used and the modeling technique of kinematic interaction in finite element software is discussed. For pile soil system modeled as continuous system, a general MATLAB code is developed capable of performing elastic site response analysis in two layer soil system, solving differential equation governing kinematic interaction, and giving as output the maximum ground displacement, maximum pile displacement, rotation, moment and shear distribution along pile length. The paper concludes that kinematic seismic actions must be evaluated particularly at the interface of soil layers of significantly differing soil stiffnesses. (author)
Stochastic seismic response of building with super-elastic damper
Gur, Sourav; Mishra, Sudib Kumar; Roy, Koushik
2016-05-01
Hysteretic yield dampers are widely employed for seismic vibration control of buildings. An improved version of such damper has been proposed recently by exploiting the superelastic force-deformation characteristics of the Shape-Memory-Alloy (SMA). Although a number of studies have illustrated the performance of such damper, precise estimate of the optimal parameters and performances, along with the comparison with the conventional yield damper is lacking. Presently, the optimal parameters for the superelastic damper are proposed by conducting systematic design optimization, in which, the stochastic response serves as the objective function, evaluated through nonlinear random vibration analysis. These optimal parameters can be employed to establish an initial design for the SMA-damper. Further, a comparison among the optimal responses is also presented in order to assess the improvement that can be achieved by the superelastic damper over the yield damper. The consistency of the improvements is also checked by considering the anticipated variation in the system parameters as well as seismic loading condition. In spite of the improved performance of super-elastic damper, the available variant of SMA(s) is quite expensive to limit their applicability. However, recently developed ferrous SMA are expected to offer even superior performance along with improved cost effectiveness, that can be studied through a life cycle cost analysis in future work.
Seismic response of flexible cylindrical tanks
Energy Technology Data Exchange (ETDEWEB)
Jaeger, T A; Boley, B A [comps.
1977-01-01
An experimental study of the seismic behavior of thin shell circular cylindrical liquid storage tanks is described. The investigation was planned to evaluate the adequacy of present methods of tank design, and was conducted using the Earthquake Simulator Facility of the University of California, Berkeley. The model tank considered in this paper was 6 ft high by 12 ft in diameter, and was welded from thin sheet aluminum to simulate a steel tank 36 feet in diameter. During testing the tank had an open top, held 60 inches of water, and was subjected to a time scaled El Centro (1940) earthquake, amplified to a peak acceleration of 0.5 g. Both base free and base fixed conditions were studied. Results of the experiments demonstrate that fluid pressures included both impulsive and convective components, and that the wave sloshing followed basic theory quite closely. But it also was apparent that the tank flexibility influenced the hydrodynamic pressures, as indicated by pressure amplification in the clamped tank, and by a total change of pressure history in the unclamped case. Significant out of round distortions of the tank were developed, of a three lobe form or the free base case and with four lobes in the fixed base case. Uplift of the tank base was closely related to the out-of-round deformation of the unanchored tank, whereas initial eccentricities apparently caused the section distortions in the anchored system. Stresses in the tank wall do not follow the expected pattern of response to overturning moment; instead they seem to be mainly associated with the section distortions. At present there is no analytical procedure for predicting these distortions .
Energy Technology Data Exchange (ETDEWEB)
Lee, J. H.; Yoo, B.; Koo, K. H. [KAERI, Taejon (Korea, Republic of)
2001-05-01
The seismic response time history analyses for the lumped mass models of KALIMER reactor building with a horizontal and vertical seismic isolation are performed for Artificial Time History and Kobe earthquake. The vertical amplification by the horizontal isolation is reduced by a vertical isolation for both earthquakes. The 3% viscous damping and the vertical isolation frequency of 1.5Hz gives a reduced vertical response compared to the fixed base condition at reactor support, and the 9% viscous damping to Kobe earthquake is required to get an equivalent vertical response with a fixed base condition.
International Nuclear Information System (INIS)
Lee, J. H.; Yoo, B.; Koo, K. H.
2001-01-01
The seismic response time history analyses for the lumped mass models of KALIMER reactor building with a horizontal and vertical seismic isolation are performed for Artificial Time History and Kobe earthquake. The vertical amplification by the horizontal isolation is reduced by a vertical isolation for both earthquakes. The 3% viscous damping and the vertical isolation frequency of 1.5Hz gives a reduced vertical response compared to the fixed base condition at reactor support, and the 9% viscous damping to Kobe earthquake is required to get an equivalent vertical response with a fixed base condition
RSEIS and RFOC: Seismic Analysis in R
Lees, J. M.
2015-12-01
Open software is essential for reproducible scientific exchange. R-packages provide a platform for development of seismological investigation software that can be properly documented and traced for data processing. A suite of R packages designed for a wide range of seismic analysis is currently available in the free software platform called R. R is a software platform based on the S-language developed at Bell Labs decades ago. Routines in R can be run as standalone function calls, or developed in object-oriented mode. R comes with a base set of routines, and thousands of user developed packages. The packages developed at UNC include subroutines and interactive codes for processing seismic data, analyzing geographic information (GIS) and inverting data involved in a variety of geophysical applications. On CRAN (Comprehensive R Archive Network, http://www.r-project.org/) currently available packages related to seismic analysis are RSEIS, Rquake, GEOmap, RFOC, zoeppritz, RTOMO, and geophys, Rwave, PEIP, hht, rFDSN. These include signal processing, data management, mapping, earthquake location, deconvolution, focal mechanisms, wavelet transforms, Hilbert-Huang Transforms, tomographic inversion, and Mogi deformation among other useful functionality. All software in R packages is required to have detailed documentation, making the exchange and modification of existing software easy. In this presentation, I will focus on packages RSEIS and RFOC, showing examples from a variety of seismic analyses. The R approach has similarities to the popular (and expensive) MATLAB platform, although R is open source and free to down load.
Methods for seismic analysis of nuclear power plants
International Nuclear Information System (INIS)
Gantenbein, F.
1990-01-01
The seismic analysis of a complex structure, such as a nuclear power plant, is done in various steps. An overview of the methods, used in each of these steps will be given in the following chapters: Seismic analysis of the buildings taking into account structures with important mass or stiffness. The input to the building analysis, called ground motion, is described by an accelerogram or a response spectra. In this step, soil structure interaction has to be taken into account. Various methods are available: Impedance, finite element. The response of the structure can be calculated by spectral method or by time history analysis; advantages and limitations of each method will be shown. Calculation of floor response spectrum which are the data for the equipment analysis. Methods to calculate this spectrum will be described. Seismic analysis of the equipments. Presentation of the methods for both monosupported and multisupported equipment will be given. In addition methods to analyse equipments which present non-linearities associated to the boundary conditions such as impacts, sliding will be presented. (author). 30 refs, 15 figs
Seismic analysis of piping systems subjected to multiple support excitations
International Nuclear Information System (INIS)
Sundararajan, C.; Vaish, A.K.; Slagis, G.C.
1981-01-01
The paper presents the results of a comparative study between the multiple response spectrum method and the time-history method for the seismic analysis of nuclear piping systems subjected to different excitation at different supports or support groups. First, the necessary equations for the above analysis procedures are derived. Then, three actual nuclear piping systems subjected to single and multiple excitations are analyzed by the different methods, and extensive comparisons of the results (stresses) are made. Based on the results, it is concluded that the multiple response spectrum analysis gives acceptable results as compared to the ''exact'', but much more costly, time-history analysis. 6 refs
Review Article: Numerical analysis of the seismic behaviour of earth dam
Directory of Open Access Journals (Sweden)
Y. Parish
2009-03-01
Full Text Available The present study concerns analysis of the seismic response of earth dams. The behaviour of both the shell and core of the dam is described using the simple and popular non associated Mohr-Coulomb criterion. The use of this constitutive model is justified by the difficulty to obtain constitutive parameters for more advanced constitutive relations including isotropic and kinematic hardening. Analyses with real earthquake records show that the seismic loading induces plasticity in a large part of the shell and in the lower part of the core. Analysis shows that plasticity should be considered in the analysis of the seismic response of the dam, because it leads to a decrease in the natural frequencies of the dam together to energy dissipation, which could significantly affect the seismic response of the dam. Plastic analysis constitutes also a good tool for the verification of the stability of the dam under seismic loading.
International Nuclear Information System (INIS)
Cho, Eu-Kyeong; Park, Jung-Il; Lee, Jong-Rim
1995-01-01
A new analytic scheme to resolve the liquid-soil-structure interaction problem in cylindrical liquid storage tanks on the deformable soil is presented. Boundary elements and finite elements are combined to simulate the liquid-structure coupling effect while tuned foundation impedance functions (TFIF's) are representing the motion of the rigid foundation block on the flexible soil. Because the coupled dynamic system is expressed explicitly in terms of mass and stiffness, the developed scheme is applicable to any standard dynamic analysis methodologies. (author)
Seismic response Analyses of Hanaro in-chimney bracket structures
International Nuclear Information System (INIS)
Lee, Jae Han; Ryu, J.S.; Cho, Y.G.; Lee, H.Y.; Kim, J.B.
1999-05-01
The in-chimney bracket will be installed in the upper part of chimney, which holds the capsule extension pipes in upper one-third of length. For evaluating the effects on the capsules and related reactor structures, ANSYS finite element analysis model is developed and the dynamic characteristics are analyzed. The seismic response anlayses of in-chimney bracket and related reactor structures of HANARO under the design earthquake response spectrum loads of OBE (0.1 g) and SSE (0.2 g) are performed. The maximum horizontal displacements of the flow tubes are within the minimum half gaps between close flow tubes, it is expected that these displacement will not produce any contact between neighbor flow tubes. The stress values in main points of reactor structures and in-chimney bracket for the seismic loads are also within the ASME Code limits. It is also confirmed that the fatigue usage factor is much less than 1.0. So, any damage on structural integrity is not expected when an in-chimney bracket is installed to upper part of the reactor chimney. (author). 12 refs., 24 tabs., 37 figs
Khachay, OA; Khachay, OYu
2018-03-01
It is shown that the dynamic process of mining can be controlled using the catastrophe theory. The control parameters can be values of blasting energy and locations of explosions relative to an area under study or operation. The kinematic and dynamic parameters of the deformation waves, as well as the structural features of rock mass through which these waves pass act as internal parameters. The use of the analysis methods for short-term and medium-term forecast of rock mass condition with the control parameters only is insufficient in the presence of sharp heterogeneity. However, the joint use of qualitative recommendations of the catastrophe theory and spatial–temporal data of changes in the internal parameters of rock mass will allow accident prevention in the course of mining.
Seismic response and damping tests of small bore LMFBR piping and supports
International Nuclear Information System (INIS)
Barta, D.A.; Anderson, M.J.; Severud, L.K.; Lindquist, M.R.
1984-01-01
Seismic testing and analysis of a prototypical Liquid Metal Fast Breeder Reactor (LMFBR) small bore piping system is described. Measured responses to simulated seismic excitations are compared with analytical predictions based on NRC Regulatory Guide 1.61 and measured system damping values. The test specimen was representative of a typical LMFBR insulated small bore piping system, and it was supported from a rigid test frame by prototypic dead weight supports, mechanical snubbers and pipe clamps
Recent Vs. Historical Seismicity Analysis For Banat Seismic Region (Western Part Of Romania
Directory of Open Access Journals (Sweden)
Oros Eugen
2015-03-01
Full Text Available The present day seismic activity from a region reflects the active tectonics and can confirm the seismic potential of the seismogenic sources as they are modelled using the historical seismicity. This paper makes a comparative analysis of the last decade seismicity recorded in the Banat Seismic Region (western part of Romania and the historical seismicity of the region (Mw≥4.0. Four significant earthquake sequences have been recently localized in the region, three of them nearby the city of Timisoara (January 2012 and March 2013 and the fourth within Hateg Basin, South Carpathians (October 2013. These sequences occurred within the epicentral areas of some strong historical earthquakes (Mw≥5.0. The main events had some macroseismic effects on people up to some few kilometers from the epicenters. Our results update the Romanian earthquakes catalogue and bring new information along the local seismic hazard sources models and seismotectonics.
International Nuclear Information System (INIS)
Bazzurro, P.; Manfredini, G.M.; Diaz Molina, I.
1995-01-01
The Seismic Damage Hazard Analysis (SDHA) is a methodology which couples conventional Seismic Hazard Analysis (SHA) and non-linear response analysis to seismic loadings. This is a powerful tool in the retrofit process: SDHA permits the direct computation of the probability of occurrence of damage and, eventually, collapse of existing and upgraded structural systems. The SDHA methodology is a significant step towards a better understanding and quantification of structural seismic risk. SDHA incorporates and explicitly accounts for seismic load variability, seismic damage potential variability and structural resistance uncertainty. In addition, SDHA makes available a sound strategy to perform non-linear dynamic analyses. A limited number of non-linear dynamic analyses is sufficient to obtain estimates of damage and its probability of occurrence. The basic concepts of the SDHA methodology are briefly reviewed. Illustrative examples are presented, regarding a power house structure, a tubular structure and seabed slope stability problem. (author)
One-dimensional Seismic Analysis of a Solid-Waste Landfill
International Nuclear Information System (INIS)
Castelli, Francesco; Lentini, Valentina; Maugeri, Michele
2008-01-01
Analysis of the seismic performance of solid waste landfill follows generally the same procedures for the design of embankment dams, even if the methods and safety requirements should be different. The characterization of waste properties for seismic design is difficult due the heterogeneity of the material, requiring the procurement of large samples. The dynamic characteristics of solid waste materials play an important role on the seismic response of landfill, and it also is important to assess the dynamic shear strengths of liner materials due the effect of inertial forces in the refuse mass. In the paper the numerical results of a dynamic analysis are reported and analysed to determine the reliability of the common practice of using 1D analysis to evaluate the seismic response of a municipal solid-waste landfill. Numerical results indicate that the seismic response of a landfill can vary significantly due to reasonable variations of waste properties, fill heights, site conditions, and design rock motions
Study of seismic responses of Candu-3 reactor building using isolator bearings
International Nuclear Information System (INIS)
Biswas, J.K.
1992-01-01
Seismic isolator bearings are known to increase reliability, reduce cost and increase the potential sitings for nuclear power plants located in regions of high seismicity. High seismic activities in Canada occur mainly in the western coast, the Grand Banks and regions of Quebec along the St. Lawrence river. In Canada, nuclear power plants are located in Ontario, Quebec and New Brunswick where the seismicity levels are low to moderate. Consequently, seismic isolator bearings have not been used in the existing nuclear power plants in Canada. The present paper examines the effect of using seismic isolator bearings in the design for the new CANDU3 which would be suitable for regions having high seismicity. The CANDU3 Nuclear Power Plant is rated at 450 MW of net output power and is a smaller version of its predecessor CANDU6 successfully operating in Canada and abroad. The design of CANDU3 is being developed by AECL CANDU. Advanced technologies for design, construction and plant operation have been utilized. During the conceptual development of the CANDU3 design, various design options including the use of isolator bearings were considered. The present paper presents an overview of seismic isolation technology and summarizes the analytical work for predicting the seismic behavior of the CANDU3 reactor building. A lumped-parameter dynamic model for the reactor building is used for the analysis. The characteristics of the bearings are utilized in the analysis work. The time-history modal analysis has been used to compute the seismic responses. Seismic responses of the reactor building with and without isolator bearings are compared. The isolator bearings are found to reduce the accelerations of the reactor building. As a result, a lower level of seismic qualification for components and systems would be required. The use of these bearings however increases rigid body seismic displacements of the structure requiring special considerations in the layout and interfaces for
Seismic analysis of nonstructural elements
Toledo Arias, Carlos Alberto
2013-01-01
Nonstructural failures have accounted for the majority of earthquake damage in several recent earthquakes. Thus, it is critical to raise awareness of potential nonstructural risks, the costly consequences of nonstructural failures, and the opportunities that exist to limit future losses. Non-structural parts of a building have the potential to modify earthquake response of the primary structure in an unplanned way. This can lead to severe structural damage or even collapse. Failure of non-str...
Seismic hazard analysis of Sinop province, Turkey using ...
Indian Academy of Sciences (India)
1997-01-11
Jan 11, 1997 ... 2008 in the Sinop province of Turkey this study presents a seismic hazard analysis based on ... Considering the development and improvement ... It is one of the most populated cities in the coun- ... done as reliably as the seismic hazard of region per- .... Seismic safety work of underground networks was.
Theoretical seismic analysis of butterfly valve for nuclear power plant
International Nuclear Information System (INIS)
Han, Sang Uk; Ahn, Jun Tae; Han, Seung Ho; Lee, Kyung Chul
2012-01-01
Valves are one of the most important components of a pipeline system in a nuclear power plant, and it is important to ensure their structural safety under seismic loads. A crucial aspect of structural safety verification is the seismic qualification, and therefore, an optimal shape design and experimental seismic qualification is necessary in case the configuration of the valve parts needs to be modified and their performance needs to be improved. Recently, intensive numerical analyses have been preformed before the experimental verification in order to determine the appropriate design variables that satisfy the performance requirements under seismic loads. In this study, static and dynamic numerical structural analyses of a 200A butterfly valve for a nuclear power plant were performed according to the KEPIC MFA. The result of static analysis considering an equivalent static load under SSE condition gave an applied stress of 135MPa. In addition, the result of dynamic analysis gave an applied stress of 183MPa, where the CQC method using response spectrums was taken into account. These values are under the allowable strength of the materials used for manufacturing the butterfly valve, and therefore, its structural safety satisfies the requirements of KEPIC MFA
Theoretical seismic analysis of butterfly valve for nuclear power plant
Energy Technology Data Exchange (ETDEWEB)
Han, Sang Uk; Ahn, Jun Tae; Han, Seung Ho [Donga Univ., Busan (Korea, Republic of); Lee, Kyung Chul [Dukwon Valve Co., Ltd., Busan (Korea, Republic of)
2012-09-15
Valves are one of the most important components of a pipeline system in a nuclear power plant, and it is important to ensure their structural safety under seismic loads. A crucial aspect of structural safety verification is the seismic qualification, and therefore, an optimal shape design and experimental seismic qualification is necessary in case the configuration of the valve parts needs to be modified and their performance needs to be improved. Recently, intensive numerical analyses have been preformed before the experimental verification in order to determine the appropriate design variables that satisfy the performance requirements under seismic loads. In this study, static and dynamic numerical structural analyses of a 200A butterfly valve for a nuclear power plant were performed according to the KEPIC MFA. The result of static analysis considering an equivalent static load under SSE condition gave an applied stress of 135MPa. In addition, the result of dynamic analysis gave an applied stress of 183MPa, where the CQC method using response spectrums was taken into account. These values are under the allowable strength of the materials used for manufacturing the butterfly valve, and therefore, its structural safety satisfies the requirements of KEPIC MFA.
Analysis of seismic waves and strong ground motion
International Nuclear Information System (INIS)
Simpson, I.C.; Sutton, R.
1976-10-01
A number of Western USA earthquake acceleration-time histories concerning events of magnitude less than 6 are considered and their Fourier spectra calculated. An analysis of some of the simpler types of seismic wave is given in order to consider the generation of a spatially dependent acceleration-time history suitable for input into a soil-structure program of analysis. Such an acceleration-time history is required by a comprehensive analysis of soil-structure interaction since the conventionally assumed model of vertically propagating seismic waves, which give rise to three spatially independent ground motions, can lead to over-conservative estimates of the building response in the high frequency range. The possible application is discussed of a given component of a recorded acceleration-time history to the base of structure under the assumption of surface Rayleigh waves or obliquely incident P and SV bulk waves. (author)
Veeraian, Parthasarathi; Gandhi, Uma; Mangalanathan, Umapathy
2018-04-01
Seismic transducers are widely used for measurement of displacement, velocity, and acceleration. This paper presents the design of seismic transducer in the fractional domain for the measurement of displacement and acceleration. The fractional order transfer function for seismic displacement and acceleration transducer are derived using Grünwald-Letnikov derivative. Frequency response analysis of fractional order seismic displacement transducer (FOSDT) and fractional order seismic acceleration transducer (FOSAT) are carried out for different damping ratio with the different fractional order, and the maximum dynamic measurement range is identified. The results demonstrate that fractional order seismic transducer has increased dynamic measurement range and less phase distortion as compared to the conventional seismic transducer even with a lower damping ratio. Time response of FOSDT and FOSAT are derived analytically in terms of Mittag-Leffler function, the effect of fractional behavior in the time domain is evaluated from the impulse and step response. The fractional order system is found to have significantly reduced overshoot as compared to the conventional transducer. The fractional order seismic transducer design proposed in this paper is illustrated with a design example for FOSDT and FOSAT. Finally, an electrical equivalent of FOSDT and FOSAT is considered, and its frequency response is found to be in close agreement with the proposed fractional order seismic transducer.
Huerta, F. V.; Granados, I.; Aguirre, J.; Carrera, R. Á.
2017-12-01
Nowadays, in hydrocarbon industry, there is a need to optimize and reduce exploration costs in the different types of reservoirs, motivating the community specialized in the search and development of alternative exploration geophysical methods. This study show the reflection response obtained from a shale gas / oil deposit through the method of seismic interferometry of ambient vibrations in combination with Wavelet analysis and conventional seismic reflection techniques (CMP & NMO). The method is to generate seismic responses from virtual sources through the process of cross-correlation of records of Ambient Seismic Vibrations (ASV), collected in different receivers. The seismic response obtained is interpreted as the response that would be measured in one of the receivers considering a virtual source in the other. The acquisition of ASV records was performed in northern of Mexico through semi-rectangular arrays of multi-component geophones with instrumental response of 10 Hz. The in-line distance between geophones was 40 m while in cross-line was 280 m, the sampling used during the data collection was 2 ms and the total duration of the records was 6 hours. The results show the reflection response of two lines in the in-line direction and two in the cross-line direction for which the continuity of coherent events have been identified and interpreted as reflectors. There is certainty that the events identified correspond to reflections because the time-frequency analysis performed with the Wavelet Transform has allowed to identify the frequency band in which there are body waves. On the other hand, the CMP and NMO techniques have allowed to emphasize and correct the reflection response obtained during the correlation processes in the frequency band of interest. The results of the processing and analysis of ASV records through the seismic interferometry method have allowed us to see interesting results in light of the cross-correlation process in combination with
Impact of mesh and DEM resolutions in SEM simulation of 3D seismic response
Khan, Saad; van der Meijde, M.; van der Werff, H.M.A.; Shafique, Muhammad
2017-01-01
This study shows that the resolution of a digital elevation model (DEM) and model mesh strongly influences 3D simulations of seismic response. Topographic heterogeneity scatters seismic waves and causes variation in seismic response (am-plification and deamplification of seismic amplitudes) at the
Fast principal component analysis for stacking seismic data
Wu, Juan; Bai, Min
2018-04-01
Stacking seismic data plays an indispensable role in many steps of the seismic data processing and imaging workflow. Optimal stacking of seismic data can help mitigate seismic noise and enhance the principal components to a great extent. Traditional average-based seismic stacking methods cannot obtain optimal performance when the ambient noise is extremely strong. We propose a principal component analysis (PCA) algorithm for stacking seismic data without being sensitive to noise level. Considering the computational bottleneck of the classic PCA algorithm in processing massive seismic data, we propose an efficient PCA algorithm to make the proposed method readily applicable for industrial applications. Two numerically designed examples and one real seismic data are used to demonstrate the performance of the presented method.
Seismic response of free standing fuel rack construction to 3-D floor motion
International Nuclear Information System (INIS)
Soler, A.I.; Singh, K.
1983-01-01
Seismic analysis of free standing submerged racks is complicated by the presence of water and structural non-linearities such as fuel assembly cell impact and floor interface friction. A direct time integration technique has been proposed to analyze this class of structures. Application of the time integration technique on a fourteen degree of freedom lumped mass model of the rack reveals some heretofore unpublished quirks in the structure's behavior. The method of analysis is utilized to compare the seismic response of some representative rack designs. Results show wide differences in the structural response, depending on the fabrication details of racks
Seismic analysis of the Aguirre Nuclear Reactor
International Nuclear Information System (INIS)
Sepulveda Soza, Cristian
1999-01-01
This thesis aims to verify the seismic design of the Aguirre Nuclear Reactor using the finite elements method and comparing the results with the original analysis. The study focused on the dynamic interaction of soil and structures, using the ANSYS program for the analysis, which was implemented for a work station under a UNIX platform belonging to the Chilean Nuclear Energy Commission. The modeling of the structures was carried out following International Atomic Energy recommendations, those of the makers of the Swanson Analysis Systems program and the prior study by S y S Ingenieros Consultores. Two-dimensional models were developed with axial and symmetry and three-dimensional models with symmetric and asymmetric plans, where the retaining building, the pond block and the soil down to the basal rock were included. The seismic stresses were defined according to the Chilean Standard NCh433.of96, using the spectrum of design accelerations for type II soils for the structural models and type IV for the soil-structure interaction models.The results of interest for this study are: the compression and cutting tensions, the unitary cut distortions and the displacements, which are shown graphically and are compared between the different models and with the original analysis. A sensitivity analysis was prepared for the models with axial symmetry considering soil reaction coefficient values of 20, 10, 5, 2, 1 and 0.5 kp/cm 3 ; and four screens with maximum sizes of 100, 50, 25 and 12.5 cm. The behavior of the stressed materials was studied as well as the result of the seismic stress (CS)
Seismic hazards: New trends in analysis using geologic data
International Nuclear Information System (INIS)
Schwartz, D.P.; Coppersmith, K.J.
1986-01-01
In the late 1960s and early 1970s, largely in response to expansion of nuclear power plant siting and issuance of a code of federal regullations by the Nuclear Regulatory Commission referred to as Appendix A-10CFR100, the need to characterize the earthquake potential of individual faults for seismic design took on greater importance. Appendix A established deterministic procedures for assessing the seismic hazard at nuclear power plant sites. Bonilla and Buchanan, using data from historical suface-faulting earthquakes, developed a set of statistical correlations relating earthquake magnitude to surface rupture length and to surface displacement. These relationships have been refined and updated along with the relationship between fault area and magnitude and seismic moment and moment magnitude have served as the basis for selecting maximum earthquakes in a wide variety of design situations. In the paper presented, the authors discuss new trends in seismic hazard analysis using geologic data, with special emphasis on fault-zone segmentation and recurrence models and the way in which they provide a basis for evaluating long-term earthquake potential
Seismic analysis of the MFTF facility
International Nuclear Information System (INIS)
Maslenikov, O.R.; Johnson, J.J.; Tiong, L.W.; Mraz, M.J.
1985-01-01
Seismic analyses were performed on the Mirror Fusion Test Facility (MFTF-B) located at the Lawrence Livermore National Laboratory, Livermore, CA. The three major structures studied were the vacuum vessel, the concrete shielding vault, and the steel frame enclosure building. The analyses performed on these structures ranged from fixed-base response spectrum analyses to soil-structure interaction analyses including the effects of structure-to-structure interaction and foundation flexibility. The results of these studies showed that the presence of the vault significantly affects the response of the vessel; that modeling the flexibility of the vault footing is important when studying forces near the base of the wall; and that the vault had very little effect on the building response. (orig.)
Seismic response analyses for reactor facilities at Savannah River
International Nuclear Information System (INIS)
Miller, C.A.; Costantino, C.J.; Xu, J.
1991-01-01
The reactor facilities at the Savannah River Plant (SRP) were designed during the 1950's. The original seismic criteria defining the input ground motion was 0.1 G with UBC [uniform building code] provisions used to evaluate structural seismic loads. Later ground motion criteria have defined the free field seismic motion with a 0.2 G ZPA [free field acceleration] and various spectral shapes. The spectral shapes have included the Housner spectra, a site specific spectra, and the US NRC [Nuclear Regulatory Commission] Reg. Guide 1.60 shape. The development of these free field seismic criteria are discussed in the paper. The more recent seismic analyses have been of the following type: fixed base response spectra, frequency independent lumped parameter soil/structure interaction (SSI), frequency dependent lumped parameter SSI, and current state of the art analyses using computer codes such as SASSI. The results from these computations consist of structural loads and floor response spectra (used for piping and equipment qualification). These results are compared in the paper and the methods used to validate the results are discussed. 14 refs., 11 figs
Seismic response of rock joints and jointed rock mass
International Nuclear Information System (INIS)
Ghosh, A.; Hsiung, S.M.; Chowdhury, A.H.
1996-06-01
Long-term stability of emplacement drifts and potential near-field fluid flow resulting from coupled effects are among the concerns for safe disposal of high-level nuclear waste (HLW). A number of factors can induce drift instability or change the near-field flow patterns. Repetitive seismic loads from earthquakes and thermal loads generated by the decay of emplaced waste are two significant factors. One of two key technical uncertainties (KTU) that can potentially pose a high risk of noncompliance with the performance objectives of 10 CFR Part 60 is the prediction of thermal-mechanical (including repetitive seismic load) effects on stability of emplacement drifts and the engineered barrier system. The second KTU of concern is the prediction of thermal-mechanical-hydrological (including repetitive seismic load) effects on the host rock surrounding the engineered barrier system. The Rock Mechanics research project being conducted at the Center for Nuclear Waste Regulatory Analyses (CNWRA) is intended to address certain specific technical issues associated with these two KTUs. This research project has two major components: (i) seismic response of rock joints and a jointed rock mass and (ii) coupled thermal-mechanical-hydrological (TMH) response of a jointed rock mass surrounding the engineered barrier system (EBS). This final report summarizes the research activities concerned with the repetitive seismic load aspect of both these KTUs
Soil-structure interaction analysis of large scale seismic test model at Hualien in Taiwan
International Nuclear Information System (INIS)
Jang, J. B.; Ser, Y. P.; Lee, J. L.
2001-01-01
The issue of SSI in seismic analysis and design of NPPs is getting important, as it may be inevitable to build NPPs at sites with soft foundation due to ever-increasing difficulty in acquiring new construction sites for NPPs. And, the improvement of seismic analysis technique including soil-structure interaction analysis essential to achieve reasonable seismic design for structures and equipments, etc. of NPPs. Therefore, among the existing SSI analysis programs, the most prevalent SASSI is verified through the comparison numerical analysis results with recorded response results of Hualien project in this study. As a result, SASSI accurately estimated the recorded response results for the fundamental frequency and peak acceleration of structure and was proved to be reliable and useful for the seismic analysis and design of NPPs
Seismic analysis of steam generator and parameter sensitivity studies
International Nuclear Information System (INIS)
Qian Hao; Xu Dinggen; Yang Ren'an; Liang Xingyun
2013-01-01
Background: The steam generator (SG) serves as the primary means for removing the heat generated within the reactor core and is part of the reactor coolant system (RCS) pressure boundary. Purpose: Seismic analysis in required for SG, whose seismic category is Cat. I. Methods: The analysis model of SG is created with moisture separator assembly and tube bundle assembly herein. The seismic analysis is performed with RCS pipe and Reactor Pressure Vessel (RPV). Results: The seismic stress results of SG are obtained. In addition, parameter sensitivities of seismic analysis results are studied, such as the effect of another SG, support, anti-vibration bars (AVBs), and so on. Our results show that seismic results are sensitive to support and AVBs setting. Conclusions: The guidance and comments on these parameters are summarized for equipment design and analysis, which should be focused on in future new type NPP SG's research and design. (authors)
Seismic analysis of the APR1400 nuclear reactor system using a verified beam element model
International Nuclear Information System (INIS)
Park, Jong-beom; Park, No-Cheol; Lee, Sang-Jeong; Park, Young-Pil; Choi, Youngin
2017-01-01
Highlights: • A simplified beam element model is constructed based on the real dynamic characteristics of the APR1400. • Time history analysis is performed to calculate the seismic responses of the structures. • Large deformations can be observed at the in-phase mode of reactor vessel and core support barrel. - Abstract: Structural integrity is the first priority in the design of nuclear reactor internal structures. In particular, nuclear reactor internals should be designed to endure external forces, such as those due to earthquakes. Many researchers have performed finite element analyses to meet these design requirements. Generally, a seismic analysis model should reflect the dynamic characteristics of the target system. However, seismic analysis based on the finite element method requires long computation times as well as huge storage space. In this research, a beam element model was developed and confirmed based on the real dynamic characteristics of an advanced pressurized water nuclear reactor 1400 (APR1400) system. That verification process enhances the accuracy of the finite element analysis using the beam elements, remarkably. Also, the beam element model reduces seismic analysis costs. Therefore, the beam element model was used to perform the seismic analysis. Then, the safety of the APR1400 was assessed based on a seismic analysis of the time history responses of its structures. Thus, efficient, accurate seismic analysis was demonstrated using the proposed beam element model.
Seismic analysis of the APR1400 nuclear reactor system using a verified beam element model
Energy Technology Data Exchange (ETDEWEB)
Park, Jong-beom [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Park, No-Cheol, E-mail: pnch@yonsei.ac.kr [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Lee, Sang-Jeong; Park, Young-Pil [Department of Mechanical Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722 (Korea, Republic of); Choi, Youngin [Korea Institute of Nuclear Safety, 62 Gwahak-ro, Yuseong-gu, Daejeon 34142 (Korea, Republic of)
2017-03-15
Highlights: • A simplified beam element model is constructed based on the real dynamic characteristics of the APR1400. • Time history analysis is performed to calculate the seismic responses of the structures. • Large deformations can be observed at the in-phase mode of reactor vessel and core support barrel. - Abstract: Structural integrity is the first priority in the design of nuclear reactor internal structures. In particular, nuclear reactor internals should be designed to endure external forces, such as those due to earthquakes. Many researchers have performed finite element analyses to meet these design requirements. Generally, a seismic analysis model should reflect the dynamic characteristics of the target system. However, seismic analysis based on the finite element method requires long computation times as well as huge storage space. In this research, a beam element model was developed and confirmed based on the real dynamic characteristics of an advanced pressurized water nuclear reactor 1400 (APR1400) system. That verification process enhances the accuracy of the finite element analysis using the beam elements, remarkably. Also, the beam element model reduces seismic analysis costs. Therefore, the beam element model was used to perform the seismic analysis. Then, the safety of the APR1400 was assessed based on a seismic analysis of the time history responses of its structures. Thus, efficient, accurate seismic analysis was demonstrated using the proposed beam element model.
Seismic response of reactor building on alluvial soil by direct implicit integration
International Nuclear Information System (INIS)
Thakkar, S.K.; Dinkar, A.K.
1983-01-01
The evaluation of seismic response of a reactor building is a complex problem. A study has been made in this paper of seismic response of a reactor building by direct implicit integration method. The direct implicit integration methods besides being unconditionally stable have the merit of including response of higher modes without much effort. A reactor building consisting of external shell, internal shell, internals and raft is considered to be resting on alluvium. The complete building including the foundation is idealized by axisymmetric finite elements. The structure is analyzed separately for horizontal and vertical components of ground motion using harmonic analysis. Total response is found by superposition of two responses. The variation of several parameters, such as soil stiffness, embedment depth, inertia of foundation, viscous boundary and damping on seismic response is studied. The structural response is seen to depend significantly on the soil stiffness and damping. The seismic response is observed to be less sensitive to embedment depth and inertia of foundation. The vertical accelerations on the raft, boiler room floor slab and dome due to vertical ground motions are quite appreciable. The viscous boundary is seen to alter structural response in significantly compared to rigid boundaries in a larger mesh and its use appears to be promising in absorbing energy of body waves when used with direct implicit integration method. (orig.)
Seismicity and source spectra analysis in Salton Sea Geothermal Field
Cheng, Y.; Chen, X.
2016-12-01
The surge of "man-made" earthquakes in recent years has led to considerable concerns about the associated hazards. Improved monitoring of small earthquakes would significantly help understand such phenomena and the underlying physical mechanisms. In the Salton Sea Geothermal field in southern California, open access of a local borehole network provides a unique opportunity to better understand the seismicity characteristics, the related earthquake hazards, and the relationship with the geothermal system, tectonic faulting and other physical conditions. We obtain high-resolution earthquake locations in the Salton Sea Geothermal Field, analyze characteristics of spatiotemporal isolated earthquake clusters, magnitude-frequency distributions and spatial variation of stress drops. The analysis reveals spatial coherent distributions of different types of clustering, b-value distributions, and stress drop distribution. The mixture type clusters (short-duration rapid bursts with high aftershock productivity) are predominately located within active geothermal field that correlate with high b-value, low stress drop microearthquake clouds, while regular aftershock sequences and swarms are distributed throughout the study area. The differences between earthquakes inside and outside of geothermal operation field suggest a possible way to distinguish directly induced seismicity due to energy operation versus typical seismic slip driven sequences. The spatial coherent b-value distribution enables in-situ estimation of probabilities for M≥3 earthquakes, and shows that the high large-magnitude-event (LME) probability zones with high stress drop are likely associated with tectonic faulting. The high stress drop in shallow (1-3 km) depth indicates the existence of active faults, while low stress drops near injection wells likely corresponds to the seismic response to fluid injection. I interpret the spatial variation of seismicity and source characteristics as the result of fluid
Analysis of seismic effects on reinforced concrete structures
International Nuclear Information System (INIS)
Tai, A.A.
1981-12-01
An important bibliographical research was undertaken in order to make the best possible analysis of the dynamic behaviour of materials and of structural components. This research work was completed by the study of the structures tested on a seismic table. The results obtained from this preliminary study, particularly those concerning the modification in the rigidity of reinforced concrete structures under alternate and seismic loading, enabled a calculation method (called ''equivalent static'') to be drawn up for analyzing the behaviour of reinforced concrete structures in earthquakes. This method takes into account the non-linearity of the behaviour of materials, in particular. The earthquake responses that were obtained by this method on gantries tested on a vibrating table, tally very satisfactorily with the test figures [fr
Seismic response of a nonsymmetric nuclear reactor building with a flexible stepped foundation
International Nuclear Information System (INIS)
Okano, H.; Sakai, A.; Takita, H.; Fukunishi, S.; Nakatogawa, T.; Kabayama, K.
1993-01-01
The effect of the non symmetry of a nuclear reactor building on its seismic response was studied. The nonsymmetric natures we considered, Included the eccentricity of the superstructure and the non symmetry of the cross section of the foundation. A three-dimensional analysis which employed Green's function was applied to study the interaction between the soil and the non symmetrically sectioned foundation. The effect of a flexible foundation on its seismic response was also studied by applying the sub structuring method, which combines the finite element method and Green's function method. (author)
International Nuclear Information System (INIS)
Takanashi, Koichi; Ohi, Kenichi
1988-01-01
A group of steel and reinforced concrete scaled structures with intentionally reduced seismic strength to 1/3 to 1/2 were constructed in 1983 for long term observation in order to collect precise data of earthquake response and grasp failure mechanisms during earthquakes. A monitoring system was installed in the structures as well as in the surrounding soil. Some reliable data have been successfully recorded since then, which can be available for verification of analytical models. (author)
Seismic analysis of liquid metal reactor piping systems
International Nuclear Information System (INIS)
Wang, C.Y.
1987-01-01
To safely assess the adequacy of the LMR piping, a three-dimensional piping code, SHAPS, has been developed at Argonne National Laboratory. This code was initially intended for calculating hydrodynamic-wave propagation in a complex piping network. It has salient features for treating fluid transients of fluid-structure interactions for piping with in-line components. The code also provides excellent structural capabilities of computing stresses arising from internal pressurization and 3-D flexural motion of the piping system. As part of the development effort, the SHAPS code has been further augmented recently by introducing the capabilities of calculating piping response subjected to seismic excitations. This paper describes the finite-element numerical algorithm and its applications to LMR piping under seismic excitations. A time-history analysis technique using the implicit temporal integration scheme is addressed. A 3-D pipe element is formulated which has eight degrees of freedom per node (three displacements, three rotations, one membrane displacement, and one bending rotation) to account for the hoop, flexural, rotational, and torsional modes of the piping system. Both geometric and material nonlinearities are considered. This algorithm is unconditionally stable and is particularly suited for the seismic analysis
Hata, Yoshiya; Ichii, Koji; Yamada, Masayuki; Tokida, Ken-Ichi; Takezawa, Koichiro; Shibao, Susumu; Mitsushita, Junji; Murata, Akira; Furukawa, Aiko; Koizumi, Keigo
Accurate evaluation on the seismic response characteristics of a road embankment is very important for the rational seismic assessment. However, in a lot of previous studies, the seismic response characteristics of an embankment were evaluated based on the results of shaking table test, centrifuge model test and dynamic FEM analysis. In this study, the transfer function and the shear wave velocity of a road embankment were evaluated based on the in-situ records of moderate earthquake observation and microtremor measurement. Test results show the possibility that the shear wave velocity of an embankment can be estimated by the earthquake observation or the microtremor measurement and the dynamic linear FEM analysis.
Seismic interferometry : Reconstructing the earth's reflection response
Draganov, D.S.; Wapenaar, C.P.A.; Thorbecke, J.W.
2006-01-01
In 1968, Jon Claerbout showed that the reflection response of a 1D acoustic medium can be reconstructed by autocorrelating the transmission response. Since then, several authors have derived relationships for reconstructing Green's functions at the surface, using crosscorrelations of (noise)
Structural reliability analysis and seismic risk assessment
International Nuclear Information System (INIS)
Hwang, H.; Reich, M.; Shinozuka, M.
1984-01-01
This paper presents a reliability analysis method for safety evaluation of nuclear structures. By utilizing this method, it is possible to estimate the limit state probability in the lifetime of structures and to generate analytically the fragility curves for PRA studies. The earthquake ground acceleration, in this approach, is represented by a segment of stationary Gaussian process with a zero mean and a Kanai-Tajimi Spectrum. All possible seismic hazard at a site represented by a hazard curve is also taken into consideration. Furthermore, the limit state of a structure is analytically defined and the corresponding limit state surface is then established. Finally, the fragility curve is generated and the limit state probability is evaluated. In this paper, using a realistic reinforced concrete containment as an example, results of the reliability analysis of the containment subjected to dead load, live load and ground earthquake acceleration are presented and a fragility curve for PRA studies is also constructed
ASSESSMENT OF SEISMIC ANALYSIS METHODOLOGIES FOR DEEPLY EMBEDDED NPP STRUCTURES
International Nuclear Information System (INIS)
XU, J.; MILLER, C.; COSTANTINO, C.; HOFMAYER, C.; GRAVES, H. NRC.
2005-01-01
Several of the new generation nuclear power plant designs have structural configurations which are proposed to be deeply embedded. Since current seismic analysis methodologies have been applied to shallow embedded structures (e.g., ASCE 4 suggest that simple formulations may be used to model embedment effect when the depth of embedment is less than 30% of its foundation radius), the US Nuclear Regulatory Commission is sponsoring a program at the Brookhaven National Laboratory with the objective of investigating the extent to which procedures acceptable for shallow embedment depths are adequate for larger embedment depths. This paper presents the results of a study comparing the response spectra obtained from two of the more popular analysis methods for structural configurations varying from shallow embedment to complete embedment. A typical safety related structure embedded in a soil profile representative of a typical nuclear power plant site was utilized in the study and the depths of burial (DOB) considered range from 25-100% the height of the structure. Included in the paper are: (1) the description of a simplified analysis and a detailed approach for the SSI analyses of a structure with various DOB, (2) the comparison of the analysis results for the different DOBs between the two methods, and (3) the performance assessment of the analysis methodologies for SSI analyses of deeply embedded structures. The resulting assessment from this study has indicated that simplified methods may be capable of capturing the seismic response for much deeper embedded structures than would be normally allowed by the standard practice
Seismic analysis for the supporting member of the Westinghouse AP1000 steam generator
International Nuclear Information System (INIS)
Xu Yu; Huang Mei; Tian Li; Hou Zhousen
2012-01-01
In this paper, the seismic performance analysis for the Supporting member of is carried out under the combined loads, including dead weight, earthquake loads, by using response spectrum analysis method in ANSYS. The stress qualification is also carried out based on ASME-Ⅲ-NF code. The results show that the stress of the Supporting member meets the seismic requirements for equipment, and the deformation of structure is within the allowable limits. (authors)
Approach for seismic risk analysis for CANDU plants in Korea
Energy Technology Data Exchange (ETDEWEB)
Lee, B-S; Kim, T; Kang, S-K [Korea Power Engineering Co., Seoul (Korea, Republic of); Hong, S-Y; Roh, S-R [Korea Electric Power Corp., Taejon (Korea, Republic of). Research Centre
1996-12-31
A seismic risk analysis for CANDU type plants has never been performed. The study presented here suggested that the approach generally applied to LWR type plants could lead to unacceptable result, if directly applied to CANDU plants. This paper presents a modified approach for the seismic risk analysis of CANDU plants. (author). 5 refs., 2 tabs., 2 figs.
User's manual of SECOM2: a computer code for seismic system reliability analysis
International Nuclear Information System (INIS)
Uchiyama, Tomoaki; Oikawa, Tetsukuni; Kondo, Masaaki; Tamura, Kazuo
2002-03-01
This report is the user's manual of seismic system reliability analysis code SECOM2 (Seismic Core Melt Frequency Evaluation Code Ver.2) developed at the Japan Atomic Energy Research Institute for systems reliability analysis, which is one of the tasks of seismic probabilistic safety assessment (PSA) of nuclear power plants (NPPs). The SECOM2 code has many functions such as: Calculation of component failure probabilities based on the response factor method, Extraction of minimal cut sets (MCSs), Calculation of conditional system failure probabilities for given seismic motion levels at the site of an NPP, Calculation of accident sequence frequencies and the core damage frequency (CDF) with use of the seismic hazard curve, Importance analysis using various indicators, Uncertainty analysis, Calculation of the CDF taking into account the effect of the correlations of responses and capacities of components, and Efficient sensitivity analysis by changing parameters on responses and capacities of components. These analyses require the fault tree (FT) representing the occurrence condition of the system failures and core damage, information about response and capacity of components and seismic hazard curve for the NPP site as inputs. This report presents the models and methods applied in the SECOM2 code and how to use those functions. (author)
Effect of soil-foundation-structure interaction on the seismic response of wind turbines
Directory of Open Access Journals (Sweden)
Sam Austin
2017-09-01
Full Text Available Soil-foundation-structure interaction can affect the seismic response of wind turbines. This paper studies the effects of soil-foundation-structure interaction on the seismic response of 65 kW, 1 MW, and 2 MW horizontal-axis wind turbines with truncated cone steel towers. Four types of foundations with frequency-based design were analyzed, including spread foundation, mono pile, pile group with cap, and anchored spread foundation. Soil is modeled both implicitly (subgrade reaction modulus and explicitly. The finite element model developed using the ANSYS program was first validated using experimental data. Numerical models are then analyzed in both frequency and time domains using the Block Lanczos and generalized HHT-α formulations. Recommendations were given to simplify the soil-foundation-structure interaction analysis of wind turbines subjected to seismic loading.
Seismic Isolation Working Meeting Gap Analysis Report
Energy Technology Data Exchange (ETDEWEB)
Coleman, Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sabharwall, Piyush [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2014-09-01
The ultimate goal in nuclear facility and nuclear power plant operations is operating safety during normal operations and maintaining core cooling capabilities during off-normal events including external hazards. Understanding the impact external hazards, such as flooding and earthquakes, have on nuclear facilities and NPPs is critical to deciding how to manage these hazards to expectable levels of risk. From a seismic risk perspective the goal is to manage seismic risk. Seismic risk is determined by convolving the seismic hazard with seismic fragilities (capacity of systems, structures, and components (SSCs)). There are large uncertainties associated with evolving nature of the seismic hazard curves. Additionally there are requirements within DOE and potential requirements within NRC to reconsider updated seismic hazard curves every 10 years. Therefore opportunity exists for engineered solutions to manage this seismic uncertainty. One engineered solution is seismic isolation. Current seismic isolation (SI) designs (used in commercial industry) reduce horizontal earthquake loads and protect critical infrastructure from the potentially destructive effects of large earthquakes. The benefit of SI application in the nuclear industry is being recognized and SI systems have been proposed, in the American Society of Civil Engineers (ASCE) 4 standard, to be released in 2014, for Light Water Reactors (LWR) facilities using commercially available technology. However, there is a lack of industry application to the nuclear industry and uncertainty with implementing the procedures outlined in ASCE-4. Opportunity exists to determine barriers associated with implementation of current ASCE-4 standard language.
Development and seismic evaluation of the seismic monitoring analysis system for HANARO
International Nuclear Information System (INIS)
Ryu, J. S.; Youn, D. B.; Kim, H. G.; Woo, J. S.
2003-01-01
Since the start of operation, the seismic monitoring system has been utilized for monitoring an earthquake at the HANARO site. The existing seismic monitoring system consists of field sensors and monitoring panel. The analog-type monitoring system with magnetic tape recorder is out-of-date model. In addition, the disadvantage of the existing system is that it does not include signal-analyzing equipment. Therefore, we have improved the analog seismic monitoring system except the field sensors into a new digital Seismic Monitoring Analysis System(SMAS) that can monitor and analyze earthquake signals. To achieve this objective for HANARO, the digital type hardware of the SMAS has been developed. The seismic monitoring and analysis programs that can provide rapid and precise information for an earthquake were developed. After the installation of the SMAS, we carried out the Site Acceptance Test (SAT) to confirm the functional capability of the newly developed system. The results of the SAT satisfy the requirements of the fabrication technical specifications. In addition, the seismic characteristics and structural integrity of the SMAS were evaluated. The results show that the cabinet of SMAS can withstand the effects of seismic loads and remain functional. This new SMAS is operating in the HANARO instrument room to acquire and analyze the signal of an earthquake
Development of analysis methods for seismically isolated nuclear structures
International Nuclear Information System (INIS)
Yoo, Bong; Lee, Jae-Han; Koo, Gyeng-Hoi
2002-01-01
KAERI's contributions to the project entitled Development of Analysis Methods for Seismically Isolated Nuclear Structures under IAEA CRP of the intercomparison of analysis methods for predicting the behaviour of seismically isolated nuclear structures during 1996-1999 in effort to develop the numerical analysis methods and to compare the analysis results with the benchmark test results of seismic isolation bearings and isolated nuclear structures provided by participating countries are briefly described. Certain progress in the analysis procedures for isolation bearings and isolated nuclear structures has been made throughout the IAEA CRPs and the analysis methods developed can be improved for future nuclear facility applications. (author)
Seismic transient analysis of a containment vessel with penetrations
International Nuclear Information System (INIS)
Dahlke, H.J.; Weiner, E.O.
1979-12-01
A linear transient analysis of the FFTF containment vessel was conducted with STAGS to justify the load levels used for the seismic qualification testing of the heating and ventiliation valve operators. The modeling consists of a thin axisymmetric shell for the containment vessel with four penetrations characterized by linear and rotational inertias as well as attachment characteristics to the shell. Motions considered are horizontal, rocking and vertical input to the base, and the solution is carried out by direct integration. Results show that the test levels and the approximate analyses considered are conservative. Response spectra for some containment vessel penetrations applicable to the model are presented
Non linear structures seismic analysis by modal synthesis
International Nuclear Information System (INIS)
Aita, S.; Brochard, D.; Guilbaud, D.; Gibert, R.J.
1987-01-01
The structures submitted to a seismic excitation, may present a great amplitude response which induces a non linear behaviour. These non linearities have an important influence on the response of the structure. Even in this case (local shocks) the modal synthesis method remains attractive. In this paper we will present the way of taking into account, a local non linearity (shock between structures) in the seismic response of structures, by using the modal synthesis method [fr
Source modelling in seismic risk analysis for nuclear power plants
International Nuclear Information System (INIS)
Yucemen, M.S.
1978-12-01
The proposed probabilistic procedure provides a consistent method for the modelling, analysis and updating of uncertainties that are involved in the seismic risk analysis for nuclear power plants. The potential earthquake activity zones are idealized as point, line or area sources. For these seismic source types, expressions to evaluate their contribution to seismic risk are derived, considering all the possible site-source configurations. The seismic risk at a site is found to depend not only on the inherent randomness of the earthquake occurrences with respect to magnitude, time and space, but also on the uncertainties associated with the predicted values of the seismic and geometric parameters, as well as the uncertainty in the attenuation model. The uncertainty due to the attenuation equation is incorporated into the analysis through the use of random correction factors. The influence of the uncertainty resulting from the insufficient information on the seismic parameters and source geometry is introduced into the analysis by computing a mean risk curve averaged over the various alternative assumptions on the parameters and source geometry. Seismic risk analysis is carried for the city of Denizli, which is located in the seismically most active zone of Turkey. The second analysis is for Akkuyu
Seismic risk analysis for the fast breeder prototype SNR-300 in Kalkar (FRG)
International Nuclear Information System (INIS)
Hosser, D.
1983-01-01
This paper summarizes the seismic part of the SNR-300 Risk Oriented Analysis. Two different approaches were used for the seismic hazard description. In the first one, similar to the German Risk Study for PWR, the seismic input was given by a site-independent mean acceleration response spectrum and duration of strong motion prescribed for the design of the plant; the spectrum was scaled with the peak ground acceleration the probability of exceedance of which at the site Kalkar had been calculated in a former seismic hazard tudy. For the second approach, site- and intensity- dependent mean acceleration response spectra and duration of strong motion were derived and the probability of exceedance of the site intensity was evaluated in a probabilistic seismic hazard analysis. The seismic responses of safety related and other important buildings were calculated by time-history analyses using artificial acceleration time-histories with the given frequency content and duration of strong motion. The influence of uncertainties in dynamic soil parameters and structural modelling was assessed in parametric studies. Some important structural elements within the buildings were investigated in more detail. Their seismic performance was evaluated using ultimate limit state definitions according to the respective design codes or rotation limits for nonlinear dynamic calculations. (orig./RW)
Seismic fault analysis of Chicoutimi region
International Nuclear Information System (INIS)
Woussen, G.; Ngandee, S.
1996-01-01
On November 25, 1988, an earthquake measuring 6.5 on the Richter Scale occurred at a depth of 29 km in Precambrian bedrock in the Saguenay Region (Quebec). Given that the seismic event was located near a major zone of normal faults, it is important to determine if the earthquake could be associated with this large structure or with faults associated with this structure. This is discussed through a compilation and interpretation of structural discontinuities on key outcrops in the vicinity of the epicenter. The report is broken in four parts. The first part gives a brief overview of the geology in order to provide a geologic context for the structural measurements. The second comprises an analysis of fractures in each of the three lithotectonic units defined in the first part. The third part discusses the data and the fourth provides a conclusion. 30 refs., 53 figs
Data analysis for seismic motion characteristics
International Nuclear Information System (INIS)
Ishimaru, Tsuneari; Kohriya, Yorihide
2002-10-01
This data analysis is aimed at studying the characteristics of amplification of acceleration amplitude from deep underground to the surface, and is one of several continuous studies on the effects of earthquake motion. Seismic wave records were observed via a center array located in Shibata-cho, Miyagi Prefecture, which is part of the Kumagai-Gumi Array System for Strong Earthquake Motion (KASSEM) located on the Pacific coast in Miyagi and Fukushima Prefectures. Using acceleration waves obtained from earthquake observations, the amplification ratios of maximum acceleration amplitude and of root mean square acceleration amplitude which were based on the deepest observation point were estimated. Comparison between the seismic motion amplification characteristics of this study were made with the analyzed data at the Kamaishi-Mine (Kamaishi Miyagi Prefecture). The obtained results are as follows. The amplification ratios estimated from maximum acceleration amplitude and root mean square acceleration amplitude are almost constant in soft rock formations. However, amplification ratios at the surface in diluvium and alluvium are about three to four times larger than the ratios in soft rock formations. The amplification ratios estimated from root mean square acceleration amplitude are less dispersed than the ratios estimated from maximum acceleration amplitude. Comparing the results of this analysis with the results obtained at the Kamaishi-Mine, despite the difference in the rock types and the geologic formations at the observation points, there is a tendency for the amplification ratios at both points to be relatively small in the rock foundation and gradually increase toward the ground surface. (author)
International Nuclear Information System (INIS)
Healey, J.J.; Wu, S.T.; Murga, M.
1980-02-01
As part of the Phase I effort of the Seismic Safety Margins Research Program (SSMRP) being performed by the University of California Lawrence Livermore Laboratory for the US Nuclear Regulatory Commission, the basic objective of Subtask IV.1 (Structural Building Response Review) is to review and summarize current methods and data pertaining to seismic response calculations particularly as they relate to the objectives of the SSMRP. This material forms one component in the development of the overall computational methodology involving state of the art computations including explicit consideration of uncertainty and aimed at ultimately deriving estimates of the probability of radioactive releases due to seismic effects on nuclear power plant facilities
Response of sliding structures to seismic excitation: bibliographical study
International Nuclear Information System (INIS)
Sarh, K.; Duval, C.
1992-11-01
Calculation of the seismic response of structures on sliding supports involves the dual problem of ''non-linear'' and ''random'' dynamic behaviour. After a review of the non-linearities common in dynamics, slipping is compared with a hysteresis phenomenon. Simple examples are then used to present the Fokker-Planck equation and the equivalent linearization method. Finally, the methods for modification of the excitation spectrum intended for the engineering calculations are recalled. (authors). 21 figs., 23 refs
Evaluation of response factors for seismic probabilistic safety assessment of nuclear power plants
International Nuclear Information System (INIS)
Ebisawa, K.; Abe, K.; Muramatsu, K.; Itoh, M.; Kohno, K.; Tanaka, T.
1994-01-01
This paper presents a method for evaluating 'response factors' of components in nuclear power plants for use in a seismic probabilistic safety assessment (PSA). The response factor here is a measure of conservatism included in response calculations in seismic design analysis of components and is defined as a ratio of conservative design resonse to actual response. This method has the following characteristic features: (1) The components are classified into several groups based on the differences in their location and in the vibration models used in design response analyses; (2) the response factors are decomposed into subfactors corresponding to the stages of the seismic response analyses in the design practices; (3) the response factors for components are calculated as products of subfactors; (4) the subfactors are expressed either as a single value or as a function of parameters that influence the response of components. This paper describes the outline of this method and results from an application to a sample problem in which response factors were quantified for examples of components selected from the groups. (orig.)
International Nuclear Information System (INIS)
Hagiwara, Yutaka; Yamamoto, Kohsuke; Kawamoto, Yoji; Nakagawa, Masaki; Akiyama, Hiroshi
1998-01-01
Plastic shear-bending buckling under seismic loadings is one of the major problems in the structural design of FBR main vessels. Pseudo-dynamic and dynamic buckling tests of cylinders were performed in order to study the effects of nonlinear seismic response on buckling strength, ductility, and plastic response reduction. The buckling strength formulae and the rule for ductility factors both derived from static tests were confirmed to be valid for the tests under dynamic loads. The displacement-constant rule for response reduction effect was modified by acceleration amplification factor in order to maintain applicability for various spectral profiles of seismic excitations. The response reduction estimated by the proposed rule was reasonably conservative for all cases of the pseudo-dynamic and the dynamic tests. Finally, a seismic safety assessment rule was proposed for plastic shear-bending buckling of cylinders, which include the proposed response reduction rule. (author)
Seismic analysis of reactor exhaust-air Filter Compartment
International Nuclear Information System (INIS)
Gong, C.; Funderburk, E.L.; Jerrel, J.W.; Vashi, K.M.
1991-01-01
This paper presents the results of a scoping analysis for assessment of seismic adequacy of a Filter Compartments (FC) that is part of an Airborne Activity Confinement System (AACS) in K, L, and P Reactors at the Savannah River Site (SRS). For an expeditious assessment and to increase the possibility of showing the adequacy of the FC, the finite element model incorporated certain conceptual reinforcing modifications suggested by a previous study. The model also set the vertical displacements at zero at the interface between the FC and the rail dolly, upon which the FC rests by gravity. In addition, the rail-dolly was assumed to be rigid and rigidly attached to the rails. The analysis was performed using the dynamic modal superposition response spectra capability of the ABAQUS computer code. Certain modelling approximations and linearized representation of boundary conditions were employed for utilization of the code and the selected analysis capability. The analysis results showed that the FC stresses and deformations were within the yield limit and that the structural integrity of the FC and the operability of the filters can be preserved as required for the defined seismic event consistent with the linearization assumptions, modelling simplifications, and incorporation of the conceptual reinforcing modifications. However, the rail-dolly rigidity, the FC hold-down to the rails must be ensured for this scoping analysis to be valid. 2 refs
Seismic risk analysis for General Electric Plutonium Facility, Pleasanton, California
International Nuclear Information System (INIS)
1978-01-01
This report presents the results of a seismic risk analysis that focuses on all possible sources of seismic activity, with the exception of the postulated Verona Fault. The best estimate curve indicates that the Vallecitos facility will experience 30% g with a return period of roughly 130 years and 60% g with a return period of roughly 700 years
Determination of the NPP Cernavoda reactor building seismic response
International Nuclear Information System (INIS)
Krutzik, N.J.; Rotaru, I.; Bobei, M.; Mingiuc, C.; Serban, V.
1997-01-01
Seismic input for systems and equipment installed in buildings depends on: - the seismic movement in free field on site; - the building movement in the soil; - the building deflection. The percentage of the 3 movements for the system and equipment input, depends on the position of the systems and equipment inside the building as well on the type of the foundation soil. The type of the foundation soil is important because if it is stiff it transfers a lot of energy to the building, energy which amplify the movement of the building on the top. If the foundation soil is soft, it accommodates the overall movement of the building in the soil, amplifying the movement to lower levels and the building response is attenuated if a resonance phenomenon between the whole building movement and the seismic excitation does not exist. This input is given with the design floor response spectra (FRS), in the logarithmic scale and seismic anchor movement (SAM). The design floor response spectra for NPP Cernavoda U1 Nuclear Building were determined in several stages starting with simple models (STICK type) without twisting movement and ending with detailed 3-dimensional models. From the point of view of dynamic behavior, the Reactor Building can be considered to be made up of 4 sub-structures: the containment building, internal structures containing separate elements such as the reactor vault, the fuel transfer structure and itself. Each sub-structure has its own movement (some of the structures present also some local effects) which combines with the overall movement of the building in the soil and the seismic excitation produce the total movement so that the response spectrum for each point of the sub-structure is specific. One should note that for structures which also show the twisting effect, the selection of the points on the floor, for the determination on the response spectra, is an engineering decision so that the response should be relevant for the equipment installed on the
Seismic response of three-dimensional rockfill dams using the Indirect Boundary Element Method
International Nuclear Information System (INIS)
Sanchez-Sesma, Francisco J; Arellano-Guzman, Mauricio; Perez-Gavilan, Juan J; Suarez, Martha; Marengo-Mogollon, Humberto; Chaillat, Stephanie; Jaramillo, Juan Diego; Gomez, Juan; Iturraran-Viveros, Ursula; Rodriguez-Castellanos, Alejandro
2010-01-01
The Indirect Boundary Element Method (IBEM) is used to compute the seismic response of a three-dimensional rockfill dam model. The IBEM is based on a single layer integral representation of elastic fields in terms of the full-space Green function, or fundamental solution of the equations of dynamic elasticity, and the associated force densities along the boundaries. The method has been applied to simulate the ground motion in several configurations of surface geology. Moreover, the IBEM has been used as benchmark to test other procedures. We compute the seismic response of a three-dimensional rockfill dam model placed within a canyon that constitutes an irregularity on the surface of an elastic half-space. The rockfill is also assumed elastic with hysteretic damping to account for energy dissipation. Various types of incident waves are considered to analyze the physical characteristics of the response: symmetries, amplifications, impulse response and the like. Computations are performed in the frequency domain and lead to time response using Fourier analysis. In the present implementation a symmetrical model is used to test symmetries. The boundaries of each region are discretized into boundary elements whose size depends on the shortest wavelength, typically, six boundary segments per wavelength. Usually, the seismic response of rockfill dams is simulated using either finite elements (FEM) or finite differences (FDM). In most applications, commercial tools that combine features of these methods are used to assess the seismic response of the system for a given motion at the base of model. However, in order to consider realistic excitation of seismic waves with different incidence angles and azimuth we explore the IBEM.
Requalification analysis of a circular composite slab for seismic load
International Nuclear Information System (INIS)
Srinivasan, M.G.; Kot, C.A.
1993-01-01
The circular roof slab of an existing facility was analyzed to requalify the structure for supporting a significant seismic load that it was not originally designed for. The slab has a clear span of 66 ft and consists of a 48 in. thick reinforced concrete member and a steel liner plate. Besides a number of smaller penetrations, the slab contains two significant cutouts. The dominant load for the slab came from seismic excitation. It was characterized by a response spectrum with a peak spectral acceleration of 0.72 g in the vertical direction. The first part of the analysis showed that the nature of attachment between the liner plate and the reinforced concrete (RC) slab would justify assuming composite action between the two. A finite clement analysis, with the ANSYS code, was made to investigate the region surrounding the openings. As the reinforcement in the slab was quite inhomogeneous, it was necessary to determine the stresses in other areas of the slab also. These were obtained with closed form expressions. Finally it is shown that the strength design provisions of the Code Requirements for Nuclear Safety Related Concrete Structures were met by the reinforced concrete slab and the allowable stress provisions of the American National Standard for safety related steel structures in nuclear facilities were met by the liner plate. The composite action between the RC slab and the liner plate provides for the additional strength required to support the enhanced seismic load. The issues that complicated the analysis of this nontypical structure, i.e., composite action and nonlinear stiffness of RC sections, are discussed. It was possible to circumvent the difficulties by making conservative and simplifying assumptions. If design codes incorporate guidelines on practical methods for dynamic analysis of RC structures, some of the unneeded conservatism could be eliminated in future designs
Structural Analysis of Cabinet Support under Static and Seismic Loads
International Nuclear Information System (INIS)
Jung, Kwangsub; Lee, Sangjin; Oh, Jinho
2014-01-01
The cabinet support consists of frames including steel channels and steel square tubes. Four tap holes for screw bolts are located on the support frame of a steel channel to fix the cabinet on the support. The channels and square tubes are assembled by welded joints. The cabinet supports are installed on the outer walls of the reactor concrete island. The KEPIC code, MNF, is used for the design of the cabinet support. In this work, the structural integrity of the cabinet support is analyzed under consideration of static and seismic loads. A 3-D finite element model of the cabinet support was developed. The structural integrity of the cabinet support under postulated service loading conditions was evaluated through a static analysis, modal analysis, and response spectrum analysis. From the structural analysis results, it was concluded that the structural integrity of the cabinet support is guaranteed
Rescaled Range analysis of Induced Seismicity: rapid classification of clusters in seismic crisis
Bejar-Pizarro, M.; Perez Lopez, R.; Benito-Parejo, M.; Guardiola-Albert, C.; Herraiz, M.
2017-12-01
Different underground fluid operations, mainly gas storing, fracking and water pumping, can trigger Induced Seismicity (IS). This seismicity is normally featured by small-sized earthquakes (M<2.5), although particular cases reach magnitude as great as 5. It has been up for debate whether earthquakes greater than 5 can be triggered by IS or this level of magnitude only corresponds to tectonic earthquakes caused by stress change. Whatever the case, the characterization of IS for seismic clusters and seismic series recorded close but not into the gas storage, is still under discussion. Time-series of earthquakes obey non-linear patterns where the Hurst exponent describes the persistency or anti-persistency of the sequence. Natural seismic sequences have an H-exponent close to 0.7, which combined with the b-value time evolution during the time clusters, give us valuable information about the stationarity of the phenomena. Tectonic earthquakes consist in a main shock with a decay of time-occurrence of seismic shocks obeying the Omori's empirical law. On the contrary, IS does not exhibit a main shock and the time occurrence depends on the injection operations instead of on the tectonic energy released. In this context, the H-exponent can give information about the origin of the sequence. In 2013, a seismic crisis was declared from the Castor underground gas storing located off-shore in the Mediterranean Sea, close to the Northeastern Spanish cost. The greatest induced earthquake was 3.7. However, a 4.2 earthquake, probably of tectonic origin, occurred few days after the operations stopped. In this work, we have compared the H-exponent and the b-value time evolution according to the timeline of gas injection. Moreover, we have divided the seismic sequence into two groups: (1) Induced Seismicity and (2) Triggered Seismicity. The rescaled range analysis allows the differentiation between natural and induced seismicity and gives information about the persistency and long
Seismic Responses of a Cable-Stayed Bridge with Consideration of Uniform Temperature Load
Directory of Open Access Journals (Sweden)
Junjun Guo
2016-12-01
Full Text Available The effects of temperature load on the dynamic responses of cable-stayed bridges have attracted the attention of researchers in recent years. However, these investigations mainly focus on the influence of temperature on the dynamic characteristics of structures, such as vibration mode and frequency. This paper discusses the effects of uniform temperature changes on the seismic responses of a cable-stayed bridge. A three dimensional finite element model of a cable-stayed bridge using OpenSees is established for nonlinear time history analysis, and uniform temperature load is applied to the prototype bridge before the conducting of seismic excitation. Three ground motion records are selected from the PEER strong motion database based on the design spectrum. Case studies are then performed considering the varying temperature and the connections between the deck and pylons of the bridge. The result shows that the seismic responses of the bridge are significantly increased with the consideration of temperature load. Meanwhile, the types between the deck and pylon also have notable impacts on the seismic responses of the bridge with and without temperature changes. This research could provide a reference for designers during the design phase of cable-stayed brides.
Probability problems in seismic risk analysis and load combinations for nuclear power plants
International Nuclear Information System (INIS)
George, L.L.
1983-01-01
This workshop describes some probability problems in power plant reliability and maintenance analysis. The problems are seismic risk analysis, loss of load probability, load combinations, and load sharing. The seismic risk problem is to compute power plant reliability given an earthquake and the resulting risk. Component survival occurs if its peak random response to the earthquake does not exceed its strength. Power plant survival is a complicated Boolean function of component failures and survivals. The responses and strengths of components are dependent random processes, and the peak responses are maxima of random processes. The resulting risk is the expected cost of power plant failure
International Nuclear Information System (INIS)
Zaman, M.; Mamoon, S.M.
1989-01-01
Analysis of seismic response of structures located at a site with potential for soil liquefaction has drawn attention of many researchers. The topic is particularly important in the design of critical facilities like nuclear reactors and defense installations. This paper presents the results of a study involving evaluation of coupled seismic response of structures (model nuclear reactors) and characteristics of soil liquefaction at a site. The analysis procedure employed is based on the nonlinear finite element (FE) technique and accounts for the interaction effects due to a neighboring structure. Emphasis is given to the following features: prediction of spatial and temporal variation of pore water pressure; identification of the on-set of liquefaction based on the effective stress approach, and tracing the propagation of the liquefied zones with time and resulting response of the structures
Seismically induced accident sequence analysis of the advanced test reactor
International Nuclear Information System (INIS)
Khericha, S.T.; Henry, D.M.; Ravindra, M.K.; Hashimoto, P.S.; Griffin, M.J.; Tong, W.H.; Nafday, A.M.
1991-01-01
A seismic probabilistic risk assessment (PRA) was performed for the Department of Energy (DOE) Advanced Test Reactor (ATR) as part of the external events analysis. The risk from seismic events to the fuel in the core and in the fuel storage canal was evaluated. The key elements of this paper are the integration of seismically induced internal flood and internal fire, and the modeling of human error rates as a function of the magnitude of earthquake. The systems analysis was performed by EG ampersand G Idaho, Inc. and the fragility analysis and quantification were performed by EQE International, Inc. (EQE)
International Nuclear Information System (INIS)
Tanimoto, K.; Ito, T.; Fujita, K.; Kurihara, C.; Sawada, Y.; Sakurai, A.
1988-01-01
The paper presents the seismic response of reactor vessel of pool type LMFBR with fluid-structure interaction. The reactor vessel has bottom support arrangement, the same core support system as Super-Phenix in France. Due to the bottom support arrangement, the level of core support is lower than that of the side support arrangement. So, in this reactor vessel, the displacement of the core top tends to increase because of the core's rocking. In this study, we investigated the vibration and seismic response characteristics of the reactor vessel. Therefore, the seismic experiments were carried out using one-eighth scale model and the seismic response including FSI and sloshing were investigated. From this study, the effect of liquid on the vibration characteristics and the seismic response characteristics of reactor vessel were clarified and sloshing characteristics were also clarified. It was confirmed that FEM analysis with FSI can reproduce the seismic behavior of the reactor vessel and is applicable to seismic design of the pool type LMFBR with bottom support arrangement. (author). 5 refs, 14 figs, 2 tabs
Seismic analysis of a nonlinear airlock system
International Nuclear Information System (INIS)
Huang, S.N.
1983-01-01
The containment equipment airlock door of the Fast Flux Test Facility utilizes screw-type actuators as a push-pull mechanism for closing and opening operations. Special design features were used to protect these actuators from pressure differential loading. These made the door behave as a nonlinear system during a seismic event. Seismic analyses, utilizing the time history method, were conducted to determine the seismic loads on these scew-type actuators. Several sizes of actuators were examined. Procedures for determining the final optimum design are discussed in detail
Floor response spectra of WWER-1000, NPP Kozloduy generated from local seismic excitation
International Nuclear Information System (INIS)
Bojadziev, Z.; Kostov, M.
1996-01-01
The seismic review level characteristics for the Kozloduy NPP site were set to 0.2 g and a respective free field acceleration response spectra were derived after a profound site conformation project. Accordingly a separate investigation is recommended for local seismic excitation. The goals of the analyses are: to define the seismic motion characteristics from local seismic sources; to perform structural analyses and in-structure spectra generation for local seismic excitation; and to compare the forces (spectra) from local events with those generated as seismic design review basis
Seismic Safety Program: Ground motion and structural response
Energy Technology Data Exchange (ETDEWEB)
1993-05-01
In 1964, John A. Blume & Associates Research Division (Blume) began a broad-range structural response program to assist the Nevada Operations Office of the US Atomic Energy Commission (AEC) in ensuring the continued safe conduct of underground nuclear detonation testing at the Nevada Test Site (NTS) and elsewhere. Blume`s long experience in earthquake engineering provided a general basis for the program, but much more specialized knowledge was required for the AEC`s purposes. Over the next 24 years Blume conducted a major research program to provide essential understanding of the detailed nature of the response of structures to dynamic loads such as those imposed by seismic wave propagation. The program`s results have been embodied in a prediction technology which has served to provide reliable advanced knowledge of the probable effects of seismic ground motion on all kinds of structures, for use in earthquake engineering and in building codes as well as for the continuing needs of the US Department of Energy`s Nevada Operations Office (DOE/NV). This report is primarily an accounting of the Blume work, beginning with the setting in 1964 and the perception of the program needs as envisioned by Dr. John A. Blume. Subsequent chapters describe the structural response program in detail and the structural prediction procedures which resulted; the intensive data acquisition program which, as is discussed at some length, relied heavily on the contributions of other consultant-contractors in the DOE/NV Seismic Safety Support Program; laboratory and field studies to provide data on building elements and structures subjected to dynamic loads from sources ranging from testing machines to earthquakes; structural response activities undertaken for testing at the NTS and for off-NTS underground nuclear detonations; and concluding with an account of corollary studies including effects of natural forces and of related studies on building response.
Seismic analysis of liquid storage container in nuclear reactors
International Nuclear Information System (INIS)
Zhang Zhengming; He Shuyan; Xu Ming
2007-01-01
Seismic analysis of liquid storage containers is always difficult in the seismic design of nuclear reactor equipment. The main reason is that the liquid will generate significant seismic loads under earthquake. These dynamic liquid loads usually form the main source of the stresses in the container. For this kind of structure-fluid coupling problem, some simplified theoretical methods were usually used previously. But this cannot satisfy the requirements of engineering design. The Finite Element Method, which is now full developed and very useful for the structural analysis, is still not mature for the structure-fluid coupling problem. This paper introduces a method suitable for engineering mechanical analysis. Combining theoretical analysis of the dynamic liquid loads and finite element analysis of the structure together, this method can give practical solutions in the seismic design of liquid storage containers
Inertial Effects on Finite Length Pipe Seismic Response
Directory of Open Access Journals (Sweden)
Virginia Corrado
2012-01-01
Full Text Available A seismic analysis for soil-pipe interaction which accounts for length and constraining conditions at the ends of a continuous pipe is developed. The Winkler model is used to schematize the soil-structure interaction. The approach is focused on axial strains, since bending strains in a buried pipe due to the wave propagation are typically a second-order effect. Unlike many works, the inertial terms are considered in solving equations. Accurate numerical simulations are carried out to show the influence of pipe length and constraint conditions on the pipe seismic strain. The obtained results are compared with results inferred from other models present in the literature. For free-end pipelines, inertial effects have significant influence only for short length. On the contrary, their influence is always important for pinned pipes. Numerical simulations show that a simple rigid model can be used for free-end pipes, whereas pinned pipes need more accurate models.
Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs
Energy Technology Data Exchange (ETDEWEB)
Ile, Nicolas; Frau, Alberto, E-mail: alberto.frau@cea.fr
2017-04-01
Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.
Use of response envelopes for seismic margin assessment of reinforced concrete walls and slabs
International Nuclear Information System (INIS)
Ile, Nicolas; Frau, Alberto
2017-01-01
Highlights: • Proposal of a method for application of the elliptical envelope to RC shell elements. • Proposal of new algorithms for the seismic margin evaluation for RC shell elements. • Verification of a RC wall 3D structure, using the proposed assessment approach. - Abstract: Seismic safety evaluations of existing nuclear facilities are usually based on the assumption of structural linearity. For the design basis earthquake (DBE), it is reasonable to apply a conventional evaluation of the seismic safety of building structures and carry out a linear elastic analysis to assess the load effects on structural elements. Estimating the seismic capacity of a structural element requires an estimation of the critical combination of responses acting in this structural element and compare this combination with the capacity of the element. By exploiting the response-spectrum-based procedure for predicting the response envelopes in linear structures formulated by Menun and Der Kiureghian (2000a), algorithms are developed for the seismic margin assessment of reinforced concrete shell finite elements. These algorithms facilitate the comparison of the response-spectrum-based envelopes to prescribed capacity surfaces for the purpose of assessing the safety margin of this kind of structures. The practical application of elliptical response envelopes in case of shell finite elements is based on the use of layer models such as those developed by Marti (1990), which transfer the generalized stress field to three layers under the assumption that the two outer layers carry membrane forces and the internal layer carries only the out-of-plane shears. The utility of the assessment approach is discussed with reference to a case study of a 3D structure made of reinforced concrete walls.
Full scale testing for investigation of wind turbine seismic response
Energy Technology Data Exchange (ETDEWEB)
Prowell, I.; Veletzos, M.; Elgamal, A. [California Univ., San Diego, CA (United States). Dept. of Structural Engineering
2008-07-01
In 2007, much of the growth in wind energy development was concentrated in North America and Asia, two regions which periodically experience strong earthquakes that may impact the final turbine design. As such, rational prediction of seismic hazards must be considered in order to maintain and enhance the ability of wind power to compete economically with other energy sources. In response to this challenge, researchers at the University of California, San Diego (UCSD) have experimentally investigated wind turbines to gain an understanding of expected earthquake forces. This paper described the experimental setup for a full scale shake table test of a 65 kW wind turbine. The turbine was excited perpendicular to the axis of the rotor with a seismic base shaking record scaled to various levels. The data was analyzed using simple but effective procedures to provide insight into the observed structural damping of the wind turbine. The experimental investigation showed that full scale seismic testing of wind turbines is possible and can provide valuable insight into dynamic behaviour of wind turbines. The results can be used to develop a more accurate picture of how wind turbines are impacted by earthquakes. The data regarding the low observed super-structure damping provides a basis for calibration and further development of verified design procedures. 20 refs., 3 tabs.
Seismic Safety Margins Research Program. Phase I final report - Subsystem response (Project V)
International Nuclear Information System (INIS)
Shieh, L.C.; Chuang, T.Y.; O'Connell, W.J.
1981-10-01
This document reports on (1) the computation of the responses of subsystems, given the input subsystem support motion for components and systems whose failure can lead to an accident sequence (radioactive release), and (2) the results of a sensitivity study undertaken to determine the contributions of the several links in the seismic methodology chain (SMC) - seismic input (SI), soil-structure interaction (SSI), structure response (STR), and subsystem response (SUB) - to the uncertainty in subsystem response. For the singly supported subsystems (e.g., pumps, turbines, electrical control panels, etc.), we used the spectral acceleration response of the structure at the point where the subsystem components were mounted. For the multiple supported subsystems, we developed 13 piping models of five safety-related systems, and then used the pseudostatic-mode method with multisupport input motion to compute the response parameters in terms of the parameters used in the fragility descriptions (i.e., peak resultant accelerations for valves and peak resultant moments for piping). Damping and frequency were varied to represent the sources of modeling and random uncertainty. Two codes were developed: a modified version of SAPIV which assembles the piping supports into groups depending on the support's location relative to the attached structure, and SAPPAC a stand-alone modular program from which the time-history analysis module is extracted. On the basis of our sensitivity study, we determined that the variability in the combined soil-structure interaction, structural response, and subsystem response areas contribute more to uncertainty in subsystem response than does the variability in the seismic input area, assuming an earthquake within the limited peak ground acceleration range, i.e., 0.15 to 0.30g. The seismic input variations were in terms of different earthquake time histories. (author)
Seismic margin analysis technique for nuclear power plant structures
International Nuclear Information System (INIS)
Seo, Jeong Moon; Choi, In Kil
2001-04-01
In general, the Seismic Probabilistic Risk Assessment (SPRA) and the Seismic Margin Assessment(SAM) are used for the evaluation of realistic seismic capacity of nuclear power plant structures. Seismic PRA is a systematic process to evaluate the seismic safety of nuclear power plant. In our country, SPRA has been used to perform the probabilistic safety assessment for the earthquake event. SMA is a simple and cost effective manner to quantify the seismic margin of individual structural elements. This study was performed to improve the reliability of SMA results and to confirm the assessment procedure. To achieve this goal, review for the current status of the techniques and procedures was performed. Two methodologies, CDFM (Conservative Deterministic Failure Margin) sponsored by NRC and FA (Fragility Analysis) sponsored by EPRI, were developed for the seismic margin review of NPP structures. FA method was originally developed for Seismic PRA. CDFM approach is more amenable to use by experienced design engineers including utility staff design engineers. In this study, detailed review on the procedures of CDFM and FA methodology was performed
New developments in seismic analysis of primary and secondary systems
International Nuclear Information System (INIS)
Gupta, A.K.
1984-01-01
Primary and secondary systems often must be analyzed using decoupled models. This paper presents recent advances made at NCSU in the seismic analysis of these systems. Algorithms are presented by which coupled mode shapes and frequencies can be evaluated without performing a new eigenvalue solution, given the mode shapes and frequencies of the decoupled models. Simple and accurate equations are presented to predict changes in frequencies and responses. With the coupled mode shapes and frequencies, one can obtain any primary or secondary response directly from the input spectrum. Alternatively, one can develop instructure spectra at various locations in the primary system accounting for the primary-secondary system interaction. Correlation between the support motions is also generated. Equations are presented for evaluating complex mode shapes and frequencies of coupled systems when due to unequal damping values of primary and secondary systems, the coupled system becomes nonproportionally damped. Recent progress, in case of tuned systems is also reported
The seismic response and floor spectra of OL3 NPP buildings in Finland
International Nuclear Information System (INIS)
Pentti Varpasuo
2005-01-01
The purpose of the present work is the computation of seismic response and floor spectra of the nuclear power plant OL3 buildings in Olkiluoto. The following OL3 plant buildings were included in the analysis: 1. the Reactor Building UJA/UJB; 2. the Safeguard Buildings UJH/UJK 1-4; 3. and the Fuel Building UFA The in-structure spectra were generated using the ground motion response spectra documented in YVL GUIDE 2.6 'Seismic events at nuclear power plants' issued by Finnish Centre of Radiation Protection. The floor spectra were computed for the following equipment damping values: 2%, 4%, 7%, and 10%. The joint model for the plant buildings was generated. All analyses were linear and the direct time integration method was used with time step of 0.001 sec. All response runs were carried out with MSC/Nastran general purpose structural analysis program. The development of floor spectra has been carried out in accordance with the US NRC -Regulatory Guide 1.122: 'Development of Floor Design Response Spectra for Seismic Design of Floor-Supported Equipment or Components'. The response results show that the dominant frequencies of the reactor building are located around 5 Hz in frequency space and that the typical amplification of spectral peaks for 4% damping is from 8 -10 times when compared to peak ground acceleration. (authors)
Evaluation of Fourier integral. Spectral analysis of seismic events
International Nuclear Information System (INIS)
Chitaru, Cristian; Enescu, Dumitru
2003-01-01
Spectral analysis of seismic events represents a method for great earthquake prediction. The seismic signal is not a sinusoidal signal; for this, it is necessary to find a method for best approximation of real signal with a sinusoidal signal. The 'Quanterra' broadband station allows the data access in numerical and/or graphical forms. With the numerical form we can easily make a computer program (MSOFFICE-EXCEL) for spectral analysis. (authors)
Comparison of elastic and inelastic seismic response of high temperature piping systems
International Nuclear Information System (INIS)
Thomas, F.M.; McCabe, S.L.; Liu, Y.
1994-01-01
A study of high temperature power piping systems is presented. The response of the piping systems is determined when subjected to seismic disturbances. Two piping systems are presented, a main steam line, and a cold reheat line. Each of the piping systems are modeled using the ANSYS computer program and two analyses are performed on each piping system. First, each piping system is subjected to a seismic disturbance and the pipe material is assumed to remain linear and elastic. Next the analysis is repeated for each piping system when the pipe material is modeled as having elastic-plastic behavior. The results of the linear elastic analysis and elastic-plastic analysis are compared for each of the two pipe models. The pipe stresses, strains, and displacements, are compared. These comparisons are made so that the effect of the material yielding can be determined and to access what error is made when a linear analysis is performed on a system that yields
International Nuclear Information System (INIS)
Hirose, Jiro; Muramatsu, Ken
2002-03-01
This report presents a study on the procedures for the determination of scenario earthquakes for seismic design of nuclear power plants (NPPs) based on probabilistic seismic hazard analysis (PSHA). In the recent years, the use of PSHA, which is a part of seismic probabilistic safety assessment (PSA), to determine the design basis earthquake motions for NPPs has been proposed. The identified earthquakes are called probability-based scenario earthquakes (PBSEs). The concept of PBSEs originates both from the study of US NRC and from Ishikawa and Kameda. The assessment of PBSEs is composed of seismic hazard analysis and identification of dominant earthquakes. The objectives of this study are to formulate the concept of PBSEs and to examine the procedures for determining the PBSEs for a domestic NPP site. This report consists of three parts, namely, procedures to compile analytical conditions for PBSEs, an assessment to identify PBSEs for a model site using the Ishikawa's concept and the examination of uncertainties involved in analytical conditions. The results obtained from the examination of PBSEs using Ishikawa's concept are as follows. (a) Since PBSEs are expressed by hazard-consistent magnitude and distance in terms of a prescribed reference probability, it is easy to obtain a concrete image of earthquakes that determine the ground response spectrum to be considered in the design of NPPs. (b) Source contribution factors provide the information on the importance of the earthquake source regions and/or active faults, and allows the selection of a couple of PBSEs based on their importance to the site. (c) Since analytical conditions involve uncertainty, sensitivity analyses on uncertainties that would affect seismic hazard curves and identification of PBSEs were performed on various aspects and provided useful insights for assessment of PBSEs. A result from this sensitivity analysis was that, although the difference in selection of attenuation equations led to a
Advanced Seismic Fragility Modeling using Nonlinear Soil-Structure Interaction Analysis
Energy Technology Data Exchange (ETDEWEB)
Bolisetti, Chandu [Idaho National Lab. (INL), Idaho Falls, ID (United States); Coleman, Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Talaat, Mohamed [Simpson-Gupertz & Heger, Waltham, MA (United States); Hashimoto, Philip [Simpson-Gupertz & Heger, Waltham, MA (United States)
2015-09-01
The goal of this effort is to compare the seismic fragilities of a nuclear power plant system obtained by a traditional seismic probabilistic risk assessment (SPRA) and an advanced SPRA that utilizes Nonlinear Soil-Structure Interaction (NLSSI) analysis. Soil-structure interaction (SSI) response analysis for a traditional SPRA involves the linear analysis, which ignores geometric nonlinearities (i.e., soil and structure are glued together and the soil material undergoes tension when the structure uplifts). The NLSSI analysis will consider geometric nonlinearities.
International Nuclear Information System (INIS)
Contri, P.
1996-01-01
The analysis described in this report deals with a numerical procedure aimed for the assessment of a methodology for the optimal organization of data collection, in the context of seismic requalification of structures and components of existing nuclear power plants. The presented procedure has quite a general application and an example was chosen for the Paks NPP where seismic requalification is in progress. The assessment was carried out in reference to the following main tasks: structure and soil data analysis; numerical model generation; deterministic dynamic analysis description; reliability analysis framework discussion; transfer function calculation via response surface approach; and the sensitivity evaluation
Directory of Open Access Journals (Sweden)
Li Tian
2010-01-01
Full Text Available The behavior of power transmission tower-line system subjected to spatially varying base excitations is studied in this paper. The transmission towers are modeled by beam elements while the transmission lines are modeled by cable elements that account for the nonlinear geometry of the cables. The real multistation data from SMART-1 are used to analyze the system response subjected to spatially varying ground motions. The seismic input waves for vertical and horizontal ground motions are also generated based on the Code for Design of Seismic of Electrical Installations. Both the incoherency of seismic waves and wave travel effects are accounted for. The nonlinear time history analytical method is used in the analysis. The effects of boundary conditions, ground motion spatial variations, the incident angle of the seismic wave, coherency loss, and wave travel on the system are investigated. The results show that the uniform ground motion at all supports of system does not provide the most critical case for the response calculations.
International Nuclear Information System (INIS)
Ghiocel, Dan M.; Wilson, Paul R.; Thomas, Gary G.; Stevenson, John D.
1998-01-01
The paper discusses methodological aspects involved in a probabilistic seismic soil-structure interaction (SSI) analysis for a Seismic Probabilistic Risk Assessment (SPRA) review. An example of an Eastern US nuclear power plant (NPP) is presented. The approach presented herein follows the current practice of the Individual Plant Examination for External Events (IPEEE) program in the US. The NPP is founded on a relatively soft soil deposit, and thus the SSI effects on seismic responses are significant. Probabilistic models used for the idealization of the seismic excitation and the surrounding soil deposit are described. Using a lognormal format, computed random variability effects were combined with those proposed in the SPRA methodology guidelines. Probabilistic floor response spectra and structural fragilities for different NPP buildings were computed. Structural capacities were determined following the current practice which assumes independent median safety factors for strength and inelastic absorption. Limitations of the IPEEE practice for performing SPRA are discussed and alternate procedures, more rigorous and simple to implement, are suggested
Seismic rehabilitation and analysis of Chaohe earth dam
Fu, Lei; Zeng, Xiangwu
2005-12-01
Stability of earth dams during earthquakes has been a major concern for geotechnical engineers in seismic active regions. Liquefaction induced slope failure occurred at the upstream slope of a major earth dam in the suburb of Beijing, China, during the 1976 Tangshan Earthquake. The gravelly soil with loose initial condition liquefied under relatively small ground vibration. In recent years, a major seismic rehabilitation project was carried out on a similar earth dam nearby using dumped quarry stone. Seismic stability analysis was carried out using model test, finite element simulation, and pseudo-static slope stability program after taking into account the influence of excess pore pressure.
On the response of large dams to incoherent seismic excitation
International Nuclear Information System (INIS)
Ramadan, O.; Novak, M.
1993-01-01
An intensive parametric study was conducted to investigate the response of concrete gravity dams to horizontal, spatially variable seismic ground motions. Both segmented dams consisting of separate blocks, or monoliths, and continuous monolithic dams are considered. The study includes the effects of various parameters on system natural frequencies, vibration modes, modal displacement ratios, as well as dam displacements and internal stresses due to spatially variable ground motions. The dam analytical model, and dam response to incoherent ground motions are described. The results show that the dam vibrates almost as a rigid body under the fully correlated waves, but bends and twists significantly under the spatially correlated motions. Dam-foundation interaction magnifies the low frequency components of the dam response, more so for a full reservoir, but decreases the high frequency components. For long dams, the effects of spatially incoherent ground motions are qualitatively different and can be much greater than those due to surface travelling waves. 3 refs., 3 figs
Seismic soil structure interaction: analysis and centrifuge model studies
International Nuclear Information System (INIS)
Finn, W.D.L.; Ledbetter, R.H.; Beratan, L.L.
1985-01-01
A method for non-linear dynamic effective stress analysis is introduced which is applicable to soil-structure interaction problems. Full interaction including slip between structure and foundation is taken into account and the major factors are included which must be considered when computing dynamic soil response. An experimental investigation was conducted using simulated earthquake tests on centrifuged geotechnical models in order to obtain prototype response data of foundation soils carrying both surface and embedded structures and to validate the dynamic effective stress analysis. Horizontal and vertical accelerations were measured at various points on structures and in the sand foundation. Seismically-induced pore water pressure changes were also measured at various locations in the foundation. Computer plots of the data were obtained while the centrifuge was in flight and representative samples are presented. The results show clearly the pronounced effect that increasing pore water pressures have on dynamic response. It is demonstrated that a coherent picture of dynamic response of soil-structure systems is provided by dynamic effective stress non-linear analysis. Based on preliminary results, it appears that the pore water pressure effects can be predicted
Seismic soil-structure interaction: Analysis and centrifuge model studies
International Nuclear Information System (INIS)
Finn, W.D.L.; Ledbetter, R.H.; Beratan, L.L.
1986-01-01
A method for nonlinear dynamic effective stress analysis applicable to soil-structure interaction problems is introduced. Full interaction including slip between structure and foundation is taken into account and the major factors that must be considered when computing dynamic soil response are included. An experimental investigation using simulated earthquake tests on centrifuged geotechnical models was conducted to obtain prototype response data of foundation soils carrying both surface and embedded structures and to validate the dynamic effective stress analysis. The centrifuge tests were conducted in the Geotechnical Centrifuge at Cambridge University, England. Horizontal and vertical accelerations were measured at various points on structures and in the sand foundation. Seismically induced pore water pressure changes were also measured at various locations in the foundation. Computer plots of the data were obtained while the centrifuge was in flight and representative samples are presented. The results clearly show the pronounced effect of increasing pore water pressures on dynamic response. It is demonstrated that a coherent picture of dynamic response of soil-structure systems is provided by dynamic effective stress nonlinear analysis. On the basis of preliminary results, it appears that the effects of pore water pressure can be predicted. (orig.)
Nucelar reactor seismic safety analysis techniques
International Nuclear Information System (INIS)
Cummings, G.E.; Wells, J.E.; Lewis, L.C.
1979-04-01
In order to provide insights into the seismic safety requirements for nuclear power plants, a probabilistic based systems model and computational procedure have been developed. This model and computational procedure will be used to identify where data and modeling uncertainties need to be decreased by studying the effect of these uncertainties on the probability of radioactive release and the probability of failure of various structures, systems, and components. From the estimates of failure and release probabilities and their uncertainties the most sensitive steps in the seismic methodologies can be identified. In addition, the procedure will measure the uncertainty due to random occurrences, e.g. seismic event probabilities, material property variability, etc. The paper discusses the elements of this systems model and computational procedure, the event-tree/fault-tree development, and the statistical techniques to be employed
3-D seismic response of a base-isolated fast reactor
International Nuclear Information System (INIS)
Kitamura, S.; Morishita, M.; Iwata, K.
1992-01-01
This paper describes a 3-D response analysis methodology development and its application to a base-isolated fast breeder reactor (FBR) plant. At first, studies on application of a base-isolation system to an FBR plant were performed to identify a range of appropriate characteristics of the system. A response analysis method was developed based on mathematical models for the restoring force characteristics of several types of the systems. A series of shaking table tests using a small scale model was carried out to verify the analysis method. A good agreement was seen between the test and analysis results in terms of the horizontal and vertical responses. Parametric studies were then made to assess the effects of various factors which might be influential to the seismic response of the system. Moreover, the method was applied to evaluate three-dimensional response of the base-isolated FBR. (author)
GUI program to compute probabilistic seismic hazard analysis
International Nuclear Information System (INIS)
Shin, Jin Soo; Chi, H. C.; Cho, J. C.; Park, J. H.; Kim, K. G.; Im, I. S.
2005-12-01
The first stage of development of program to compute probabilistic seismic hazard is completed based on Graphic User Interface (GUI). The main program consists of three part - the data input processes, probabilistic seismic hazard analysis and result output processes. The first part has developed and others are developing now in this term. The probabilistic seismic hazard analysis needs various input data which represent attenuation formulae, seismic zoning map, and earthquake event catalog. The input procedure of previous programs based on text interface take a much time to prepare the data. The data cannot be checked directly on screen to prevent input erroneously in existing methods. The new program simplifies the input process and enable to check the data graphically in order to minimize the artificial error within the limits of the possibility
GUI program to compute probabilistic seismic hazard analysis
International Nuclear Information System (INIS)
Shin, Jin Soo; Chi, H. C.; Cho, J. C.; Park, J. H.; Kim, K. G.; Im, I. S.
2006-12-01
The development of program to compute probabilistic seismic hazard is completed based on Graphic User Interface(GUI). The main program consists of three part - the data input processes, probabilistic seismic hazard analysis and result output processes. The probabilistic seismic hazard analysis needs various input data which represent attenuation formulae, seismic zoning map, and earthquake event catalog. The input procedure of previous programs based on text interface take a much time to prepare the data. The data cannot be checked directly on screen to prevent input erroneously in existing methods. The new program simplifies the input process and enable to check the data graphically in order to minimize the artificial error within limits of the possibility
Seismic analysis for translational failure of landfills with retaining walls.
Feng, Shi-Jin; Gao, Li-Ya
2010-11-01
In the seismic impact zone, seismic force can be a major triggering mechanism for translational failures of landfills. The scope of this paper is to develop a three-part wedge method for seismic analysis of translational failures of landfills with retaining walls. The approximate solution of the factor of safety can be calculated. Unlike previous conventional limit equilibrium methods, the new method is capable of revealing the effects of both the solid waste shear strength and the retaining wall on the translational failures of landfills during earthquake. Parameter studies of the developed method show that the factor of safety decreases with the increase of the seismic coefficient, while it increases quickly with the increase of the minimum friction angle beneath waste mass for various horizontal seismic coefficients. Increasing the minimum friction angle beneath the waste mass appears to be more effective than any other parameters for increasing the factor of safety under the considered condition. Thus, selecting liner materials with higher friction angle will considerably reduce the potential for translational failures of landfills during earthquake. The factor of safety gradually increases with the increase of the height of retaining wall for various horizontal seismic coefficients. A higher retaining wall is beneficial to the seismic stability of the landfill. Simply ignoring the retaining wall will lead to serious underestimation of the factor of safety. Besides, the approximate solution of the yield acceleration coefficient of the landfill is also presented based on the calculated method. Copyright © 2010 Elsevier Ltd. All rights reserved.
A seismic analysis of nuclear power plant components subjected to multi-excitations of earthquakes
International Nuclear Information System (INIS)
Ichiki, T.; Matsumoto, T.; Gunyasu, K.
1977-01-01
In this analysis, the modal analysis methods are used to determine the seismic responses of structural systems instead of the direct integration method. These results have been compared with some kinds of other analytical methods, and investigated the accuracy of numerical results of these analysis, applying to such components as Reactor Pressure Vessel and Reactor Internals of an actual plant. The results of this method of analysis are summarized as follows: (1) one of the seismic analysis methods concerning systems subjected to multi-excitations of earthquakes has been presented to the conference of JSME. Although the analytical theory presented to that conference is correct, it has a serious problem about the accuracy of numerical results. This computer program and theory cannot be used practically due to the time necessary to calculate. However, the method described in this paper overcomes those serious problems stated above and has no problem about the computer time and precision. So, it is possible to apply this method to the seismic design of an actual nuclear power plant practically. (2) The feed back effects of the seismic responses of Reactor Internals to Reactor Building are considered so small that we can separate the model of Reactor Internals from Reactor Building. (3) The results of seismic response of Reactor Internals are fairly consistent with those obtained from the model coupled with Reactor Building. (4) This analysis method can be extended to the model of Reactor Internals subjected to more than two random excitations of earthquakes. (5) It is possible that this analysis method is also applied to the seismic analysis of such three-dimensional systems as piping systems subjected to multi-excitations of earthquakes
ESAA environment for seismic activity analysis
International Nuclear Information System (INIS)
Zhang Shuyu; Hao Bailin.
1994-09-01
ESAA is an X-window based, graphical and interactive, software system for analyzing seismic activity, using the earthquake catalogues of a given region as input. Basic design idea and structure of this system, as well as the progress in its implementation are reported. (author). 12 refs
Numerical calculation models of the elastoplastic response of a structure under seismic action
International Nuclear Information System (INIS)
Edjtemai, Nima.
1982-06-01
Two digital calculation models developed in this work have made it possible to analyze the exact dynamic behaviour of ductile structures with one or several degrees of liberty, during earthquakes. With the first model, response spectra were built in the linear and non-linear fields for different absorption and ductility values and two types of seismic accelerograms. The comparative study of these spectra made it possible to check the validity of certain hypotheses suggested for the construction of elastoplastic spectra from corresponding linear spectra. A simplified method of non-linear seismic calculation based on the modal analysis and the spectra of elastoplastic response was then applied to structures with a varying number of degrees of liberty. The results obtained in this manner were compared with those provided by an exact calculation provided by the second digital model developed by us [fr
Major structural response methods used in the seismic safety margins research program
International Nuclear Information System (INIS)
Chou, C.K.; Lo, T.; Vagliente, V.
1979-01-01
In order to evaluate the conservatisms in present nuclear power plant seismic safety requirements, a probabilistic based systems model is being developed. This model will also be used to develop improved requirements. In Phase I of the Seismic Safety Margins Research Program (SSMRP), this methodology will be developed for a specific nuclear power plant and used to perform probabilistic sensitivity studies to gain engineering insights into seismic safety requirements. Random variables in the structural response analysis area, or parameters which cause uncertainty in the response, are discussed and classified into three categories; i.e., material properties, structural dynamic characteristics and related modeling techniques, and analytical methods. The sensitivity studies are grouped into two categories; deterministic and probabilistic. In a system analysis, transfer functions in simple form are needed since there are too many responses which have to be calculated in a Monte Carlo simulation to use the usual straightforward calculation approach. Therefore, the development of these simple transfer functions is one of the important tasks in SSMRP. Simplified as well as classical transfer functions are discussed
Dinske, C.; Langenbruch, C.; Shapiro, S. A.
2017-12-01
We investigate seismicity related to hydrothermal systems in Germany and Italy, focussing on temporal changes of seismicity rates. Our analysis was motivated by numerical simulations The modeling of stress changes caused by the injection and production of fluid revealed that seismicity rates decrease on a long-term perspective which is not observed in the considered case studies. We analyze the waiting time distributions of the seismic events in both time domain (inter event times) and fluid volume domain (inter event volume). We find clear indications that the observed seismicity comprises two components: (1) seismicity that is directly triggered by production and re-injection of fluid, i.e. induced events, and (2) seismicity that is triggered by earthquake interactions, i.e. aftershock triggering. In order to better constrain our numerical simulations using the observed induced seismicity we apply catalog declustering to seperate the two components. We use the magnitude-dependent space-time windowing approach introduced by Gardner and Knopoff (1974) and test several published algorithms to calculate the space-time windows. After declustering, we conclude that the different hydrothermal reservoirs show a comparable seismic response to the circulation of fluid and additional triggering by earthquake interactions. The declustered catalogs contain approximately 50 per cent of the number of events in the original catalogs. We then perform ETAS (Epidemic Type Aftershock; Ogata, 1986, 1988) modeling for two reasons. First, we want to know whether the different reservoirs are also comparable regarding earthquake interaction patterns. Second, if we identify systematic patterns, ETAS modeling can contribute to forecast seismicity during production of geothermal energy. We find that stationary ETAS models cannot accurately capture real seismicity rate changes. One reason for this finding is given by the rate of observed induced events which is not constant over time. Hence
Influence of fabric anisotropy on seismic responses of foundations
Directory of Open Access Journals (Sweden)
Jin Qin
2015-04-01
Full Text Available Earthquakes, as one of the well-known natural disasters, are highly destructive and unpredictable. Foundation failure due to liquefaction induced by earthquakes can cause casualties as well as significant damage to the building itself. Fabric anisotropy of soil grains is considered to be an important factor in dynamic soil response based on previous researches and laboratory tests. However, the limited availability of real physical data makes it less persuasive. In this study, a shake table installed on a geotechnical centrifuge is used to provide the designed seismic motions, and therefore, to simulate the realistic earthquake motion to foundations. Important parameters in the responses such as acceleration, excess pore pressure and deformation are evaluated to investigate the influence. Implications for design are also discussed.
Seismic analysis of fuel and target assemblies at a production reactor
International Nuclear Information System (INIS)
Braverman, J.I.; Wang, Y.K.
1991-01-01
This paper describes the unique modeling and analysis considerations used to assess the seismic adequacy of the fuel and target assemblies in a production reactor at Savannah River Site. This confirmatory analysis was necessary to provide assurance that the reactor can operate safely during a seismic event and be brought to a safe shutdown condition. The plant which was originally designed in the 1950's required to be assessed to more current seismic criteria. The design of the reactor internals and the magnitude of the structural responses enabled the use of a linear elastic dynamic analysis. A seismic analysis was performed using a finite element model consisting of the fuel and target assemblies, reactor tank, and a portion of the concrete structure supporting the reactor tank. The effects of submergence of the fuel and target assemblies in the water contained within the reactor tank can have a significant effect on their seismic response. Thus, the model included hydrodynamic fluid coupling effects between the assemblies and the reactor tank. Fluid coupling mass terms were based on formulations for solid bodies immersed in incompressible and frictionless fluids. The potential effects of gap conditions were also assessed in this evaluation. 5 refs., 6 figs., 1 tab
Seismic response of structures by the response spectrum method
International Nuclear Information System (INIS)
Hadjian, A.H.
1981-01-01
The problems of the acceleration profile at the lower elevations of cantilever structures and the response of relatively rigid structures are explored. It is shown that the use of the conventional methods for the above problems provide very approximate results. An alternate combination of the modal responses is proposed that not only resolves the above problems but also provides better estimates of response for the complete range of structure frequencies. The procedure treats the relative and rigid body responses separately and then appropriately combines the two results. For the rigid range of frequencies (fundamental frequencies greater than about 2 Hz), the proposed procedure does not encounter any numerical difficulties because of the additive nature of the component responses; however, the application of the proposed procedure for very flexible structures causes accuracy problems since the rigid body effects tend to be subtractive from the flexural response of about equal magnitude. For this latter class of problems, the conventional approach of modal combination provides adequate results and avoids the above mentioned numerical difficulties. (orig.)
Scram and nonlinear reactor system seismic analysis for the Fast Flux Test Facility
International Nuclear Information System (INIS)
Morrone, A.
1975-01-01
A description is given of the analysis and results for the Fast Flux Test Facility (FFTF) reactor system which was analyzed for both scram times and seismic responses such as bending moments and impact forces. The reactor system was represented with a one-dimensional nonlinear mathematical model with two degrees of freedom per node. The results give time history plots of various seismic responses and plots of scram times as a function of control rod travel distance for the most critical scram initiation times. The total scram time considering the effects of the earthquake was still acceptable but about 4 times longer than that calculated without the earthquake. (U.S.)
Seismic analysis of mechanical systems at Pickering NGS
International Nuclear Information System (INIS)
Ghobarah, A.
1995-11-01
The objective of this study is to assess the seismic withstand capacity of selected safety-related mechanical systems associated with the Pressure Relief Duct (PRD) at the Pickering A Nuclear Generating Station. These systems are attached to the PRD and include the Emergency Coolant Injection System piping, the Vacuum Ducts, the Emergency Water Storage System, the PRD expansion joint seals and the PRD to Reactor Building joint seals. The input support motion to the mechanical systems is taken to be the seismic response of the PRD determined in an earlier study using various levels of predetermined ground response spectrum envelope. (author). 12 refs., 13 tabs., 48 figs
The seismic fragility analysis for multi-story steel structure in CANDU nuclear power plant
International Nuclear Information System (INIS)
Hwang, K.H.; Lee, B.S.; Kang, S-K.
1996-01-01
The Wolsong Unit 2 is a CANDU-6 type plant and is being constructed in the Wolsong site, where Design Basis Earthquake (DBE) was determined to be 0.2g. A seismic PSA for Wolsong Unit 2 is being performed as one of the conditions for the Construction Permit. One of the issues in the seismic PSA is the availability of the seismically non-qualified systems, which are located in the Turbine Building(T/B). Thus, the seismic fragility analysis for the T/B was performed to estimate the operability of the systems. The design seismic loads for the building were based on a ground response spectrum scaled down from the DBE to horizontal peak ground acceleration (pga) of 0.05g. The seismic fragility analysis for the building was performed using a factor of the safety method. It is estimated that the most critical failure is that of masonry walls and its High Confidence and Low Probability of Failure (HCLPF) capacity is 0.13g. The critical failure mode of the structure is identified to be tensile yielding failure of grip angle, and its HCLPF capacity is 0.34g. (author)
Uncertainty Analysis and Expert Judgment in Seismic Hazard Analysis
Klügel, Jens-Uwe
2011-01-01
The large uncertainty associated with the prediction of future earthquakes is usually regarded as the main reason for increased hazard estimates which have resulted from some recent large scale probabilistic seismic hazard analysis studies (e.g. the PEGASOS study in Switzerland and the Yucca Mountain study in the USA). It is frequently overlooked that such increased hazard estimates are characteristic for a single specific method of probabilistic seismic hazard analysis (PSHA): the traditional (Cornell-McGuire) PSHA method which has found its highest level of sophistication in the SSHAC probability method. Based on a review of the SSHAC probability model and its application in the PEGASOS project, it is shown that the surprising results of recent PSHA studies can be explained to a large extent by the uncertainty model used in traditional PSHA, which deviates from the state of the art in mathematics and risk analysis. This uncertainty model, the Ang-Tang uncertainty model, mixes concepts of decision theory with probabilistic hazard assessment methods leading to an overestimation of uncertainty in comparison to empirical evidence. Although expert knowledge can be a valuable source of scientific information, its incorporation into the SSHAC probability method does not resolve the issue of inflating uncertainties in PSHA results. Other, more data driven, PSHA approaches in use in some European countries are less vulnerable to this effect. The most valuable alternative to traditional PSHA is the direct probabilistic scenario-based approach, which is closely linked with emerging neo-deterministic methods based on waveform modelling.
BNL NONLINEAR PRE TEST SEISMIC ANALYSIS FOR THE NUPEC ULTIMATE STRENGTH PIPING TEST PROGRAM
International Nuclear Information System (INIS)
DEGRASSI, G.; HOFMAYER, C.; MURPHY, C.; SUZUKI, K.; NAMITA, Y.
2003-01-01
The Nuclear Power Engineering Corporation (NUPEC) of Japan has been conducting a multi-year research program to investigate the behavior of nuclear power plant piping systems under large seismic loads. The objectives of the program are: to develop a better understanding of the elasto-plastic response and ultimate strength of nuclear piping; to ascertain the seismic safety margin of current piping design codes; and to assess new piping code allowable stress rules. Under this program, NUPEC has performed a large-scale seismic proving test of a representative nuclear power plant piping system. In support of the proving test, a series of materials tests, static and dynamic piping component tests, and seismic tests of simplified piping systems have also been performed. As part of collaborative efforts between the United States and Japan on seismic issues, the US Nuclear Regulatory Commission (USNRC) and its contractor, the Brookhaven National Laboratory (BNL), are participating in this research program by performing pre-test and post-test analyses, and by evaluating the significance of the program results with regard to safety margins. This paper describes BNL's pre-test analysis to predict the elasto-plastic response for one of NUPEC's simplified piping system seismic tests. The capability to simulate the anticipated ratcheting response of the system was of particular interest. Analyses were performed using classical bilinear and multilinear kinematic hardening models as well as a nonlinear kinematic hardening model. Comparisons of analysis results for each plasticity model against test results for a static cycling elbow component test and for a simplified piping system seismic test are presented in the paper
Analysis of Seismic Soil-Structure Interaction for a Nuclear Power Plant (HTR-10
Directory of Open Access Journals (Sweden)
Xiaoxin Wang
2017-01-01
Full Text Available The response of nuclear power plants (NPPs to seismic events is affected by soil-structure interactions (SSI. In the present paper, a finite element (FE model with transmitting boundaries is used to analyse the SSI effect on the response of NPP buildings subjected to vertically incident seismic excitation. Analysis parameters that affect the accuracy of the calculations, including the dimension of the domain and artificial boundary types, are investigated through a set of models. A numerical SSI analysis for the 10 MW High Temperature Gas Cooled Test Reactor (HTR-10 under seismic excitation was carried out using the developed model. The floor response spectra (FRS produced by the SSI analysis are compared with a fixed-base model to investigate the SSI effect on the dynamic response of the reactor building. The results show that the FRS at foundation level are reduced and those at higher floor levels are altered significantly when taking SSI into account. The peak frequencies of the FRS are reduced due to the SSI, whereas the acceleration at high floor levels is increased at a certain frequency range. The seismic response of the primary system components, however, is reduced by the analysed SSI for the HTR-10 on the current soil site.
Geomechanics-Based Stochastic Analysis of Injection- Induced Seismicity
Energy Technology Data Exchange (ETDEWEB)
Ghassemi, Ahmad [Univ. of Oklahoma, Norman, OK (United States)
2017-08-21
The production of geothermal energy from dry and low permeability reservoirs is achieved by water circulation in natural and/or man-made fractures, and is referred to as enhanced or engineered geothermal systems (EGS). Often, the permeable zones have to be created by stimulation, a process which involves fracture initiation and/or activation of discontinuities such as faults and joints due to pore pressure and the in-situ stress perturbations. The stimulation of a rock mass is often accompanied by multiple microseismic events. Micro-seismic events associated with rock failure in shear, and shear slip on new or pre-existing fracture planes and possibly their propagations. The microseismic signals contain information about the sources of energy that can be used for understanding the hydraulic fracturing process and the created reservoir properties. Detection and interpretation of microseismic events is useful for estimating the stimulated zone, created reservoir permeability and fracture growth, and geometry of the geological structures and the in-situ stress state. The process commonly is referred to as seismicity-based reservoir characterization (SBRC). Although, progress has been made by scientific & geothermal communities for quantitative and qualitative analysis of reservoir stimulation using SBRC several key questions remain unresolved in the analysis of micro-seismicity namely, variation of seismic activity with injection rate, delayed micro-seismicity, and the relation of stimulated zone to the injected volume and its rate, and the resulting reservoir permeability. In addition, the current approach to SBRC does not consider the full range of relevant poroelastic and thermoelastic phenomena and neglects the uncertainty in rock properties and in-situ stress in the data inversion process. The objective of this research and technology developments was to develop a 3D SBRC model that addresses these shortcomings by taking into account hydro
Romanian earthquakes analysis using BURAR seismic array
International Nuclear Information System (INIS)
Borleanu, Felix; Rogozea, Maria; Nica, Daniela; Popescu, Emilia; Popa, Mihaela; Radulian, Mircea
2008-01-01
Bucovina seismic array (BURAR) is a medium-aperture array, installed in 2002 in the northern part of Romania (47.61480 N latitude, 25.21680 E longitude, 1150 m altitude), as a result of the cooperation between Air Force Technical Applications Center, USA and National Institute for Earth Physics, Romania. The array consists of ten elements, located in boreholes and distributed over a 5 x 5 km 2 area; nine with short-period vertical sensors and one with a broadband three-component sensor. Since the new station has been operating the earthquake survey of Romania's territory has been significantly improved. Data recorded by BURAR during 01.01.2005 - 12.31.2005 time interval are first processed and analyzed, in order to establish the array detection capability of the local earthquakes, occurred in different Romanian seismic zones. Subsequently a spectral ratios technique was applied in order to determine the calibration relationships for magnitude, using only the information gathered by BURAR station. The spectral ratios are computed relatively to a reference event, considered as representative for each seismic zone. This method has the advantage to eliminate the path effects. The new calibration procedure is tested for the case of Vrancea intermediate-depth earthquakes and proved to be very efficient in constraining the size of these earthquakes. (authors)
Calculation of seismic response of a flexible rotor by complex modal method, 1
International Nuclear Information System (INIS)
Azuma, Takao; Saito, Shinobu
1984-01-01
In rotary machines, at the time of earthquakes, whether the rotating part and stationary part touch or whether the bearings and seals are damaged or not are problems. In order to examine these problems, it is necessary to analyze the seismic response of a rotary shaft or sometimes a casing system. But the conventional analysis methods are unsatisfactory. Accordingly, in the case of a general shaft system supported with slide bearings and on which gyro effect acts, complex modal method must be used. This calculation method is explained in detail in the book of Lancaster, however, when this method is applied to the seismic response of rotary shafts, the calculation time is considerably different according to the method of final integration. In this study, good results were obtained when the method which did not depend on numerical integration was attempted. The equation of motion and its solution, the displacement vector of a foundation, the verification of the calculation program and the example of calculating the seismic response of two coupled rotor shafts are reported. (Kako, I.)
Directory of Open Access Journals (Sweden)
Lifen Zhang
2017-03-01
Full Text Available The Three Gorges Reservoir is a good site for the further researches on reservoir induced seismicity due to decades' seismic monitoring. After the first water impounding in 2003, seismic activity becomes more frequent than that before water impoundment. In order to quantitatively study, the relationship between the water level fluctuation and earthquakes in TGR, we introduced statistical methods to attain the goal. First of all, we relocated the earthquakes in TGR region with double difference method and divided the earthquakes into 5 clusters with clustering analysis method. Secondly, to examine the impacts of water level fluctuation in different water filling stages on the seismic activity in the 5 clusters, a series of statistical analyses are applied. Pearson correlation results show that only the 175 m water level fluctuation has significantly positive impacts on the seismic activity in clusters Ⅰ, Ⅱ, Ⅲ and Ⅴ with correlation coefficients of 0.44, 0.38, 0.66 and 0.63. Cross-correlation analysis demonstrates that 0, 1, 0 and 0 month time delay separately for the clusters Ⅰ, Ⅱ, Ⅲ and Ⅴ exists. It illustrated the influences of the water loading and pore pressure diffusion on induced earthquakes. Cointegration tests and impulse response analysis denoted that the 175 m water level only had long term and significant effects just on the seismic events in the intersection region of the Fairy Mount Fault and Nine-brook Fault. One standard deviation shock to 175 m water level increased the seismic activity in cluster Ⅴ for the first 3 months, and then the negative influence was shown. After 7 months, the negative impulse response becomes stable. The long-term effect of the 175 m water impoundment also proved the important role of pore pressure diffusion in RIS with time.
Seismic analysis of ITER multi-purpose deployer
International Nuclear Information System (INIS)
Manuelraj, Manoah Stephen; Gotewal, Krishan Kumar; Dutta, Pramit; Rastogi, Naveen; Choi, Chang-Hwan; Tesini, Alessandro
2015-01-01
The Multi-Purpose Deployer (MPD) is a general purpose ITER in-vessel remote handling (RH) system. The MPD will perform various in-vessel maintenance tasks such as dust and tritium inventory control, in-service inspection, leak localization and in-vessel diagnostics maintenance. The main handling equipment, called as the MPD Transporter, consists of a series of linked bodies, which provide anchoring to the vacuum vessel port and an articulated multi-degree of freedom motion to perform the aforementioned tasks. The target payload for the MPD Transporter is 2 tons. The total length is 16.6 m and 18.1 m for short and long configuration respectively, while the total weight of the system is about 25.5 tons including the payload. During the in-vessel operations, the structural integrity of the system should be guaranteed against various operational and seismic loads. This paper presents the seismic structural analysis results of the concept design of the MPD Transporter. Static structural, modal and frequency response spectrum analyses have been performed to verify the structural integrity of the MPD itself, and to provide reaction loads to the interfacing systems such as vacuum vessel and cask. The analyses are carried out by using the ANSYS. The first analysis iteration was carried out for the reference design of the MPD Transporter, which showed stresses higher than the permissible limit. Structural optimizations and reinforcements were performed for individual bodies referring the stress levels in each body, and a reinforced design was proposed. The reinforced design satisfies the required structural criteria in terms of general global stresses. Though local stress concentrations were observed, it can be solved in the next design phase by further local reinforcements or proper material choice. (author)
Hydrodynamic response of viscous fluids under seismic excitation
International Nuclear Information System (INIS)
Ma, D.C.
1993-01-01
Hydrodynamic response of liquid-tank systems, such as reactor vessels, spent-fuel pools and liquid storage tanks have been studied extensively in the last decade (Chang et al. 1988; Ma et al. 1991). However, most of the studies are conducted with the assumption of an inviscid fluid. In recent years, the hydrodynamic response of viscous fluids has received increasing attention in high level waste storage tanks containing viscous waste material. This paper presents a numerical study on the hydrodynamic response of viscous fluids in a large 2-D fluid-tank system under seismic excitation. Hydrodynamic responses (i.e. sloshing wave height, fluid pressures, shear stress, etc.) are calculated for a fluid with various viscosities. Four fluid viscosities are considered. They are 1 cp, 120 cp, 1,000 cp and 12,000 cp (1 cp = 1.45 x 10 -7 lb-sec/in 2 ). Note that the liquid sodium of the Liquid-Metal Reactor (LMR) reactor has a viscosity of 1.38 x 10 -5 lb-sec/in 2 (about 95 cp) at an operational temperature of 900 degree F. Section 2 describes the pertinent features of the mathematical model. In Section 3, the fundamental sloshing phenomena of viscous fluid are examined. Sloshing wave height and shear stress for fluid with different viscosities are compared. The conclusions are given in Section 4
Seismic responses of N-Reactor core. Independent review of Phase II work
International Nuclear Information System (INIS)
Chen, J.C.; Lo, T.; Chinn, D.J.; Murray, R.C.; Johnson, J.J.; Maslenikov, O.R.
1985-08-01
Seismic response of the N-Reactor core was independently analyzed to validate the results of Impell's analysis. The analysis procedure consists of two major stages: linear soil-structure interaction (SSI) analysis of the overall N-Reactor structure complex and nonlinear dynamic analysis of the reactor core. In the SSI analysis, CLASSI computer codes were used to calculate the SSI response of the structures and to generate the input motions for the nonlinear reactor core analysis. In addition, the response was compared to the response from the SASSI analysis under review. The impact of foundation modeling techniques and the effect of soil stiffness variation on SSI response were also investigated. In the core analysis, a nonlinear dynamic analysis model was developed. The stiffness representation of the model was calculated through a finite element analysis of several local core geometries. Finite element analyses were also used to study the block to block interaction characteristics. Using this nonlinear dynamic model along with the basemat time histories generated from CLASSI and SASSI, several dynamic analyses of the core were performed. A series of sensitivity studies was performed to investigate the discretization of the core, the effect of vertical acceleration, the effect of basemat rocking, and modeling assumptions. In general, our independent analysis of core response validates the order of magnitude of the displacement calculated by Impell. 11 refs., 110 figs., 12 tabs
Development of seismic risk analysis methodologies at JAERI
International Nuclear Information System (INIS)
Tanaka, T.; Abe, K.; Ebisawa, K.; Oikawa, T.
1988-01-01
The usefulness of probabilistic safety assessment (PSA) is recognized worldwidely for balanced design and regulation of nuclear power plants. In Japan, the Japan Atomic Energy Research Institute (JAERI) has been engaged in developing methodologies necessary for carrying out PSA. The research and development program was started in 1980. In those days the effort was only for internal initiator PSA. In 1985 the program was expanded so as to include external event analysis. Although this expanded program is to cover various external initiators, the current effort is dedicated for seismic risk analysis. There are three levels of seismic PSA, similarly to internal initiator PSA: Level 1: Evaluation of core damage frequency, Level 2: Evaluation of radioactive release frequency and source terms, and Level 3: Evaluation of environmental consequence. In the JAERI's program, only the methodologies for level 1 seismic PSA are under development. The methodology development for seismic risk analysis is divided into two phases. The Phase I study is to establish a whole set of simple methodologies based on currently available data. In the Phase II, Sensitivity study will be carried out to identify the parameters whose uncertainty may result in lage uncertainty in seismic risk, and For such parameters, the methodology will be upgraded. Now the Phase I study has almost been completed. In this report, outlines of the study and some of its outcomes are described
Directory of Open Access Journals (Sweden)
Guo-Bo Wang
2017-01-01
Full Text Available The foundation might be separated from the supporting soil if the earthquake is big enough, which is known as base mat uplift. This paper proposed a simplified calculation model in which spring element is adopted to simulate the interaction between soil and structure. The load-deformation curve (F-D curve of the spring element can be designated to represent the base mat uplift, in which the pressure can be applied while tensile forces are not allowed. Key factors, such as seismic wave types, seismic wave excitation directions, seismic wave amplitudes, soil shear velocities, structure stiffness, and the ratio of structure height to width (H/B, were considered in the analysis. It is shown that (1 seismic wave type has significant influence on structure response due to different frequency components it contained; (2 the vertical input of seismic wave greatly affected structure response in vertical direction, while it has little impacts in horizontal direction; (3 base mat uplift is easier to take place in soil with higher shear velocity; (4 structure H/B value has complicated influence on base mat uplift. The outcome of this research is assumed to provide some references for the seismic design of the structure due to base mat uplift.
Seismic dynamic analysis of Heat Exchangers inside of the Auxiliary Buildings in AP1000TM NPP
International Nuclear Information System (INIS)
Di Fonzo, M.; Aragon, J.; Moraleda, F.; Palazuelos, M.; San Vicente, J. L.
2011-01-01
Seismic dynamic analysis was carried out for the Heat Exchangers (RNS-HR) located inside of the Auxiliary Building in AP 1000 T M NPP. The main function of the RNS-HX is to provide shutdown reactor cooling. These equipment's are safety-related. So the seismic analysis was done using the methodology for Seismic Category I (SCI) structures. The most important topic is that the RNS-HX shall withstand the effects of the Safe Shutdown Earthquake (SSE) and maintain the specified design functions. for the analysis, two finite element models (FEM) were built in order to investigate the structural response of the couple system of building and equipment. The response spectra method was used. The floor response spectra (FRS) at the slab-wall connection were used as input Lateral seismic restrain was necessary to added in order to achieve the natural frequency of 33 Hz. The global structural response was obtained by means of the modal combination method indicated in the Regulatory Guide 1.92.
Hirave, Vivek; Kalyanshetti, Mahesh
2018-02-01
Conventional fixed-base analysis ignoring the effect of soil-flexibility may result in unsafe design. Therefore, to evaluate the realistic behavior of structure the soil structure interaction (SSI) effect shall be incorporated in the analysis. In seismic analysis, provision of bracing system is one of the important option for the structure to have sufficient strength with adequate stiffness to resist lateral forces. The different configuration of these bracing systems alters the response of buildings, and therefore, it is important to evaluate the most effective bracing systems in view point of stability against SSI effect. In present study, three RC building frames, G+3, G+5 and G+7 and their respective scaled down steel model with two types of steel bracing system incorporating the effect of soil flexibility is considered for experimental and analytical study. The analytical study is carried out using Elastic continuum approach and the experimental study is carried out using Shake Table. The influence of SSI on various seismic parameters is presented. The study reveals that, steel bracing system is beneficial to control SSI effect and it is observed that V bracing is more effective, in resisting seismic load considering SSI.
Structural Identification And Seismic Analysis Of An Existing Masonry Building
International Nuclear Information System (INIS)
Del Monte, Emanuele; Galano, Luciano; Ortolani, Barbara; Vignoli, Andrea
2008-01-01
The paper presents the diagnostic investigation and the seismic analysis performed on an ancient masonry building in Florence. The building has historical interest and is subjected to conservative restrictions. The investigation involves a preliminary phase concerning the research of the historic documents and a second phase of execution of in situ and laboratory tests to detect the mechanical characteristics of the masonry. This investigation was conceived in order to obtain the 'LC2 Knowledge Level' and to perform the non-linear pushover analysis according to the new Italian Standards for seismic upgrading of existing masonry buildings
Seismic analysis of liquid metal reactor piping systems
International Nuclear Information System (INIS)
Wang, C.Y.
1987-01-01
This paper describes the finite-element numerical algorithm and its applications to LMR piping under seismic excitations. A time-history analysis technique using the implicit temporal integration scheme is addressed. A 3-D pipe element is formulated which has eight degrees of freedom per node (three displacements, three rotations, one membrane displacement, and one bending rotation) to account for the hoop, flexural, rotational, and torsional modes of the piping system. Both geometric and material nonlinearities are considered. This algorithm is unconditionally stable and is particularly suited for the seismic analysis. (orig./GL)
Nonlinear seismic analysis of a graphite reactor core
International Nuclear Information System (INIS)
Laframboise, W.L.; Desmond, T.P.
1988-01-01
Design and construction of the Department of Energy's N-Reactor located in Richland, Washington was begun in the late 1950s and completed in the early 1960s. Since then, the reactor core's structural integrity has been under review and is considered by some to be a possible safety concern. The reactor core is moderated by graphite. The safety concern stems from the degradation of the graphite due to the effects of long-term irradiation. To assess the safety of the reactor core when subjected to seismic loads, a dynamic time-history structural analysis was performed. The graphite core consists of 89 layers of numerous graphite blocks which are assembled in a 'lincoln-log' lattice. This assembly permits venting of steam in the event of a pressure tube rupture. However, such a design gives rise to a highly nonlinear structure when subjected to earthquake loads. The structural model accounted for the nonlinear interlayer sliding and for the closure and opening of gaps between the graphite blocks. The model was subjected to simulated earthquake loading, and the time-varying response of selected elements critical to safety were monitored. The analytically predicted responses (displacements and strains) were compared to allowable responses to assess margins of safety. (orig.)
Seismic Analysis for a Crane System
Energy Technology Data Exchange (ETDEWEB)
Kim, Kang Soo; Lee, Chung Young; Ryu, Jeong Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2012-05-15
The operation bridge used for an open-pool type research reactor is a crane system with a working deck for the handling of in-pool parts such as fuels, reactor components and reactor utilization facilities. The operation bridge allows operators to access the top of the reactor in the reactor pool and the fuel storage racks in the service pool. The operation bridge contains an operating platform mounted on a truck travelling on rails. Upright members are mounted on the truck to support the upper structure and two hoist monorails. The operation bridge consists of two hoists, upper girder frames, legs, cables, saddle frames, upper deck frames, lower deck frames, and the ladder. Static and dynamic analyses are performed to evaluate the structural integrity for the operation bridge for the required design loadings. The response spectrum analysis is employed as a dynamic analysis method
Seismic Analysis for a Crane System
International Nuclear Information System (INIS)
Kim, Kang Soo; Lee, Chung Young; Ryu, Jeong Soo
2012-01-01
The operation bridge used for an open-pool type research reactor is a crane system with a working deck for the handling of in-pool parts such as fuels, reactor components and reactor utilization facilities. The operation bridge allows operators to access the top of the reactor in the reactor pool and the fuel storage racks in the service pool. The operation bridge contains an operating platform mounted on a truck travelling on rails. Upright members are mounted on the truck to support the upper structure and two hoist monorails. The operation bridge consists of two hoists, upper girder frames, legs, cables, saddle frames, upper deck frames, lower deck frames, and the ladder. Static and dynamic analyses are performed to evaluate the structural integrity for the operation bridge for the required design loadings. The response spectrum analysis is employed as a dynamic analysis method
Earthquake Ground Motion Measures for Seismic Response Evaluation of Structures
Energy Technology Data Exchange (ETDEWEB)
Cho, In-Kil; Ahn, Seong-Moon; Choun, Young-Sun; Seo, Jeong-Moon
2007-03-15
This study used the assessment results of failure criteria - base shear, story drift, top acceleration and top displacement - for a PSC containment building subjected to 30 sets of near-fault ground motions to evaluate the earthquake ground motion intensity measures. Seven intensity measures, peak ground acceleration(PGA), peak ground velocity(PGV), spectral acceleration(Sa), velocity(Sv), spectrum intensity for acceleration(SIa), velocity(SIv) and displacement(SId), were used to represent alternative ground motion. The regression analyses of the failure criteria for a PSC containment building were carried out to evaluate a proper intensity measure by using two regression models and seven ground motion parameters. The regression analysis results demonstrate the correlation coefficients of the failure criteria in terms of the candidate IM. From the results, spectral acceleration(Sa) is estimated as the best parameter for a evaluation of the structural safety for a seismic PSA.
CORSSA: The Community Online Resource for Statistical Seismicity Analysis
Michael, Andrew J.; Wiemer, Stefan
2010-01-01
Statistical seismology is the application of rigorous statistical methods to earthquake science with the goal of improving our knowledge of how the earth works. Within statistical seismology there is a strong emphasis on the analysis of seismicity data in order to improve our scientific understanding of earthquakes and to improve the evaluation and testing of earthquake forecasts, earthquake early warning, and seismic hazards assessments. Given the societal importance of these applications, statistical seismology must be done well. Unfortunately, a lack of educational resources and available software tools make it difficult for students and new practitioners to learn about this discipline. The goal of the Community Online Resource for Statistical Seismicity Analysis (CORSSA) is to promote excellence in statistical seismology by providing the knowledge and resources necessary to understand and implement the best practices, so that the reader can apply these methods to their own research. This introduction describes the motivation for and vision of CORRSA. It also describes its structure and contents.
Non-linear seismic analysis of structures coupled with fluid
International Nuclear Information System (INIS)
Descleve, P.; Derom, P.; Dubois, J.
1983-01-01
This paper presents a method to calculate non-linear structure behaviour under horizontal and vertical seismic excitation, making possible the full non-linear seismic analysis of a reactor vessel. A pseudo forces method is used to introduce non linear effects and the problem is solved by superposition. Two steps are used in the method: - Linear calculation of the complete model. - Non linear analysis of thin shell elements and calculation of seismic induced pressure originating from linear and non linear effects, including permanent loads and thermal stresses. Basic aspects of the mathematical formulation are developed. It has been applied to axi-symmetric shell element using a Fourier series solution. For the fluid interaction effect, a comparison is made with a dynamic test. In an example of application, the displacement and pressure time history are given. (orig./GL)
Study on vertical seismic response model of BWR-type reactor building
International Nuclear Information System (INIS)
Konno, T.; Motohashi, S.; Izumi, M.; Iizuka, S.
1993-01-01
A study on advanced seismic design for LWR has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and Industry (MITI) of Japan. As a part of the study, it has been investigated to construct an accurate analytical model of reactor buildings for a seismic response analysis, which can reasonably represent dynamic characteristics of the building. In Japan, vibration models of reactor buildings for horizontal ground motion have been studied and examined through many simulation analyses for forced vibration tests and earthquake observations of actual buildings. And now it is possible to establish a reliable horizontal vibration model on the basis of multi-lumped mass and spring model. However, vertical vibration models have not been so much studied as horizontal models, due to less observed data for vertical motions. In this paper, the vertical seismic response models of a BWR-type reactor building including soil-structure interaction effect are numerically studied, by comparing the dynamic characteristics of (1) three dimensional finite element model, (2) multi-stick lumped mass model with a flexible base-mat, (3) multi-stick lumped mass model with a rigid base-mat and (4) single-stick lumped mass model. In particular, the BWR-type reactor building has the long span truss roof which is considered to be one of the critical members to vertical excitation. The modelings of the roof trusses are also studied
Seismic Response of 3D Steel Buildings considering the Effect of PR Connections and Gravity Frames
Directory of Open Access Journals (Sweden)
Alfredo Reyes-Salazar
2014-01-01
Full Text Available The nonlinear seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF and interior gravity frames (IGF are studied explicitly considering the contribution of the IGF. The effect on the structural response of the stiffness of the beam-to-column connections of the IGF, which is usually neglected, is also studied. It is commonly believed that the flexibility of shear connections is negligible and that 2D models can be used to properly represent 3D real structures. The results of the study indicate, however, that the moments developed on columns of IGF can be considerable and that modeling buildings as plane frames may result in very conservative designs. The contribution of IGF to the lateral structural resistance may be significant. The contribution increases when their connections are assumed to be partially restrained (PR. The incremented participation of IGF when the stiffness of their connections is considered helps to counteract the no conservative effect that results in practice when lateral seismic loads are not considered in IGF while designing steel buildings with PMRF. Thus, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis and the IGF and the stiffness of their connections should be considered as part of the lateral resistance system.
Seismic Response of 3D Steel Buildings considering the Effect of PR Connections and Gravity Frames
Haldar, Achintya; López-Barraza, Arturo; Rivera-Salas, J. Luz
2014-01-01
The nonlinear seismic responses of 3D steel buildings with perimeter moment resisting frames (PMRF) and interior gravity frames (IGF) are studied explicitly considering the contribution of the IGF. The effect on the structural response of the stiffness of the beam-to-column connections of the IGF, which is usually neglected, is also studied. It is commonly believed that the flexibility of shear connections is negligible and that 2D models can be used to properly represent 3D real structures. The results of the study indicate, however, that the moments developed on columns of IGF can be considerable and that modeling buildings as plane frames may result in very conservative designs. The contribution of IGF to the lateral structural resistance may be significant. The contribution increases when their connections are assumed to be partially restrained (PR). The incremented participation of IGF when the stiffness of their connections is considered helps to counteract the no conservative effect that results in practice when lateral seismic loads are not considered in IGF while designing steel buildings with PMRF. Thus, if the structural system under consideration is used, the three-dimensional model should be used in seismic analysis and the IGF and the stiffness of their connections should be considered as part of the lateral resistance system. PMID:24995357
Bedload transport from spectral analysis of seismic noise near rivers
Hsu, L.; Finnegan, N. J.; Brodsky, E. E.
2010-12-01
Channel change in rivers is driven by bedload sediment transport. However, the nonlinear nature of sediment transport combined with the difficulty of making direct observations in rivers at flood hinder prediction of the timing and magnitude of bedload movement. Recent studies have shown that spectral analysis of seismic noise from seismometers near rivers illustrate a correlation between the relative amplitude of high frequency (>1 Hz) seismic noise and conditions for bedload transport, presumably from the energy transferred from clast collisions with the channel. However, a previous study in the Himalayas did not contain extensive bedload transport or discharge measurements, and the correspondence of seismic noise with proxy variables such as regional hydrologic and meteorologic data was not exact. A more complete understanding of the relationship between bedload transport and seismic noise would be valuable for extending the spatial and temporal extent of bedload data. To explore the direct relationship between bedload transport and seismic noise, we examine data from several seismic stations near the Trinity River in California, where the fluvial morphodynamics and bedload rating curves have been studied extensively. We compare the relative amplitude of the ambient seismic noise with records of water discharge and sediment transport. We also examine the noise at hourly, daily, and seasonal timescales to determine other possible sources of noise. We report the influence of variables such as local river slope, adjacent geology, anthropogenic noise, and distance from the river. The results illustrate the feasibility of using existing seismic arrays to sense radiated energy from processes of bedload transport. In addition, the results can be used to design future seismic array campaigns to optimize information about bedload transport. This technique provides great spatial and temporal coverage, and can be performed where direct bedload measurements are difficult or
Seismic analysis of long tunnels: A review of simplified and unified methods
Directory of Open Access Journals (Sweden)
Haitao Yu
2017-06-01
Full Text Available Seismic analysis of long tunnels is important for safety evaluation of the tunnel structure during earthquakes. Simplified models of long tunnels are commonly adopted in seismic design by practitioners, in which the tunnel is usually assumed as a beam supported by the ground. These models can be conveniently used to obtain the overall response of the tunnel structure subjected to seismic loading. However, simplified methods are limited due to the assumptions that need to be made to reach the solution, e.g. shield tunnels are assembled with segments and bolts to form a lining ring and such structural details may not be included in the simplified model. In most cases, the design will require a numerical method that does not have the shortcomings of the analytical solutions, as it can consider the structural details, non-linear behavior, etc. Furthermore, long tunnels have significant length and pass through different strata. All of these would require large-scale seismic analysis of long tunnels with three-dimensional models, which is difficult due to the lack of available computing power. This paper introduces two types of methods for seismic analysis of long tunnels, namely simplified and unified methods. Several models, including the mass-spring-beam model, and the beam-spring model and its analytical solution are presented as examples of the simplified method. The unified method is based on a multiscale framework for long tunnels, with coarse and refined finite element meshes, or with the discrete element method and the finite difference method to compute the overall seismic response of the tunnel while including detailed dynamic response at positions of potential damage or of interest. A bridging scale term is introduced in the framework so that compatibility of dynamic behavior between the macro- and meso-scale subdomains is enforced. Examples are presented to demonstrate the applicability of the simplified and the unified methods.
Fragility analysis of a seismically-isolated emergency diesel generator
International Nuclear Information System (INIS)
Choun, Young Sun; Choi, In Kil; Ohtori, Yasuki
2005-01-01
The seismic capacity of an Emergency Diesel Generator (EDG) in nuclear power plants influences the seismic safety of the plants significantly. A recent study showed that the increase of the seismic capacity of the EDG could reduce the core damage frequency (CDF) remarkably. It is known that the major failure mode of the EDG is a concrete coning failure due to the pulling out of the anchor bolts. The use of base isolators instead of anchor bolts can increase the seismic capacity of the EDG without any major problems. The fragility curves for a base-isolated EDG should be different from those for a conventional type because the major failure mode of the base-isolated EDG will not be a concrete coning one any more. The governing failure mode of the base-isolated EDG must be the damage of the isolators. This study introduces a fragility evaluation method for an isolated EDG, and evaluates the fragilities for the isolated EDG and compares them with those for the conventional one. Evaluation of the ground motion index is also carried out to determine the governing parameter suitable for representing the seismic responses of the base isolator
Seismic Response of Low-Rise Masonry Buildings With Flexible Roof Diaphragms
National Research Council Canada - National Science Library
Cohen, Gregory
2001-01-01
This study compares the responses from shaking-table testing and analytical predictions evaluated in the context of geometric scaling, to provide a coherent description of the seismic response of low...
Seismic Responses of an Added-Story Frame Structure with Viscous Dampers
Directory of Open Access Journals (Sweden)
Xuansheng Cheng
2014-01-01
Full Text Available The damping ratio of an added-story frame structure is established based on complex damping theory to determine the structure seismic response. The viscous dampers are selected and arranged through target function method. A significant damping effect is obtained when a small velocity index is selected. The seismic responses of a five-floor reinforced concrete frame structure with directly added light steel layers and light steel layers with viscous dampers are compared with the finite element software SAP2000. Calculation results show that, after adding the layers, the structure becomes flexible and the shear in the bottom layer decreases. However, the interlaminar shear of the other layers increases. The seismic response of the added layers is very significant and exhibits obvious whiplash effect. The interstory displacement angles of some layers do not meet the requirements. The seismic response of the structure decreases after the adoption of viscous dampers; thereby seismic requirements are satisfied.
Seismic Canvas: Evolution as a Data Exploration and Analysis Tool
Kroeger, G. C.
2015-12-01
SeismicCanvas, originally developed as a prototype interactive waveform display and printing application for educational use has evolved to include significant data exploration and analysis functionality. The most recent version supports data import from a variety of standard file formats including SAC and mini-SEED, as well as search and download capabilities via IRIS/FDSN Web Services. Data processing tools now include removal of means and trends, interactive windowing, filtering, smoothing, tapering, resampling. Waveforms can be displayed in a free-form canvas or as a record section based on angular or great circle distance, azimuth or back azimuth. Integrated tau-p code allows the calculation and display of theoretical phase arrivals from a variety of radial Earth models. Waveforms can be aligned by absolute time, event time, picked or theoretical arrival times and can be stacked after alignment. Interactive measurements include means, amplitudes, time delays, ray parameters and apparent velocities. Interactive picking of an arbitrary list of seismic phases is supported. Bode plots of amplitude and phase spectra and spectrograms can be created from multiple seismograms or selected windows of seismograms. Direct printing is implemented on all supported platforms along with output of high-resolution pdf files. With these added capabilities, the application is now being used as a data exploration tool for research. Coded in C++ and using the cross-platform Qt framework, the most recent version is available as a 64-bit application for Windows 7-10, Mac OS X 10.6-10.11, and most distributions of Linux, and a 32-bit version for Windows XP and 7. With the latest improvements and refactoring of trace display classes, the 64-bit versions have been tested with over 250 million samples and remain responsive in interactive operations. The source code is available under a LPGLv3 license and both source and executables are available through the IRIS SeisCode repository.
Panou, Areti; Paulssen, Hanneke; Hatzidimitriou, Panagiotis
2015-01-01
In this study we present phase velocity maps that were obtained from the cross-correlation analysis of ambient seismic noise recorded in the region of Greece.We used one year (2013) of ambient seismic data obtained from the vertical component of 64 broadband permanent seismological stations that are
Seismic responses of an unanchored generic fixture with different simulated boundary conditions
International Nuclear Information System (INIS)
Wu, T.S.; Blomquist, C.A.; Herceg, J.E.
1994-01-01
In the design of equipment for seismic loadings, it is common to anchor the equipment to prevent tipping or sliding. However, there are situations where the equipment should not be anchored. An unanchored piece of equipment is held to the floor only by the gravitational effect and, in the absence of friction, it could move freely. In the analytical investigation of an unanchored item during a seismic event, there is uncertainty on the proper simulation of the boundary conditions so that the analysis model will have no rigid-body motion. Seismic responses of a simple analytical model that is representative of a group of unanchored equipment have been investigated with different sets of simulated boundary conditions. The results show that, when the main interest of investigation is to assess the potential for tipping during an earthquake, the case with one of the four supporting pads simply supported, its two neighboring pads constrained against twisting motion, and all pads without vertical displacements yields the most conservative prediction. The analysis is applied to the fuel processing cell of the Integral Fast Reactor project. In order not to breach the liner of the existing facility and to keep operational flexibility of the fixtures, all new equipment to be installed within the fuel processing cell are required to be unanchored
CARES (Computer Analysis for Rapid Evaluation of Structures) Version 1.0, seismic module
International Nuclear Information System (INIS)
Xu, J.; Philippacopoulas, A.J.; Miller, C.A.; Costantino, C.J.
1990-07-01
During FY's 1988 and 1989, Brookhaven National Laboratory (BNL) developed the CARES system (Computer Analysis for Rapid Evaluation of Structures) for the US Nuclear Regulatory Commission (NRC). CARES is a PC software system which has been designed to perform structural response computations similar to those encountered in licensing reviews of nuclear power plant structures. The documentation of the Seismic Module of CARES consists of three volumes. This report is Volume 2 of the three volume documentation of the Seismic Module of CARES and represents the User's Manual. 14 refs
CARES (Computer Analysis for Rapid Evaluation of Structures) Version 1.0, seismic module
International Nuclear Information System (INIS)
Xu, J.; Philippacopoulas, A.J.; Miller, C.A.; Costantino, C.J.
1990-07-01
During FY's 1988 and 1989, Brookhaven National Laboratory (BNL) developed the CARES system (Computer Analysis for Rapid Evaluation of Structures) for the US Nuclear Regulatory Commission (NRC). CARES is a PC software system which has been designed to perform structural response computations similar to those encountered in licensing reviews of nuclear power plant structures. The documentation of the Seismic Module of CARES consists of three volumes. This report represents Volume 3 of the volume documentation of the Seismic Module of CARES. It presents three sample problems typically encountered in the Soil-Structure Interaction analyses. 14 refs., 36 figs., 2 tabs
CARES (Computer Analysis for Rapid Evaluation of Structures) Version 1.0, seismic module
International Nuclear Information System (INIS)
Xu, J.; Philippacopoulas, A.J.; Miller, C.A.; Costantino, C.J.
1990-07-01
During FY's 1988 and 1989, Brookhaven National Laboratory (BNL) developed the CARES system (Computer Analysis for Rapid Evaluation of Structures) for the US Nuclear Regulatory Commission (NRC). CARES is a PC software system which has been designed to perform structural response computations similar to those encountered in licencing reviews of nuclear power plant structures. The docomentation of the Seismic Module of CARES consists of three volumes. This report represents Volume 1 of the three volume documentation of the Seismic Module of CARES. It concentrates on the theoretical basis of the system and presents modeling assumptions and limitations as well as solution schemes and algorithms of CARES. 31 refs., 6 figs
Comparative study for methods to determine the seismic response of NPP structures
International Nuclear Information System (INIS)
Varpasuo, P.
1995-01-01
There are many different important problem areas in evaluating the seismic response of structures. In this study the effort is concentrated on three of these areas. The first task is the mathematical formulation of earthquake excitation. The random vibration theory is taken as the tool in this task. The second area of interest in this study is the soil-structure interaction analysis. The approach of impedance functions is chosen and the focal point of interest is the significance of frequency dependent impedance functions. The third area of interest is the methods to determine the structural response. The following three methods were tested: the mode superposition time history method; the complex frequency response method; the response spectrum method. The comparison was made with the aid of MSC/NASTRAN code. The three methods gave for outer containment building response results which were in good agreement with each other. (author). 4 refs., 5 figs
Seismic hazard analysis of the NPP Kozloduy site
International Nuclear Information System (INIS)
Petrovski, D.; Stamatovska, S.; Arsovski, M.; Hadzievski, D.; Sokerova, D.; Solakov, D.; Vaptzarov, I.; Satchanski, S.
1993-01-01
The principal objective of this study is to define the seismic hazard for the NPP Kozloduy site. Seismic hazard is by rule defined by the probability distribution function of the peak value of the chosen ground motion parameter in a defined time interval. The overall study methodology consists of reviewing the existing geological, seismological and tectonic information to formulate this information into a mathematical model of seismic activity of the region and using this assess earthquake ground motion in terms of probability. Detailed regional and local seismological investigations have been performed. Regional investigations encompass the area within a radius of 320 km from the NPP Kozloduy site. The results of these investigations include all seismological parameters that are necessary for determination of the mathematical model of the seismicity of the region needed for the seismic hazard analysis. Regional geological and neotectonic investigations were also performed for the wider area including almost the whole territory of Bulgaria, a large part of Serbia, part of Macedonia and almost the whole south part of Romania
Design of the Caltrans Seismic Response Modification Device (SRMD) test facility
International Nuclear Information System (INIS)
Benzoni, G.; Seible, F.
1998-01-01
In the Seismic retrofit design of California's Toll Bridges, seismic isolation is used in several bridges to limit the seismic force input into the superstructure and to avoid costly superstructure retrofit measures which would require partial lane closures and traffic interruptions. Isolation bearings and dampers of the size required for these large span bridges have not been built or tested to date. This paper describes the design and construction of a full scale testing facility which will allow the real-time 6-DOF dynamic characterization of the seismic response modification devices designed for California's Toll Bridges. (author)
Probabilistic seismic hazard analysis - lessons learned: A regulator's perspective
International Nuclear Information System (INIS)
Reiter, L.
1990-01-01
Probabilistic seismic hazard analysis is a powerful, rational and attractive tool for decision-making. It is capable of absorbing and integrating a wide range of information and judgement and their associated uncertainties into a flexible framework that permits the application of societal goals and priorities. Unfortunately, its highly integrative nature can obscure those elements which drive the results, its highly quantitative nature can lead to false impressions of accuracy, and its open embrace of uncertainty can make decision-making difficult. Addressing these problems can only help to increase its use and make it more palatable to those who need to assess seismic hazard and utilize the results. (orig.)
Seismic analysis of the mirror fusion test facility shielding vault
International Nuclear Information System (INIS)
Gabrielsen, B.L.; Tsai, K.
1981-04-01
This report presents a seismic analysis of the vault in Building 431 at Lawrence Livermore National Laboratory which houses the mirror Fusion Test Facility. The shielding vault structure is approximately 120 ft long by 80 ft wide and is constructed of concrete blocks approximately 7 x 7 x 7 ft. The north and south walls are approximately 53 ft high and the east wall is approximately 29 ft high. These walls are supported on a monolithic concrete foundation that surrounds a 21-ft deep open pit. Since the 53-ft walls appeared to present the greatest seismic problem they were the first investigated
Anisotropic analysis for seismic sensitivity of groundwater monitoring wells
Pan, Y.; Hsu, K.
2011-12-01
Taiwan is located at the boundaries of Eurasian Plate and the Philippine Sea Plate. The movement of plate causes crustal uplift and lateral deformation to lead frequent earthquakes in the vicinity of Taiwan. The change of groundwater level trigged by earthquake has been observed and studied in Taiwan for many years. The change of groundwater may appear in oscillation and step changes. The former is caused by seismic waves. The latter is caused by the volumetric strain and reflects the strain status. Since the setting of groundwater monitoring well is easier and cheaper than the setting of strain gauge, the groundwater measurement may be used as a indication of stress. This research proposes the concept of seismic sensitivity of groundwater monitoring well and apply to DonHer station in Taiwan. Geostatistical method is used to analysis the anisotropy of seismic sensitivity. GIS is used to map the sensitive area of the existing groundwater monitoring well.
Reduction of uncertainties in probabilistic seismic hazard analysis
Energy Technology Data Exchange (ETDEWEB)
Seo, Jeong Moon; Choun, Young Sun; Choi, In Kil [Korea Atomic Energy Research Institute, Taejon (Korea)
1999-02-01
An integrated research for the reduction of conservatism and uncertainties in PSHA in Korea was performed. The research consisted of five technical task areas as follows; Task 1: Earthquake Catalog Development for PSHA. Task 2: Evaluation of Seismicity and Tectonics of the Korea Region. Task 3: Development of a Ground Motion Relationships. Task 4: Improvement of PSHA Modelling Methodology. Task 5: Development of Seismic Source Interpretations for the region of Korea for Inputs to PSHA. A series of tests on an ancient wooden house and an analysis on medium size earthquake in Korea were performed intensively. Signification improvement, especially in the estimation of historical earthquake, ground motion attenuation, and seismic source interpretations, were made through this study. 314 refs., 180 figs., 54 tabs. (Author)
International Nuclear Information System (INIS)
2016-07-01
The objective of this publication is to provide the state-of-the-art practice and detailed technical elements related to ground motion evaluation by ground motion prediction equations (GMPEs) and site response in the context of seismic hazard assessments as recommended in IAEA Safety Standards Series No. SSG-9, Seismic Hazards in Site Evaluation for Nuclear Installations. The publication includes the basics of GMPEs, ground motion simulation, selection and adjustment of GMPEs, site characterization, and modelling of site response in order to improve seismic hazard assessment. The text aims at delineating the most important aspects of these topics (including current practices, criticalities and open problems) within a coherent framework. In particular, attention has been devoted to filling conceptual gaps. It is written as a reference text for trained users who are responsible for planning preparatory seismic hazard analyses for siting of all nuclear installations and/or providing constraints for anti-seismic design and retrofitting of existing structures
Seismic risk analysis for the Westinghouse Electric facility, Cheswick, Pennsylvania
International Nuclear Information System (INIS)
1977-01-01
This report presents the results of a detailed seismic risk analysis of the Westinghouse Electric plutonium fuel development facility at Cheswick, Pennsylvania. This report focuses on earthquakes. The historical seismic record was established after a review of available literature, consultation with operators of local seismic arrays and examination of appropriate seismic data bases. Because of the aseismicity of the region around the site, an analysis different from the conventional closest approach in a tectonic province was adapted. Earthquakes as far from the site as 1,000 km were included, as were the possibility of earthquakes at the site. In addition, various uncertainties in the input were explicitly considered in the analysis. For example, allowance was made for both the uncertainty in predicting maximum possible earthquakes in the region and the effect of the dispersion of data about the best fit attenuation relation. The attenuation relationship is derived from two of the most recent, advanced studies relating earthquake intensity reports and acceleration. Results of the risk analysis, which include a Bayesian estimate of the uncertainties, are presented as return period accelerations. The best estimate curve indicates that the Westinghouse facility will experience 0.05 g every 220 years and 0.10 g every 1400 years. The accelerations are very insensitive to the details of the source region geometries or the historical earthquake statistics in each region and each of the source regions contributes almost equally to the cumulative risk at the site
Esposito, G.; Courage, W.
2003-01-01
This paper presents the results of a feasibility study of a seismic isolated 120.000 m^{3} LNG tank. A simple model was used to evaluate the seismic response of the isolated tank under Safe Shutdown Earthquake conditions. The frequency dependent dynamic stiffness of the foundation was
Seismic analysis of a large pool-type LMR [liquid metal reactor
International Nuclear Information System (INIS)
Wang, C.Y.; Gvildys, J.
1989-01-01
This paper describes the seismic study of a 450-MWe liquid metal reactor (LMR) under 0.3-g SSE ground excitation. Two calculations were performed using the new design configuration. They deal with the seismic response of the reactor vessel, the guard vessel and support skirt, respectively. In both calculations, the stress and displacement fields at important locations of those components are investigated. Assessments are also made on the elastic and inelastic structural capabilities for other beyond-design basis seismic loads. Results of the reactor vessel analysis reveal that the maximum equivalent stress is only about half of the material yield stress. For the guard vessel and support skirt, the stress level is very small. Regarding the analysis if inelastic structural capability, solutions of the Newmark-Hall ductility modification method show that the reactor vessel can withstand seismics with ground ZPAs ranging from 1.015 to 1.31 g, which corresponds to 3.37 to 4.37 times the basic 0.3-g SSE. Thus, the reactor vessel and guard vessel are strong enough to resist seismic loads. 4 refs., 10 figs., 5 tabs
Performances of the UNDERground SEISmic array for the analysis of seismicity in Central Italy
Directory of Open Access Journals (Sweden)
R. Scarpa
2006-06-01
Full Text Available This paper presents the first results from the operation of a dense seismic array deployed in the underground Physics Laboratories at Gran Sasso (Central Italy. The array consists of 13 short-period, three-component seismometers with an aperture of about 550 m and average sensor spacing of 90 m. The reduced sensor spacing, joined to the spatially-white character of the background noise allows for quick and reliable detection of coherent wavefront arrivals even under very poor SNR conditions. We apply high-resolution frequency-slowness and polarization analyses to a set of 27 earthquakes recorded between November, 2002, and September, 2003, at epicentral distances spanning the 20-140 km interval. We locate these events using inversion of P- and S-wave backazimuths and S-P delay times, and compare the results with data from the Centralized National Seismic Network catalog. For the case of S-wave, the discrepancies among the two set of locations never exceed 10 km; the largest errors are instead observed for the case of P-waves. This observation may be due to the fact that the small array aperture does not allow for robust assessment of waves propagating at high apparent velocities. This information is discussed with special reference to the directions of future studies aimed at elucidating the location of seismogenetic structures in Central Italy from extended analysis of the micro-seismicity.
Seismic and dynamic qualification methods
International Nuclear Information System (INIS)
Lin, C.W.
1985-01-01
This book presents the papers given at a conference on seismic effects on nuclear power plants. Topics considered at the conference included seismic qualification of equipment, multifrequency test methodologies, damping in piping systems, the amplification factor, thermal insulation, welded joints, and response factors for seismic risk analysis of piping
Rethinking ASME III seismic analysis for piping operability evaluations
International Nuclear Information System (INIS)
Adams, T.M.; Stevenson, J.D.
1994-01-01
It has been recognized since the mid 1980's that there are very large seismic margins to failure for nuclear piping systems when designed using current industry practice, design criteria, and methods. As a result of this realization there are or have been approximately eighteen initiatives within the ASME , Boiler and Pressure Vessel Code Section III, Division 1, in the form of proposed code cases and proposed code text changes designed to reduce these failure margins to more realistic values. For the most part these initiatives have concentrated on reclassifying seismic inertia stresses in the piping as secondary and increasing the allowable stress limits permitted by Section III of the ASME, Boiler Code. This paper focuses on the application of non-linear spectral analysis methods as a method to reduce the input seismic demand determination and thereby reduce the seismic failure margins. The approach is evaluated using the ASME Boiler Pressure Vessel Code Section III Subgroup on Design benchmark procedure as proposed by the Subgroup's Special Task Group on Integrated Piping Criteria. Using this procedure, criteria are compared to current code criterion and analysis methods, and several other of the currently proposed Boiler and Pressure Vessel, Section III, changes. Finally, the applicability of the non-linear spectral analysis to continued Safe Operation Evaluations is reviewed and discussed
Seismic response of the EBR-II to the Mt. Borah earthquake
International Nuclear Information System (INIS)
Gale, J.G.; Lehto, W.K.
1985-01-01
On October 28, 1983, an earthquake of magnitude 7.3 occurred in the mountains of central Idaho at a distance of 114-km from the ANL-West site. The earthquake tripped the seismic sensors in the EBR-II reactor shutdown system causing a reactor scram. Visual and operability checks of structures, components, and systems showed no indication of damage or system abnormalities and reactor restart was initiated. As a result of the earthquake, questions arose as to the magnitude of the actual stress levels in critical components and what value of ground acceleration could be experienced without damage to reactor structures. EBR-II was designed prior to implementation of present day requirements for seismic qualification and appropriate analyses had not been conducted. A lumped-mass, finite element model of the primary tank, support structure, and the reactor was generated and analyzed using the response spectrum technique. The analysis showed that the stress levels in the primary tank system were very low during the Mount Borah earthquake and that the system could experience seismic loadings three to four times those of the Mount Borah earthquake without exceeding yield stresses in any of the components
The study of elastio-plastic seismic analysis for rigid-frame structures
陳, 珉; 青木, 徹彦
2000-01-01
Elastic and elastio-plastic earthquake-resistant analysis of frame construction is mainly studied in this paper. In elastic stage, response and vibrated characteristics of symmetrical and unsymmetrical structure are investigated by comparing the results of plane and space analysis. The effect of approaching angle of seismic wave to vibrated characteristics of structure under different column/beam rate are discussed. In elastio-plastic stage, four kinds of plastic mode with different plastic p...
Seismic analysis of structures of nuclear power plants by Lanczos mode superposition method
International Nuclear Information System (INIS)
Coutinho, A.L.G.A.; Alves, J.L.D.; Landau, L.; Lima, E.C.P. de; Ebecken, N.F.F.
1986-01-01
The Lanczos Mode Superposition Method is applied in the seismic analysis of nuclear power plants. The coordinate transformation matrix is generated by the Lanczos algorithm. It is shown that, through a convenient choice of the starting vector of the algorithm, modes with participation factors are automatically selected. It is performed the Response Spectra analysis of a typical reactor building. The obtained results are compared with those determined by the classical aproach stressing the remarkable computer effectiveness of the proposed methodology. (Author) [pt
Performance-based seismic assessment of vulnerability of dam using time history analysis
Directory of Open Access Journals (Sweden)
Elmrabet Oumnia
2018-01-01
Full Text Available The current performance-based seismic assessment procedure can be computationally intensive as it requires many time history analyses (THA each requiring time intensive post-processing of results. Time history analysis is a part of structural analysis and is the calculation of the response of a structure to any earthquake. It is one of the main processes of structural design in regions where earthquakes are prevalent. The objective of this study is to evaluate the seismic performance of embankment dam located on the Oued RHISS in the Province of AL HOCEIMA using the THA method. To monitor structural behavior, the seismic vulnerability of structure is evaluated under real earthquake records with considering the soil-structure-fluide interaction. In this study, a simple assistant program is developed for implementing earthquake analyses of structure with ANSYS, ground acceleration–time history data are used for seismic analysis and dynamic numerical simulations were conducted to study and identify the total response of the soil-structure system.
Directory of Open Access Journals (Sweden)
Leng Fei
2008-09-01
Full Text Available This paper discusses the seismic analysis of concrete dams with consideration of material nonlinearity. Based on a consistent rate-dependent model and two thermodynamics-based models, two thermodynamics-based rate-dependent constitutive models were developed with consideration of the influence of the strain rate. They can describe the dynamic behavior of concrete and be applied to nonlinear seismic analysis of concrete dams taking into account the rate sensitivity of concrete. With the two models, a nonlinear analysis of the seismic response of the Koyna Gravity Dam and the Dagangshan Arch Dam was conducted. The results were compared with those of a linear elastic model and two rate-independent thermodynamics-based constitutive models, and the influences of constitutive models and strain rate on the seismic response of concrete dams were discussed. It can be concluded from the analysis that, during seismic response, the tensile stress is the control stress in the design and seismic safety evaluation of concrete dams. In different models, the plastic strain and plastic strain rate of concrete dams show a similar distribution. When the influence of the strain rate is considered, the maximum plastic strain and plastic strain rate decrease.
Frequency-dependent springs in the seismic analysis of structures
International Nuclear Information System (INIS)
Tyapin, A.G.
2005-01-01
This paper presents a two-step algorithm for the seismic analysis of structure resting on the rigid embedded basement. Frequency-domain analysis of SSI is carried out on the second step for a platform model with special 'soil spring' which is complex, frequency-dependent, wave-dependent and non-balanced. Theory is presented to obtain the parameters of the soil spring on the first step of the analysis, performed without structure (only geometry of the basement is used) using well-known SASSI code (Lysmer et al, 1981) or in some other ways. On the second step in the SASSI analysis the soil spring is included in the model as a special finite element. Thus, the first step enables to save the computer resources on structure, the second step-to save resources on soil. Soil spring is the most general form for a SSI linear analysis: conventional springs and dashpots can be easily represented in such a format. Thus, the presented approach enables to study the impact of various factors (such as the embedment depth and soil-structure separation, the off-diagonal stiffness, various formulas for stiffness and damping, etc.) on the soil spring parameters. These parameters can be studied separately from the structure itself. As an example, the study of the horizontal soil mesh size is presented. Lumped soil spring may be used on the second step to obtain structural response spectra. To get stresses complex stiffness may be distributed over the basement slab and embedded walls. The proposed approach may be considered to be the alternative to the impedance method (see ASCE4-98). (authors)
Alternative methods for the seismic analysis of piping systems
International Nuclear Information System (INIS)
Anon.
1993-01-01
This document is a review of 12 methods and criteria for the seismic analysis of piping systems. Each of the twelve chapters in this document cover the important technical aspects of a given method. The technical aspects presented are those the Subcommittee on Dynamic Stress Criteria believe important to the application of the method, and should not be considered as a positive or negative endorsement for any of the methods. There are many variables in an analysis of a piping system that can influence the selection of the analysis method and criteria to be applied. These variable include system configuration, technical issues, precedent, licensing considerations, and regulatory acceptance. They must all be considered in selecting the appropriate seismic analysis method and criteria. This is relevant for nuclear power plants
Seismic analysis of the mirror fusion test facility building
International Nuclear Information System (INIS)
Coats, D.W.
1978-01-01
This report describes a seismic analysis of the present Mirror Fusion Test Facility (MFTF) building at the Lawrence Livermore Laboratory. The analysis was conducted to evaluate how the structure would withstand the postulated design-basis earthquake (DBE). We discuss the methods of analysis used and results obtained. Also presented are a detailed description of the building, brief discussions of site geology, seismicity, and soil conditions, the approach used to postulate the DBE, and two methods for incorporating the effects of ductility. Floor spectra for the 2nd, 3rd, and 4th floors developed for preliminary equipment design are also included. The results of the analysis, based on best-estimate equipment loadings, indicate additional bracing and upgrading of connection details are required for the structure to survive the postulated design-basis earthquake. Specific recommendations are made
Influence of epicentral distance on local seismic response in Kolkata ...
Indian Academy of Sciences (India)
Corresponding author. e-mail: wkmohanty@gg.iitkgp.ernet.in. The influence of source and .... specific or site-specific contribution to the ground motion amplitudes ...... Accounting for site effects in probabilistic seismic haz- ard analyses of ...
Numerical evaluation of seismic response of shallow foundation on ...
Indian Academy of Sciences (India)
Young's modulus of concrete ν. Poisson's ratio n. Porosity φ. Friction angle. C. Cohesion ..... which may occur due to plastic flow during seismic loading. Step 3. ... foundations, free-field boundary conditions in the ..... infinite media; J. Geotech.
International Nuclear Information System (INIS)
Benda, B.J.; Johnson, J.J.; Lo, T.Y.
1981-08-01
The primary task of the Major Structure Response Project within the Seismic Safety Margins Research Program (SSMRP) was to develop detailed finite element models of the Zion Nuclear Power Plant's containment building and auxiliary-fuel-turbine (AFT) complex. The resulting models served as input to the seismic methodology analysis chain. The containment shell was modeled as a series of beam elements with the shear and bending characteristics of a circular cylindrical shell. Masses and rotary inertias were lumped at nodal points; thirteen modes were included in the analysis. The internal structure was modeled with three-dimensional finite elements, with masses again lumped at selected nodes; sixty modes were included in the analysis. The model of the AFT complex employed thin plate and shell elements to represent the concrete shear walls and floor diaphragms, and beam and truss elements to model the braced frames. Because of the size and complexity of the model, and the potentially large number of degrees of freedom, masses were lumped at a limited number of node points. These points were selected so as to minimize the effect of the discrete mass distribution on structural response. One hundred and thirteen modes were extracted. A second objective of Project IV was to investigate the effects of uncertainty and variability on structural response. To this end, four side studies were conducted. Three of them, briefly summarized in this volume, addressed themselves respectively to an investigation of sources of random variability in the dynamic response of nuclear power plant structures; formulation of a methodology for modeling and evaluating the effects of structural uncertainty on predicted modal characteristics of major nuclear power plant structures and substructures; and a preliminary evaluation of nonlinear responses in shear-wall structures. A fourth side study, reported in detail in this volume, quantified variations in dynamic characteristics and seismic
Seismic analysis of rack structures for fuel cycle facilities
International Nuclear Information System (INIS)
Mochio, Takashi; Morooka, Akihiko; Ito, Takashi.
1987-01-01
A concept of remote maintenance using in large remote cell and rack system structure, which is now under development at high active liquid waste vitrification facility of PNC and West Germany reprocessing plant WA-350, has been adopted to reduce the radiation exposure and increase the operating efficiency. The operation of a highly efficient remote maintenance system sometimes requires the rack structures to be fairly flexible, because of the large number of loose connections and/or gapped supports and the low number of rack frames. This means that there is a possibility of severe damage occurring due to large amplitude responses during a strong earthquake. Therefore, it is very important to estimate the earthquake-resistance capacity of rack structures, including process equipment, to earthquake excitation. This paper presents an outline of a new computer code ''FRACK'' to analyze the nonlinear seismic response of a rack structure developed as a first stage in the rack system seismic research program. (author)
Scaling laws for HTGR core block seismic response
International Nuclear Information System (INIS)
Dove, R.C.
1977-01-01
This paper discusses the development of scaling laws, physical modeling, and seismic testing of a model designed to represent a High Temperature Gas-Cooled Reactor (HTGR) core consisting of graphite blocks. The establishment of the proper scale relationships for length, time, force, and other parameters is emphasized. Tests to select model materials and the appropriate scales are described. Preliminary results obtained from both model and prototype systems tested under simulated seismic vibration are presented
Tool for generation of seismic floor response spectra for secondary system design
International Nuclear Information System (INIS)
Cardoso, Tarcisio F.; Almeida, Andreia A. Diniz de
2009-01-01
The spectral analysis is still a valuable method to the seismic structure design, especially when one focalizes the topics of secondary systems in large industrial installations, as nuclear power plants. Two aspects of this situation add their arguments to recommend the use of this kind of analysis: the random character of the excitation and the multiplicity and the variability of the secondary systems. The first aspect can be managed if one assumes the site seismicity represented by a power spectrum density function of the ground acceleration, and then, by the systematic resolution of a first passage problem, to develop a uniformly probable response spectrum. The second one suggests also a probabilistic approach to the response spectrum in order to be representative all over the extensive group of systems with different characteristics, which can be enrolled in a plant. The present paper proposes a computational tool to achieve in-structure floor response spectra for secondary system design, which includes a probabilistic approach and considers coupling effects between primary and inelastic secondary systems. The analysis is performed in the frequency domain, with SASSI2000 system. A set of auxiliary programs are developed to consider three-dimensional models and their responses to a generic base excitation, acting in 3 orthogonal directions. The ground excitation is transferred to a secondary system SDOF model conveniently attached to the primary system. Then, a uniformly probable coupled response spectrum is obtained using a first passage analysis. In this work, the ExeSASSI program is created to manage SASSI2000 several modules and a set of auxiliary programs created to perform the probabilistic analyses. (author)
UMTS rapid response real-time seismic networks: implementation and strategies at INGV
Govoni, Aladino; Margheriti, Lucia; Moretti, Milena; Lauciani, Valentino; Sensale, Gianpaolo; Bucci, Augusto; Criscuoli, Fabio
2015-04-01
The benefits of portable real-time seismic networks are several and well known. During the management of a temporary experiment from the real-time data it is possible to detect and fix rapidly problems with power supply, time synchronization, disk failures and, most important, seismic signal quality degradation due to unexpected noise sources or sensor alignment/tampering. This usually minimizes field maintenance trips and maximizes both the quantity and the quality of the acquired data. When the area of the temporary experiment is not well monitored by the local permanent network, the real-time data from the temporary experiment can be fed to the permanent network monitoring system improving greatly both the real-time hypocentral locations and the final revised bulletin. All these benefits apply also in case of seismic crises when rapid deployment stations can significantly contribute to the aftershock analysis. Nowadays data transmission using meshed radio networks or satellite systems is not a big technological problem for a permanent seismic network where each site is optimized for the device power consumption and is usually installed by properly specialized technicians that can configure transmission devices and align antennas. This is not usually practical for temporary networks and especially for rapid response networks where the installation time is the main concern. These difficulties are substantially lowered using the now widespread UMTS technology for data transmission. A small (but sometimes power hungry) properly configured device with an omnidirectional antenna must be added to the station assembly. All setups are usually configured before deployment and this allows for an easy installation also by untrained personnel. We describe here the implementation of a UMTS based portable seismic network for both temporary experiments and rapid response applications developed at INGV. The first field experimentation of this approach dates back to the 2009 L
A scenario-based procedure for seismic risk analysis
International Nuclear Information System (INIS)
Kluegel, J.-U.; Mualchin, L.; Panza, G.F.
2006-12-01
A new methodology for seismic risk analysis based on probabilistic interpretation of deterministic or scenario-based hazard analysis, in full compliance with the likelihood principle and therefore meeting the requirements of modern risk analysis, has been developed. The proposed methodology can easily be adjusted to deliver its output in a format required for safety analysts and civil engineers. The scenario-based approach allows the incorporation of all available information collected in a geological, seismotectonic and geotechnical database of the site of interest as well as advanced physical modelling techniques to provide a reliable and robust deterministic design basis for civil infrastructures. The robustness of this approach is of special importance for critical infrastructures. At the same time a scenario-based seismic hazard analysis allows the development of the required input for probabilistic risk assessment (PRA) as required by safety analysts and insurance companies. The scenario-based approach removes the ambiguity in the results of probabilistic seismic hazard analysis (PSHA) which relies on the projections of Gutenberg-Richter (G-R) equation. The problems in the validity of G-R projections, because of incomplete to total absence of data for making the projections, are still unresolved. Consequently, the information from G-R must not be used in decisions for design of critical structures or critical elements in a structure. The scenario-based methodology is strictly based on observable facts and data and complemented by physical modelling techniques, which can be submitted to a formalised validation process. By means of sensitivity analysis, knowledge gaps related to lack of data can be dealt with easily, due to the limited amount of scenarios to be investigated. The proposed seismic risk analysis can be used with confidence for planning, insurance and engineering applications. (author)
Two-dimensional horizontal model seismic test and analysis for HTGR core
International Nuclear Information System (INIS)
Ikushima, Takeshi; Honma, Toshiaki.
1988-05-01
The resistance against earthquakes of high-temperature gas-cooled reactor (HTGR) core with block-type fuels is not fully ascertained yet. Seismic studies must be made if such a reactor plant is to be installed in areas with frequent earthquakes. The paper presented the test results of seismic behavior of a half scale two-dimensional horizontal slice core model and analysis. The following is a summary of the more important results. (1) When the core is subjected to the single axis excitation and simultaneous two-axis excitations to the core across-corners, it has elliptical motion. The core stays lumped motion at the low excitation frequencies. (2) When the load is placed on side fixed reflector blocks from outside to the core center, the core displacement and reflector impact reaction force decrease. (3) The maximum displacement occurs at simultaneous two-axis excitations. The maximum displacement occurs at the single axis excitation to the core across-flats. (4) The results of two-dimensional horizontal slice core model was compared with the results of two-dimensional vertical one. It is clarified that the seismic response of actual core can be predicted from the results of two-dimensional vertical slice core model. (5) The maximum reflector impact reaction force for seismic waves was below 60 percent of that for sinusoidal waves. (6) Vibration behavior and impact response are in good agreement between test and analysis. (author)
Seismic analysis for safety related structures of 900MWe PWR NPP
International Nuclear Information System (INIS)
Liu Wei
2002-01-01
Nuclear Power Plant aseismic design becomes more and more important in China due to the fact that China is a country where earthquakes occur frequently and most of plants arc unavoidably located in seismic regions. Therefore, Chinese nuclear safety authority and organizations have worked out a series of regulations and codes related to NPP anti-seismic design taking account of local conditions. The author presents here an example of structural anti-seismic design of 90GM We PWR NPP which is comprised of: ground motion input, including the principles for ground motion determination and time history generation; soil and upper-structure modelling, presenting modeling procedures and typical models of safety related buildings such as Reactor Building, Nuclear Auxiliary Building and Fuel Building; soil-structure interaction analysis; and in-structure response analysis and floor response spectrum generation. With this example, the author intends to give an overview of Chinese practice in NPP structure anti-seismic design such as the main procedures to be followed and the codes and regulations to be respected. (author)
Seismic response of elastically restrained single bellows expansion joint in lateral mode
International Nuclear Information System (INIS)
Kameswara Rao, C.; Radhakrishna, M.
2003-01-01
The present paper attempts to derive an exact solution for the seismic response of U type of single bellows that are considered elastically restrained against rotation to classical fixed-fixed case considered by Morishita et al. (author)
Seismic response of bridge pier on rigid caisson foundation in soil stratum
Tsigginos, C.; Gerolymos, N.; Assimaki, D.; Gazetas, G.
2008-03-01
An analytical method to study the seismic response of a bridge pier supported on a rigid caisson foundation embedded in a deep soil stratum underlain by a homogeneous half space is developed. The method reproduces the kinematic and inertial responses, using translational and rotational distributed Winkler springs and dashpots to simulate the soil-caisson interaction. Closed-form solutions are given in the frequency domain for vertical harmonic S-wave excitation. Comparison with results from finite element (FE) analysis and other available solutions demonstrates the reliability of the model. Results from parametric studies are given for the kinematic and inertial responses. The modification of the fundamental period and damping ratio of the bridge due to soil-structure interaction is graphically illustrated.
Seismic Analysis of Concrete Dam by Using Finite Element Method
Directory of Open Access Journals (Sweden)
Rozaina Ismail
2017-01-01
Full Text Available This paper reports a brief study on linear seismic analysis of Sg. Kinta Concrete Dam. The analysis was conducted in order to determine the performance and behaviour of the dam under seismic excitation. The dam was modelled as two-dimensional and developed based on the design drawing that is obtained from Angkasa Consulting Services Sdn. Bhd. The seismic analysis of the dam is conducted using finite element analysis software package LUSAS 14.3 and the dam has been analyse as a plain stress problem with a linear consideration. A set of historic data, with E1 Centro earthquake acceleration of about 0.50g is used as an earthquake excitation. The natural frequency and mode shape up to fifth mode of the dam has been obtained from the analysis to show the differences of the stress and deformation between each mode. The maximum horizontal and vertical stress of Sg. Kinta dam was found and the distribution of them was discussed in form of contours. The deformation of the dam were also been discussed by comparing the maximum displacement for each mode shaped.
Nonlinear seismic analysis of reinforced concrete framed structures considering joint distortion
International Nuclear Information System (INIS)
Sharma, Akanshu; Reddy, G.R.; Vaze, K.K.; Eligehausen, Rolf; Hofmann, J.
2012-01-01
Seismic behavior of a reinforced concrete framed structure can be assessed with various analytical tools that may broadly be classified as linear elastic procedures and non-linear or inelastic analysis procedures. Since the reinforced concrete structures generally go in the inelastic range due to seismic loading, it can be easily said that the inelastic procedures would predict the performance of the structures in a much better and realistic way than the linear elastic procedures. However, at the same time, the inelastic procedures are computationally much more demanding. Thus, a good balance between accuracy and computational effort is often sought for. To assess the seismic behaviour of reinforced concrete framed structures, various experimental procedures can be used. Pushover tests that consist of loading the structure monotonically till failure can be conducted on large scale structures and give information about the load carrying and deformational capacity of the structure along with sequence of failure modes but only in one direction. Static cyclic tests, where inertia effects are not included give the above mentioned information for to and fro loading direction along with the information on energy consumption. Shake table tests, which are closest to the real life earthquake tests provide almost all the information required to understand the seismic behaviour but the scale of such tests are usually limited by the capacity of the shaking table facility. In this work, practically usable and sufficiently accurate models are reported to realistically model the inelastic response of the structures. A new model to consider the inelastic behaviour of the joints of poorly detailed structures is developed and presented. A practical hysteretic rule based on the extension of Pivot hysteretic model is developed for members and beam-column joints and the same is also reported. The analytical models are validated against the experimental results using pushover analysis
Comparing Seismic And Magnetic Responses To Copper Gold Deposits Under Different Cover Sequences
Directory of Open Access Journals (Sweden)
Okan Evans Onojasun
2015-08-01
Full Text Available Appropriate application of geophysical techniques is required to effectively explore through the cover sequences that will allow the discovery of deep seated orebodies within the 1-3km depth range. Whilst potential field methods that are traditionally used for Cu-Au exploration seems effective they lack the expected resolution required to detect deeper mineral deposits under 500 m cover. Seismic reflection techniques offers a distinct advantage over all other geophysical techniques because of its ability to penetrate deeper into the subsurface without losing its resolution. We present in this report modelling results from magnetic and seismic responses to Cu-Au deposits when located within 100-1000m depth range. In the case of magnetic modelling we apply upward continuation filters which calculate the potential field that would have been recorded at 100m 250m 500m and 1000 m levels by filtering away shallow anomalies from the initial data. For seismic modelling simple but realistic geological model with varying cover thicknesses 100m 250m 500m and 1000m were created and then populate these models with petrophysical data. Simulated synthetic seismic responses from the models was processed using basic processing flows to obtained depth migrated images. Results show that for shower depths 0-100m good correlation exist between the magnetic and the seismic responses. From 100-250m depth cover though we can still see some magnetic anomalies within the target zone its effectiveness decreases with depths whereas seismic responses was maintain within the depth range. From 500m to 1000m magnetic response becomes spear or fuzzy as much useful information is practically missed out. Similarly high resolution power of seismic was ably demonstrated as the depth of even 2km did not degrade its resolution. Thus both magnetic and seismic methods are very useful for shallow investigation but at greater depth seismic method appears to be a more valid exploration
Seismic Responses of an Added-Story Frame Structure with Viscous Dampers
Cheng, Xuansheng; Jia, Chuansheng; Zhang, Yue
2014-01-01
The damping ratio of an added-story frame structure is established based on complex damping theory to determine the structure seismic response. The viscous dampers are selected and arranged through target function method. A significant damping effect is obtained when a small velocity index is selected. The seismic responses of a five-floor reinforced concrete frame structure with directly added light steel layers and light steel layers with viscous dampers are compared with the finite element...
Scale model study of the seismic response of a nuclear reactor core
International Nuclear Information System (INIS)
Dove, R.C.; Dunwoody, W.E.; Rhorer, R.L.
1983-01-01
The use of scale models to study the dynamics of a system of graphite core blocks used in certain nuclear reactor designs is described. Scaling laws, material selecton, model instrumentation to measure collision forces, and the response of several models to simulated seismic excitation are covered. The effects of Coulomb friction between the blocks and the clearance gaps between the blocks on the system response to seismic excitation are emphasized
HTGR core seismic analysis using an array processor
International Nuclear Information System (INIS)
Shatoff, H.; Charman, C.M.
1983-01-01
A Floating Point Systems array processor performs nonlinear dynamic analysis of the high-temperature gas-cooled reactor (HTGR) core with significant time and cost savings. The graphite HTGR core consists of approximately 8000 blocks of various shapes which are subject to motion and impact during a seismic event. Two-dimensional computer programs (CRUNCH2D, MCOCO) can perform explicit step-by-step dynamic analyses of up to 600 blocks for time-history motions. However, use of two-dimensional codes was limited by the large cost and run times required. Three-dimensional analysis of the entire core, or even a large part of it, had been considered totally impractical. Because of the needs of the HTGR core seismic program, a Floating Point Systems array processor was used to enhance computer performance of the two-dimensional core seismic computer programs, MCOCO and CRUNCH2D. This effort began by converting the computational algorithms used in the codes to a form which takes maximum advantage of the parallel and pipeline processors offered by the architecture of the Floating Point Systems array processor. The subsequent conversion of the vectorized FORTRAN coding to the array processor required a significant programming effort to make the system work on the General Atomic (GA) UNIVAC 1100/82 host. These efforts were quite rewarding, however, since the cost of running the codes has been reduced approximately 50-fold and the time threefold. The core seismic analysis with large two-dimensional models has now become routine and extension to three-dimensional analysis is feasible. These codes simulate the one-fifth-scale full-array HTGR core model. This paper compares the analysis with the test results for sine-sweep motion
An efficient Bouc & Wen approach for seismic analysis of masonry tower
Directory of Open Access Journals (Sweden)
Luca Facchini
2014-07-01
Full Text Available The assessment of existing masonry towers under exceptional loads, such as earthquake loads, requires reliable, expedite and efficient methods of analysis. These approaches should take into account both the randomness that affects the masonry properties (in some cases also the distribution of the elastic parameters and, of course, the nonlinear behavior of masonry. Considering the need of simplified but effective methods to assess the seismic response of such structures, the paper proposes an efficient approach for seismic assessment of masonry towers assuming the material properties as a stochastic field. As a prototype of masonry towers a cantilever beam is analyzed assuming that the first modal shape governs the structural motion. With this hypothesis a nonlinear hysteretic Bouc & Wen model is employed to reproduce the system response which is subsequently employed to evaluate the response bounds. The results of the simplified approach are compared with the results of a finite element model to show the effectiveness of the method.
International Nuclear Information System (INIS)
Subramanian, K.V.; Palekar, S.M.; Bavare, M.S.; Mapari, H.A.; Patel, S.C.; Pillai, C.S.
2005-01-01
This paper provides salient features of the Soil Structure Interaction analysis of Nuclear Island Connected Building (NICB). The dynamic analysis of NICB is performed on a full 3D model accounting for the probable variation in the stiffness of the founding medium. A range analyses was performed to establish the effect of variability of subgrade parameters on the results of seismic analyses of NICB. This paper presents details of various analyses with respect to the subgrade model, uncertainties in subgrade properties, results of seismic analyses and a study of effect of the variability of parameters on the results of these analyses. The results of this study indicate that the variability of soil parameters beyond a certain value of shear wave velocity does not influence the response and in fact the response marginally diminishes. (authors)
Building the Community Online Resource for Statistical Seismicity Analysis (CORSSA)
Michael, A. J.; Wiemer, S.; Zechar, J. D.; Hardebeck, J. L.; Naylor, M.; Zhuang, J.; Steacy, S.; Corssa Executive Committee
2010-12-01
Statistical seismology is critical to the understanding of seismicity, the testing of proposed earthquake prediction and forecasting methods, and the assessment of seismic hazard. Unfortunately, despite its importance to seismology - especially to those aspects with great impact on public policy - statistical seismology is mostly ignored in the education of seismologists, and there is no central repository for the existing open-source software tools. To remedy these deficiencies, and with the broader goal to enhance the quality of statistical seismology research, we have begun building the Community Online Resource for Statistical Seismicity Analysis (CORSSA). CORSSA is a web-based educational platform that is authoritative, up-to-date, prominent, and user-friendly. We anticipate that the users of CORSSA will range from beginning graduate students to experienced researchers. More than 20 scientists from around the world met for a week in Zurich in May 2010 to kick-start the creation of CORSSA: the format and initial table of contents were defined; a governing structure was organized; and workshop participants began drafting articles. CORSSA materials are organized with respect to six themes, each containing between four and eight articles. The CORSSA web page, www.corssa.org, officially unveiled on September 6, 2010, debuts with an initial set of approximately 10 to 15 articles available online for viewing and commenting with additional articles to be added over the coming months. Each article will be peer-reviewed and will present a balanced discussion, including illustrative examples and code snippets. Topics in the initial set of articles will include: introductions to both CORSSA and statistical seismology, basic statistical tests and their role in seismology; understanding seismicity catalogs and their problems; basic techniques for modeling seismicity; and methods for testing earthquake predictability hypotheses. A special article will compare and review
CORSSA: Community Online Resource for Statistical Seismicity Analysis
Zechar, J. D.; Hardebeck, J. L.; Michael, A. J.; Naylor, M.; Steacy, S.; Wiemer, S.; Zhuang, J.
2011-12-01
Statistical seismology is critical to the understanding of seismicity, the evaluation of proposed earthquake prediction and forecasting methods, and the assessment of seismic hazard. Unfortunately, despite its importance to seismology-especially to those aspects with great impact on public policy-statistical seismology is mostly ignored in the education of seismologists, and there is no central repository for the existing open-source software tools. To remedy these deficiencies, and with the broader goal to enhance the quality of statistical seismology research, we have begun building the Community Online Resource for Statistical Seismicity Analysis (CORSSA, www.corssa.org). We anticipate that the users of CORSSA will range from beginning graduate students to experienced researchers. More than 20 scientists from around the world met for a week in Zurich in May 2010 to kick-start the creation of CORSSA: the format and initial table of contents were defined; a governing structure was organized; and workshop participants began drafting articles. CORSSA materials are organized with respect to six themes, each will contain between four and eight articles. CORSSA now includes seven articles with an additional six in draft form along with forums for discussion, a glossary, and news about upcoming meetings, special issues, and recent papers. Each article is peer-reviewed and presents a balanced discussion, including illustrative examples and code snippets. Topics in the initial set of articles include: introductions to both CORSSA and statistical seismology, basic statistical tests and their role in seismology; understanding seismicity catalogs and their problems; basic techniques for modeling seismicity; and methods for testing earthquake predictability hypotheses. We have also begun curating a collection of statistical seismology software packages.
Seismic and hydroacoustic analysis relevant to MH370
Energy Technology Data Exchange (ETDEWEB)
Stead, Richard J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2014-07-03
The vicinity of the Indian Ocean is searched for open and readily available seismic and/or hydroacoustic stations that might have recorded a possible impact of MH370 with the ocean surface. Only three stations are identified: the IMS hydrophone arrays H01 and H08, and the Geoscope seismic station AIS. Analysis of the data from these stations shows an interesting arrival on H01 that has some interference from an Antarctic ice event, large amplitude repeating signals at H08 that obscure any possible arrivals, and large amplitude chaotic noise at AIS precludes any analysis at higher frequencies of interest. The results are therefore rather inconclusive but may point to a more southerly impact location within the overall Indian Ocean search region. The results would be more useful if they can be combined with any other data that are not readily available.
Analysis of the seismic hazard to an underground waste repository
International Nuclear Information System (INIS)
Wight, L.H.
1979-01-01
Conclusions are: The consequence associated with intense vibratory shaking of a well-designed repository is essentially negligible. The specification of an appropriate seismic vibratory design criteria could best be accomplished with a Bayesian seismic hazard assessment, using geologic slip rates as input. The consequence associated with fault displacement is very site specific and dependent on the host geologic media and its permeability changes in response to fault displacement. The probability of faulting through a repository in its million year design life is rather high, principally because of a high probability of primary or secondary faulting on undetected faults. The faulting probability can be minimized by deploying sophisticated site certification programs. High resolution microseismic surveillance seems to be most appropriate. The author's judgement is that the repository simulation program can neglect consequences associated with shaking of the repository, but that the probability of significant fault displacement through the repository during its design life should be conservatively taken as one
Directory of Open Access Journals (Sweden)
Clara Monaco
2016-09-01
Full Text Available Cetaceans use sound in many contexts, such as in social interactions, as well as to forage and to react in dangerous situations. Little information exists to describe how they respond physically and behaviorally to intense and long-term noise levels. Effects on cetaceans from seismic survey activities need to be understood in order to determine detailed acoustic exposure guidelines and to apply appropriated mitigation measures. This study examines direct behavioral responses of cetaceans in the southern Mediterranean Sea during seismic surveys with large airgun arrays (volume up to 5200 ci used in the TOMO-ETNA active seismic experiment of summer 2014. Wide Angle Seismic and Multi-Channel Seismic surveys had carried out with refraction and reflection seismic methods, producing about 25,800 air-gun shots. Visual monitoring undertaken in the 26 daylights of seismic exploration adopted the protocol of the Joint Nature Conservation Committee. Data recorded were analyzed to examine effects on cetaceans. Sighting rates, distance and orientation from the airguns were compared for different volume categories of the airgun arrays. Results show that cetaceans can be disturbed by seismic survey activities, especially during particularly events. Here we propose many integrated actions to further mitigate this exposure and implications for management.
LOFT diesel generator ''A'' exhaust stack seismic analysis
International Nuclear Information System (INIS)
Blandford, R.K.
1978-01-01
A stress analysis of the LOFT Diesel Generator ''A'' Exhaust Stack was performed to determine its reaction to Safe-Shutdown Earthquake loads. The exhaust stack silencer and supporting foundation was found to be inadequate for the postulated seismic accelerations. Lateral support is required to prevent overturning of the silencer pedestal and reinforcement of the 4'' x 0.5'' silencer base straps is necessary. Basic requirements for this additional support are discussed
Network similarity and statistical analysis of earthquake seismic data
Deyasi, Krishanu; Chakraborty, Abhijit; Banerjee, Anirban
2016-01-01
We study the structural similarity of earthquake networks constructed from seismic catalogs of different geographical regions. A hierarchical clustering of underlying undirected earthquake networks is shown using Jensen-Shannon divergence in graph spectra. The directed nature of links indicates that each earthquake network is strongly connected, which motivates us to study the directed version statistically. Our statistical analysis of each earthquake region identifies the hub regions. We cal...
Seismic testing and analysis of a prototypic nonlinear piping system
International Nuclear Information System (INIS)
Barta, D.A.; Anderson, M.J.; Severud, L.K.
1982-11-01
A series of seismic tests and analyses of a nonlinear Fast Flux Test Facility (FFTF) prototypic piping system are described, and measured responses are compared with analytical predictions. The test loop was representative of a typical LMFBR insulated small bore piping system and it was supported from a rigid test frame by prototypic dead weight supports, mechanical snubbers and pipe clamps. Various piping support configurations were tested and analyzed to evaluate the effects of free play and other nonlinear stiffness characteristics on the piping system response
Farrell, M. E.; Russo, R. M.
2013-12-01
The installation of Earthscope Transportable Array-style geophysical observatories in Chile expands open data seismic recording capabilities in the southern hemisphere by nearly 30%, and has nearly tripled the number of seismic stations providing freely-available data in southern South America. Through the use of collocated seismic and atmospheric sensors at these stations we are able to analyze how local atmospheric conditions generate seismic noise, which can degrade data in seismic frequency bands at stations in the ';roaring forties' (S latitudes). Seismic vaults that are climate-controlled and insulated from the local environment are now employed throughout the world in an attempt to isolate seismometers from as many noise sources as possible. However, this is an expensive solution that is neither practical nor possible for all seismic deployments; and also, the increasing number and scope of temporary seismic deployments has resulted in the collection and archiving of terabytes of seismic data that is affected to some degree by natural seismic noise sources such as wind and atmospheric pressure changes. Changing air pressure can result in a depression and subsequent rebound of Earth's surface - which generates low frequency noise in seismic frequency bands - and even moderate winds can apply enough force to ground-coupled structures or to the surface above the seismometers themselves, resulting in significant noise. The 10 stations of the permanent Geophysical Reporting Observatories (GRO Chile), jointly installed during 2011-12 by IRIS and the Chilean Servicio Sismológico, include instrumentation in addition to the standard three seismic components. These stations, spaced approximately 300 km apart along the length of the country, continuously record a variety of atmospheric data including infrasound, air pressure, wind speed, and wind direction. The collocated seismic and atmospheric sensors at each station allow us to analyze both datasets together, to
User's manual for seismic analysis code 'SONATINA-2V'
International Nuclear Information System (INIS)
Hanawa, Satoshi; Iyoku, Tatsuo
2001-08-01
The seismic analysis code, SONATINA-2V, has been developed to analyze the behavior of the HTTR core graphite components under seismic excitation. The SONATINA-2V code is a two-dimensional computer program capable of analyzing the vertical arrangement of the HTTR graphite components, such as fuel blocks, replaceable reflector blocks, permanent reflector blocks, as well as their restraint structures. In the analytical model, each block is treated as rigid body and is restrained by dowel pins which restrict relative horizontal movement but allow vertical and rocking motions between upper and lower blocks. Moreover, the SONATINA-2V code is capable of analyzing the core vibration behavior under both simultaneous excitations of vertical and horizontal directions. The SONATINA-2V code is composed of the main program, pri-processor for making the input data to SONATINA-2V and post-processor for data processing and making the graphics from analytical results. Though the SONATINA-2V code was developed in order to work in the MSP computer system of Japan Atomic Energy Research Institute (JAERI), the computer system was abolished with the technical progress of computer. Therefore, improvement of this analysis code was carried out in order to operate the code under the UNIX machine, SR8000 computer system, of the JAERI. The users manual for seismic analysis code, SONATINA-2V, including pri- and post-processor is given in the present report. (author)
Analysis of Cylindrical Granular Material Silos under Seismic Excitation
Directory of Open Access Journals (Sweden)
Christoph Butenweg
2017-07-01
Full Text Available Silos generally work as storage structures between supply and demand for various goods, and their structural safety has long been of interest to the civil engineering profession. This is especially true for dynamically loaded silos, e.g., in case of seismic excitation. Particularly thin-walled cylindrical silos are highly vulnerable to seismic induced pressures, which can cause critical buckling phenomena of the silo shell. The analysis of silos can be carried out in two different ways. In the first, the seismic loading is modeled through statically equivalent loads acting on the shell. Alternatively, a time history analysis might be carried out, in which nonlinear phenomena due to the filling as well as the interaction between the shell and the granular material are taken into account. The paper presents a comparison of these approaches. The model used for the nonlinear time history analysis considers the granular material by means of the intergranular strain approach for hypoplasticity theory. The interaction effects between the granular material and the shell is represented by contact elements. Additionally, soil–structure interaction effects are taken into account.
International Nuclear Information System (INIS)
Joshi, J.R.
2000-01-01
The Process, Purification and Stack Buildings are collocated safety related concrete shear wall structures with plan dimensions in excess of 100 feet. An important aspect of their seismic analysis was the determination of structure soil structure interaction (SSSI) effects, if any. The SSSI analysis of the Process Building, with one other building at a time, was performed with the SASSI computer code for up to 50 frequencies. Each combined model had about 1500 interaction nodes. Results of the SSSI analysis were compared with those from soil structure interaction (SSI) analysis of the individual buildings, done with ABAQUS and SASSI codes, for three parameters: peak accelerations, seismic forces and the in-structure floor response spectra (FRS). The results may be of wider interest due to the model size and the potential applicability to other deep soil layered sites. Results obtained from the ABAQUS analysis were consistently higher, as expected, than those from the SSI and SSSI analyses using the SASSI. The SSSI effect between the Process and Purification Buildings was not significant. The Process and Stack Building results demonstrated that under certain conditions a massive structure can have an observable effect on the seismic response of a smaller and less stiff structure
Comparison of seismic isolation concepts for FBR
International Nuclear Information System (INIS)
Shiojiri, H.; Mazda, T.; Kasai, H.; Kanda, J.N.; Kubo, T.; Madokoro, M.; Shimomura, T.; Nojima, O.
1989-01-01
This paper seeks to verify the reliability and effectiveness of seismic isolation for FBR. Some results of the preliminary study of the program are described. Seismic isolation concepts and corresponding seismic isolation devices were selected. Three kinds of seismically-isolated FBR plant concepts were developed by applying promising seismic isolation concepts to the non-isolated FBR plant, and by developing plant component layout plans and building structural designs. Each plant was subjected to seismic response analysis and reduction in the amount of material of components and buildings were estimated for each seismic isolation concepts. Research and development items were evaluated
SSHAC Level 1 Probabilistic Seismic Hazard Analysis for the Idaho National Laboratory
International Nuclear Information System (INIS)
Payne, Suzette Jackson; Coppersmith, Ryan; Coppersmith, Kevin; Rodriguez-Marek, Adrian; Falero, Valentina Montaldo; Youngs, Robert
2016-01-01
A Probabilistic Seismic Hazard Analysis (PSHA) was completed for the Materials and Fuels Complex (MFC), Advanced Test Reactor (ATR), and Naval Reactors Facility (NRF) at the Idaho National Laboratory (INL). The PSHA followed the approaches and procedures for Senior Seismic Hazard Analysis Committee (SSHAC) Level 1 study and included a Participatory Peer Review Panel (PPRP) to provide the confident technical basis and mean-centered estimates of the ground motions. A new risk-informed methodology for evaluating the need for an update of an existing PSHA was developed as part of the Seismic Risk Assessment (SRA) project. To develop and implement the new methodology, the SRA project elected to perform two SSHAC Level 1 PSHAs. The first was for the Fuel Manufacturing Facility (FMF), which is classified as a Seismic Design Category (SDC) 3 nuclear facility. The second was for the ATR Complex, which has facilities classified as SDC-4. The new methodology requires defensible estimates of ground motion levels (mean and full distribution of uncertainty) for its criteria and evaluation process. The INL SSHAC Level 1 PSHA demonstrates the use of the PPRP, evaluation and integration through utilization of a small team with multiple roles and responsibilities (four team members and one specialty contractor), and the feasibility of a short duration schedule (10 months). Additionally, a SSHAC Level 1 PSHA was conducted for NRF to provide guidance on the potential use of a design margin above rock hazard levels for the Spent Fuel Handling Recapitalization Project (SFHP) process facility.
SSHAC Level 1 Probabilistic Seismic Hazard Analysis for the Idaho National Laboratory
Energy Technology Data Exchange (ETDEWEB)
Payne, Suzette Jackson [Idaho National Lab. (INL), Idaho Falls, ID (United States); Coppersmith, Ryan [Idaho National Lab. (INL), Idaho Falls, ID (United States); Coppersmith, Kevin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Rodriguez-Marek, Adrian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Falero, Valentina Montaldo [Idaho National Lab. (INL), Idaho Falls, ID (United States); Youngs, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States)
2016-09-01
A Probabilistic Seismic Hazard Analysis (PSHA) was completed for the Materials and Fuels Complex (MFC), Advanced Test Reactor (ATR), and Naval Reactors Facility (NRF) at the Idaho National Laboratory (INL). The PSHA followed the approaches and procedures for Senior Seismic Hazard Analysis Committee (SSHAC) Level 1 study and included a Participatory Peer Review Panel (PPRP) to provide the confident technical basis and mean-centered estimates of the ground motions. A new risk-informed methodology for evaluating the need for an update of an existing PSHA was developed as part of the Seismic Risk Assessment (SRA) project. To develop and implement the new methodology, the SRA project elected to perform two SSHAC Level 1 PSHAs. The first was for the Fuel Manufacturing Facility (FMF), which is classified as a Seismic Design Category (SDC) 3 nuclear facility. The second was for the ATR Complex, which has facilities classified as SDC-4. The new methodology requires defensible estimates of ground motion levels (mean and full distribution of uncertainty) for its criteria and evaluation process. The INL SSHAC Level 1 PSHA demonstrates the use of the PPRP, evaluation and integration through utilization of a small team with multiple roles and responsibilities (four team members and one specialty contractor), and the feasibility of a short duration schedule (10 months). Additionally, a SSHAC Level 1 PSHA was conducted for NRF to provide guidance on the potential use of a design margin above rock hazard levels for the Spent Fuel Handling Recapitalization Project (SFHP) process facility.
Seismicity rate surge on faults after shut-in: poroelastic response to fluid injection
Chang, K. W.; Yoon, H.; Martinez, M. J.
2017-12-01
Subsurface energy activities such as geological CO2 storage and wastewater injection require injecting large amounts of fluid into the subsurface, which will alter the states of pore pressure and stress in the storage formation. One of the main issues for injection-induced seismicity is the post shut-in increases in the seismicity rate, often observed in the fluid-injection operation sites. The rate surge can be driven by the following mechanisms: (1) pore-pressure propagation into distant faults after shut-in and (2) poroelastic stressing caused by well operations, depending on fault geometry, hydraulic and mechanical properties of the formation, and injection history. We simulate the aerial view of the target reservoir intersected by strike-slip faults, in which injection-induced pressure buildup encounters the faults directly. We examine the poroelastic response of the faults to fluid injection and perform a series of sensitivity tests considering: (1) permeability of the fault zone, (2) locations and the number of faults with respect to the injection point, and (3) well operations with varying the injection rate. Our analysis of the Coulomb stress change suggests that the sealing fault confines pressure diffusion which stabilizes or weakens the nearby conductive fault depending on the injection location. We perform the sensitivity test by changing injection scenarios (time-dependent rates), while keeping the total amount of injected fluids. Sensitivity analysis shows that gradual reduction of the injection rate minimizes the Coulomb stress change and the least seismicity rates are predicted. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.
Energy Technology Data Exchange (ETDEWEB)
MACKEY TC; DEIBLER JE; RINKER MW; JOHNSON KI; ABATT FG; KARRI NK; PILLI SP; STOOPS KL
2009-01-15
design waste temperature of 350 F and the full 60-year corrosion allowance on the tank wall of 0.060 inch. However, analysis at a more realistic temperature of 250 F or corrosion allowance of 0.025 inch results in an acceptable demand/capacity ratio according to the ASME code criteria. Thus, buckling of the primary tank is judged to be unlikely for the current lack of corrosion in the tanks, and the expectation that the maximum waste temperature will not exceed 210 F. The reinforced concrete structure was evaluated as specified by the American Concrete Institute (ACI) code requirements for nuclear safety-related structures (ACI-349). The demand was demonstrated to be lower than the capacity at all locations. Revision 1 is being issued to document changes to the anchor bolt evaluation. RPP-RPT-32237 Rev. 1, Hanford Double-Shell Tank Thermal and Seismic Project-Increased Liquid Level Analysis for 241AP Tank Farms, described changes to the anchor bolt modeling and evaluation which were implemented in response to the independent reviewer's comments. Similar changes have been made in the bounding tank analysis and are documented in RPP-RPT-28968 Rev. 1. The conclusions of the previous releases of this report remain unchanged.
Changes in water table elevation at Yucca Mountain in response to seismic events
International Nuclear Information System (INIS)
Arnold, B.W.
1996-01-01
Investigation of mechanisms which could significantly alter the elevation of the water table at Yucca Mountain are motivated by the potential impacts such an occurrence would have on the performance of a high-level radioactive waste repository. In particular, we would like to evaluate the possibility of flooding a repository by water-table excursions. Changes in the water table could occur as relatively transient phenomena in response to seismic events by the seismic pumping mechanism. Quantitative evaluation of possible fluctuations of groundwater following earthquakes was undertaken in support of performance assessment calculations including seismicity
Seismic response of reinforced concrete frames at different damage levels
Morales-González, Merangeli; Vidot-Vega, Aidcer L.
2017-03-01
Performance-based seismic engineering is focused on the definition of limit states to represent different levels of damage, which can be described by material strains, drifts, displacements or even changes in dissipating properties and stiffness of the structure. This study presents a research plan to evaluate the behavior of reinforced concrete (RC) moment resistant frames at different performance levels established by the ASCE 41-06 seismic rehabilitation code. Sixteen RC plane moment frames with different span-to-depth ratios and three 3D RC frames were analyzed to evaluate their seismic behavior at different damage levels established by the ASCE 41-06. For each span-to-depth ratio, four different beam longitudinal reinforcement steel ratios were used that varied from 0.85 to 2.5% for the 2D frames. Nonlinear time history analyses of the frames were performed using scaled ground motions. The impact of different span-to-depth and reinforcement ratios on the damage levels was evaluated. Material strains, rotations and seismic hysteretic energy changes at different damage levels were studied.
Analysis of the seismic catalogues for the Vrancea Region, Romania
International Nuclear Information System (INIS)
Romashkova, L.L.; Kossobokov, V.G.
2005-11-01
Vrancea (Romania) is a geographical region between Eastern and Southern Carpathian Mountains. The region is characterized by a rather high level of seismic activity mainly at intermediate (up to 200 km) depths. These intermediate-depth earthquakes occur between 45 deg-46 deg N and 26 deg-27 deg E. The shallow earthquakes are dispersed over a much broader territory. We performed the comparative analysis of earthquake catalogues available for Vrancea region aiming at the compilation of a data set, to be as complete and homogeneous as possible, which, hopefully, will be used for the prediction of strong and possibly moderate earthquakes in the region by means of M8 algorithm. The two catalogues under study are: 1) Global Hypocenter Data Base catalogue, NEIC (GHDB, 1989) and 2) local Vrancea seismic catalogue (Moldoveanu et al., 1995) and their updates. (author)
Armenian nuclear power plant: US NRC assistance programme for seismic upgrade and safety analysis
International Nuclear Information System (INIS)
Simos, N.; Perkins, K.; Jo, J.; Carew, J.; Ramsey, J.
2003-01-01
This paper summarizes the U.S. Nuclear Regulatory Commission's (US NRC) technical support program activities associated with the Armenian Nuclear Power Plant (ANPP) safety upgrade. The US NRC program, integrated within the overall IAEA-led initiative for safety re-evaluation of the WWER plants, has as its main thrust the technical support to the Armenian Nuclear Regulatory Authority (ANRA) through close collaboration with the scientific staff at Brookhaven National Laboratory (BNL). Several major technical areas of support to ANRA form the basis of the NRC program. These include the seismic re-evaluation and upgrade of the ANPP, safety evaluation of critical systems, and the generation of the Safety Analysis Report (SAR). Specifically, the seismic re-evaluation of the ANPP is part of a broader activity that involves the re-assessment of the seismic hazard at the site, the identification of the Safe Shutdown Equipment at the plant and the evaluation of their seismic capacity, the detailed modeling and analysis of the critical facilities at ANPP, and the generation of the Floor Response Spectra (FRS). Based on the new spectra that incorporate all new findings (hazard, site soil, structure, etc.), the overall capacity of the main structures and the seismic capacity of the critical systems are being re-evaluated. In addition, analyses of critical safe shutdown systems and safe shutdown processes are being performed to ensure both the capabilities of the operating systems and the enhancement of safety due to system upgrades. At present, one of the principal goals of the US NRC's regulatory assistance activities with ANRA is enhancing ANRA's regulatory oversight of high-priority safety issues (both generic and plant-specific) associated with operation of the ANPP. As such, assisting ANRA in understanding and assessing plant-specific seismic and other safety issues associated with the ANPP is a high priority given the ANPP's being located in a seismically active area
de Moor, A.; Trehu, A. M.; Tryon, M. D.
2015-12-01
To investigate the dynamic response of the outer accretionary wedge updip from the patch of greatest slip during the Mw8.8 2010 Maule earthquake, 10 Ocean Bottom Seismometers (OBS) were deployed from May 2012 to March 2013 in a small array with an inter-instrument spacing of ~12 km . Nine instruments were recovered, with 4 recording data on 3 intermediate-band 3-component seismometers and a differential pressure gauge and 5 recording data from absolute pressure gauges. [note: All instruments were also equipped with a fluid flow meter sensitive to flow rates as low as 0.0001 cm/yr in or out of the sediments. However, no flow signal was detected.] Here we present hypocenters for 569 local events that have S-P times less than 17 seconds (i.e. within ~125 km of the array) using hand-picked arrival times and a 1D velocity model derived from a 2D seismic refraction profile through the region (Moscoso et al 2011, EPSL). We analyze the distribution of seismicity in the context of published slip models, ChilePEPPER high-resolution seismic reflection data, critical taper analysis done by Cubas et al 2013 (EPSL), and offshore gravity data. The data show distinct segmentation within the outer prism. The northern section of the study area is characterized by a lack of seismicity, accretion of nearly all incoming sediment and a prism at critical taper. In contrast, abundant seismicity, significant sediment underthrusting at the deformation front and a prism below critical taper angle characterize the southern part of the study area. Both coseismic slip and post-rupture local seismicity can be related to density anomalies within the upper plate as revealed by free air gravity data corrected for the effects of bathymetry and the subducting plate. [ChilePEPPER - Project Evaluating Prism Post-Earthquake Response
Galiana-Merino, J. J.; Rosa-Herranz, J. L.; Rosa-Cintas, S.; Martinez-Espla, J. J.
2013-01-01
A MATLAB-based computer code has been developed for the simultaneous wavelet analysis and filtering of multichannel seismic data. The considered time-frequency transforms include the continuous wavelet transform, the discrete wavelet transform and the discrete wavelet packet transform. The developed approaches provide a fast and precise time-frequency examination of the seismograms at different frequency bands. Moreover, filtering methods for noise, transients or even baseline removal, are implemented. The primary motivation is to support seismologists with a user-friendly and fast program for the wavelet analysis, providing practical and understandable results. Program summaryProgram title: SeismicWaveTool Catalogue identifier: AENG_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AENG_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC license, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 611072 No. of bytes in distributed program, including test data, etc.: 14688355 Distribution format: tar.gz Programming language: MATLAB (MathWorks Inc.) version 7.8.0.347 (R2009a) or higher. Wavelet Toolbox is required. Computer: Developed on a MacBook Pro. Tested on Mac and PC. No computer-specific optimization was performed. Operating system: Any supporting MATLAB (MathWorks Inc.) v7.8.0.347 (R2009a) or higher. Tested on Mac OS X 10.6.8, Windows XP and Vista. Classification: 13. Nature of problem: Numerous research works have developed a great number of free or commercial wavelet based software, which provide specific solutions for the analysis of seismic data. On the other hand, standard toolboxes, packages or libraries, such as the MathWorks' Wavelet Toolbox for MATLAB, offer command line functions and interfaces for the wavelet analysis of one-component signals. Thus, software usually is focused on very specific problems
Source-Type Identification Analysis Using Regional Seismic Moment Tensors
Chiang, A.; Dreger, D. S.; Ford, S. R.; Walter, W. R.
2012-12-01
Waveform inversion to determine the seismic moment tensor is a standard approach in determining the source mechanism of natural and manmade seismicity, and may be used to identify, or discriminate different types of seismic sources. The successful applications of the regional moment tensor method at the Nevada Test Site (NTS) and the 2006 and 2009 North Korean nuclear tests (Ford et al., 2009a, 2009b, 2010) show that the method is robust and capable for source-type discrimination at regional distances. The well-separated populations of explosions, earthquakes and collapses on a Hudson et al., (1989) source-type diagram enables source-type discrimination; however the question remains whether or not the separation of events is universal in other regions, where we have limited station coverage and knowledge of Earth structure. Ford et al., (2012) have shown that combining regional waveform data and P-wave first motions removes the CLVD-isotropic tradeoff and uniquely discriminating the 2009 North Korean test as an explosion. Therefore, including additional constraints from regional and teleseismic P-wave first motions enables source-type discrimination at regions with limited station coverage. We present moment tensor analysis of earthquakes and explosions (M6) from Lop Nor and Semipalatinsk test sites for station paths crossing Kazakhstan and Western China. We also present analyses of smaller events from industrial sites. In these sparse coverage situations we combine regional long-period waveforms, and high-frequency P-wave polarity from the same stations, as well as from teleseismic arrays to constrain the source type. Discrimination capability with respect to velocity model and station coverage is examined, and additionally we investigate the velocity model dependence of vanishing free-surface traction effects on seismic moment tensor inversion of shallow sources and recovery of explosive scalar moment. Our synthetic data tests indicate that biases in scalar
Cluster Computing For Real Time Seismic Array Analysis.
Martini, M.; Giudicepietro, F.
A seismic array is an instrument composed by a dense distribution of seismic sen- sors that allow to measure the directional properties of the wavefield (slowness or wavenumber vector) radiated by a seismic source. Over the last years arrays have been widely used in different fields of seismological researches. In particular they are applied in the investigation of seismic sources on volcanoes where they can be suc- cessfully used for studying the volcanic microtremor and long period events which are critical for getting information on the volcanic systems evolution. For this reason arrays could be usefully employed for the volcanoes monitoring, however the huge amount of data produced by this type of instruments and the processing techniques which are quite time consuming limited their potentiality for this application. In order to favor a direct application of arrays techniques to continuous volcano monitoring we designed and built a small PC cluster able to near real time computing the kinematics properties of the wavefield (slowness or wavenumber vector) produced by local seis- mic source. The cluster is composed of 8 Intel Pentium-III bi-processors PC working at 550 MHz, and has 4 Gigabytes of RAM memory. It runs under Linux operating system. The developed analysis software package is based on the Multiple SIgnal Classification (MUSIC) algorithm and is written in Fortran. The message-passing part is based upon the LAM programming environment package, an open-source imple- mentation of the Message Passing Interface (MPI). The developed software system includes modules devote to receiving date by internet and graphical applications for the continuous displaying of the processing results. The system has been tested with a data set collected during a seismic experiment conducted on Etna in 1999 when two dense seismic arrays have been deployed on the northeast and the southeast flanks of this volcano. A real time continuous acquisition system has been simulated by
Cramer, C. H.; Dhar, M. S.
2017-12-01
The influence of deep sediment deposits of the Mississippi Embayment (ME) on the propagation of seismic waves is poorly understood and remains a major source of uncertainty for site response analysis. Many researchers have studied the effects of these deposits on seismic hazard of the area using available information at the time. In this study, we have used updated and newly available resources for seismic and liquefaction hazard analyses of the ME. We have developed an improved 3D geological model. Additionally, we used surface geological maps from Cupples and Van Arsdale (2013) to prepare liquefaction hazard maps. Both equivalent linear and nonlinear site response codes were used to develop site amplification distributions for use in generating hazard maps. The site amplification distributions are created using the Monte Carlo approach of Cramer et al. (2004, 2006) on a 0.1-degree grid. The 2014 National Seismic Hazard model and attenuation relations (Petersen et al., 2014) are used to prepare seismic hazard maps. Then liquefaction hazard maps are generated using liquefaction probability curves from Holzer (2011) and Cramer et al. (2015). Equivalent linear response (w/ increased precision, restricted nonlinear behavior with depth) shows similar hazard for the ME compared to nonlinear analysis (w/o pore pressure) results. At short periods nonlinear deamplification dominates the hazard, but at long periods resonance amplification dominates. The liquefaction hazard tends to be high in Holocene and late Pleistocene lowland sediments, even with lowered ground water levels, and low in Pleistocene loess of the uplands. Considering pore pressure effects in nonlinear site response analysis at a test site on the lowlands shows amplification of ground motion at short periods. PGA estimates from ME liquefaction and MMI observations are in the 0.25 to 0.4 g range. Our estimated M7.5 PGA hazard within 10 km of the fault can exceed this. Ground motion observations from
Response of a Panel Building to Mining Induced Seismicity in Karvina Area (Czech Republic)
Czech Academy of Sciences Publication Activity Database
Hradil, P.; Kaláb, Zdeněk; Knejzlík, Jaromír; Kořínek, R.; Kanický, V.
2009-01-01
Roč. 14, č. 2 (2009), s. 143-151 ISSN 1335-1788 R&D Projects: GA ČR GA105/07/0878 Institutional research plan: CEZ:AV0Z30860518 Keywords : mining seismic ity * mathematical modeling * seismic response Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.097, year: 2009 http://actamont.tuke.sk/pdf/2009/n2/2hradil.pdf
Vibration analysis and innovative technologies in the seismic preservation of cultural heritage
International Nuclear Information System (INIS)
Clemente, P.; Conti, C.; De Stefano, A.
2015-01-01
In order to preserve historical buildings and monuments against the effects of earthquakes a detailed analysis is needed to evaluate the characteristics of the seismic input and the dynamic behaviour of structures under seismic actions and to choose the most suitable seismic rehabilitation technique. In this paper the experimental analysis carried out on the Colosseum and the Lateran Obelisk are first shown. Then the application of seismic isolation in historical buildings is discussed and a new structure for the seismic isolation of existing building is presented.
Seismic response analyses of turbine hall and electrical building of RBMK-1000 MW type NPP
International Nuclear Information System (INIS)
Jordanov, M.J.; Karparov, K.T.
2003-01-01
This paper addresses results obtained during the study of turbine hall and electrical building of RBMK-1000 MW pair units at Leningradskaya NPP (LNPP) for seismic event. The study was performed in the frame of the Coordinated Research Program of the International Atomic Agency (IAEA) on Safety of RBMK type Nuclear Power Plants (NPP) in Relation of External Events. A 3-D finite element model of Main Building Complex was developed and seismic response analyses were performed taking into account the soil-structure interaction (SSI). The standard mode superposition method was used for evaluation of dynamic response of structure in time domain. The structure was assumed surface founded at the basemat level. Seismic response analyses were carried out considering shear wave propagation pattern for the input motion. The in-structure time histories and response spectra were generated in referenced locations. Conclusions are drawn for the reliability of the structural response evaluation considering the soil-structure interaction effects. (author)
Seismic analysis of a reinforced concrete containment vessel model
International Nuclear Information System (INIS)
Randy, James J.; Cherry, Jeffery L.; Rashid, Yusef R.; Chokshi, Nilesh
2000-01-01
Pre-and post-test analytical predictions of the dynamic behavior of a 1:10 scale model Reinforced Concrete Containment Vessel are presented. This model, designed and constructed by the Nuclear Power Engineering Corp., was subjected to seismic simulation tests using the high-performance shaking table at the Tadotsu Engineering Laboratory in Japan. A group of tests representing design-level and beyond-design-level ground motions were first conducted to verify design safety margins. These were followed by a series of tests in which progressively larger base motions were applied until structural failure was induced. The analysis was performed by ANATECH Corp. and Sandia National Laboratories for the US Nuclear Regulatory Commission, employing state-of-the-art finite-element software specifically developed for concrete structures. Three-dimensional time-history analyses were performed, first as pre-test blind predictions to evaluate the general capabilities of the analytical methods, and second as post-test validation of the methods and interpretation of the test result. The input data consisted of acceleration time histories for the horizontal, vertical and rotational (rocking) components, as measured by accelerometers mounted on the structure's basemat. The response data consisted of acceleration and displacement records for various points on the structure, as well as time-history records of strain gages mounted on the reinforcement. This paper reports on work in progress and presents pre-test predictions and post-test comparisons to measured data for tests simulating maximum design basis and extreme design basis earthquakes. The pre-test analyses predict the failure earthquake of the test structure to have an energy level in the range of four to five times the energy level of the safe shutdown earthquake. The post-test calculations completed so far show good agreement with measured data
Yilmaz, Zeynep
Typically, the vertical component of the ground motion is not considered explicitly in seismic design of bridges, but in some cases the vertical component can have a significant effect on the structural response. The key question of when the vertical component should be incorporated in design is answered by the probabilistic seismic hazard assessment study incorporating the probabilistic seismic demand models and ground motion models. Nonlinear simulation models with varying configurations of an existing bridge in California were considered in the analytical study. The simulation models were subjected to the set of selected ground motions in two stages: at first, only horizontal components of the motion were applied; while in the second stage the structures were subjected to both horizontal and vertical components applied simultaneously and the ground motions that produced the largest adverse effects on the bridge system were identified. Moment demand in the mid-span and at the support of the longitudinal girder and the axial force demand in the column are found to be significantly affected by the vertical excitations. These response parameters can be modeled using simple ground motion parameters such as horizontal spectral acceleration and vertical spectral acceleration within 5% to 30% error margin depending on the type of the parameter and the period of the structure. For a complete hazard assessment, both of these ground motion parameters explaining the structural behavior should also be modeled. For the horizontal spectral acceleration, Abrahamson and Silva (2008) model was used within many available standard model. A new NGA vertical ground motion model consistent with the horizontal model was constructed. These models are combined in a vector probabilistic seismic hazard analyses. Series of hazard curves developed and presented for different locations in Bay Area for soil site conditions to provide a roadmap for the prediction of these features for future
Statistical determination of significant curved I-girder bridge seismic response parameters
Seo, Junwon
2013-06-01
Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.
Seismic risk analysis for the Babcock and Wilcox facility, Leechburg, Pennsylvania
International Nuclear Information System (INIS)
1977-01-01
The results of a detailed seismic risk analysis of the Babcock and Wilcox Plutonium Fuel Fabrication facility at Leechburg, Pennsylvania are presented. This report focuses on earthquakes; the other natural hazards, being addressed in separate reports, are severe weather (strong winds and tornados) and floods. The calculational method used is based on Cornell's work (1968); it has been previously applied to safety evaluations of major projects. The historical seismic record was established after a review of available literature, consultation with operators of local seismic arrays and examination of appropriate seismic data bases. Because of the aseismicity of the region around the site, an analysis different from the conventional closest approach in a tectonic province was adapted. Earthquakes as far from the site as 1,000 km were included, as were the possibility of earthquakes at the site. In addition, various uncertainties in the input were explicitly considered in the analysis. The results of the risk analysis, which include a Bayesian estimate of the uncertainties, are presented, expressed as return period accelerations. The best estimate curve indicates that the Babcock and Wilcox facility will experience 0.05 g every 220 years and 0.10 g every 1400 years. The bounding curves roughly represent the one standard deviation confidence limits about the best estimate, reflecting the uncertainty in certain of the input. Detailed examination of the results show that the accelerations are very insensitive to the details of the source region geometries or the historical earthquake statistics in each region and that each of the source regions contributes almost equally to the cumulative risk at the site. If required for structural analysis, acceleration response spectra for the site can be constructed by scaling the mean response spectrum for alluvium in WASH 1255 by these peak accelerations
Seismic response of concrete gravity dams with finite reservoir
International Nuclear Information System (INIS)
Baumber, T.; Ghobarah, A.
1992-01-01
In most previous analyses of dam responses to earthquake ground motion, the upstream reservoir is assumed to be infinite in length and completely straight. The meandering nature of the river system, however, results in the creation of a finite length reservoir upstream of the dam structure. A study was carried out to examine the effects of the finite length of the reservoir on the dynamic behavior of the monolith. The effect of excitation of the far end of the boundary on the monolith's response is also of interest. The dam-foundation-reservoir system is modelled using a sub-structuring approach. The analysis is conducted in the frequency domain and utilizes the finite element technique. The water in the reservoir is assumed to be compressible, inviscid, and irrotational. The upstream reservoir is assumed to have a rectangular cross-section. It was found that the finite length reservoir assumption results in supplementary response peaks in the monolith's response. The finite reservoir length allows the reservoir to resonate both in horizontal and vertical directions. The magnitude and spacing of these supplementary response peaks are dependent on the length of the reservoir. The phase of the ground motion which affects the far end boundary of the reservoir was also found to have a significant effect on the dam monolith's response. 8 refs., 5 figs
Adding seismic broadband analysis to characterize Andean backarc seismicity in Argentina
Alvarado, P.; Giuliano, A.; Beck, S.; Zandt, G.
2007-05-01
Characterization of the highly seismically active Andean backarc is crucial for assessment of earthquake hazards in western Argentina. Moderate-to-large crustal earthquakes have caused several deaths, damage and drastic economic consequences in Argentinean history. We have studied the Andean backarc crust between 30°S and 36°S using seismic broadband data available from a previous ("the CHARGE") IRIS-PASSCAL experiment. We collected more than 12 terabytes of continuous seismic data from 22 broadband instruments deployed across Chile and Argentina during 1.5 years. Using free software we modeled full regional broadband waveforms and obtained seismic moment tensor inversions of crustal earthquakes testing for the best focal depth for each event. We also mapped differences in the Andean backarc crustal structure and found a clear correlation with different types of crustal seismicity (i.e. focal depths, focal mechanisms, magnitudes and frequencies of occurrence) and previously mapped terrane boundaries. We now plan to use the same methodology to study other regions in Argentina using near-real time broadband data available from the national seismic (INPRES) network and global seismic networks operating in the region. We will re-design the national seismic network to optimize short-period and broadband seismic station coverage for different network purposes. This work is an international effort that involves researchers and students from universities and national government agencies with the goal of providing more information about earthquake hazards in western Argentina.
Development of component failure data for seismic risk analysis
International Nuclear Information System (INIS)
Fray, R.R.; Moulia, T.A.
1981-01-01
This paper describes the quantification and utilization of seismic failure data used in the Diablo Canyon Seismic Risk Study. A single variable representation of earthquake severity that uses peak horizontal ground acceleration to characterize earthquake severity was employed. The use of a multiple variable representation would allow direct consideration of vertical accelerations and the spectral nature of earthquakes but would have added such complexity that the study would not have been feasible. Vertical accelerations and spectral nature were indirectly considered because component failure data were derived from design analyses, qualification tests and engineering judgment that did include such considerations. Two types of functions were used to describe component failure probabilities. Ramp functions were used for components, such as piping and structures, qualified by stress analysis. 'Anchor points' for ramp functions were selected by assuming a zero probability of failure at code allowable stress levels and unity probability of failure at ultimate stress levels. The accelerations corresponding to allowable and ultimate stress levels were determined by conservatively assuming a linear relationship between seismic stress and ground acceleration. Step functions were used for components, such as mechanical and electrical equipment, qualified by testing. Anchor points for step functions were selected by assuming a unity probability of failure above the qualification acceleration. (orig./HP)
Accuracy and sensitivity analysis on seismic anisotropy parameter estimation
Yan, Fuyong; Han, De-Hua
2018-04-01
There is significant uncertainty in measuring the Thomsen’s parameter δ in laboratory even though the dimensions and orientations of the rock samples are known. It is expected that more challenges will be encountered in the estimating of the seismic anisotropy parameters from field seismic data. Based on Monte Carlo simulation of vertical transversely isotropic layer cake model using the database of laboratory anisotropy measurement from the literature, we apply the commonly used quartic non-hyperbolic reflection moveout equation to estimate the seismic anisotropy parameters and test its accuracy and sensitivities to the source-receive offset, vertical interval velocity error and time picking error. The testing results show that the methodology works perfectly for noise-free synthetic data with short spread length. However, this method is extremely sensitive to the time picking error caused by mild random noises, and it requires the spread length to be greater than the depth of the reflection event. The uncertainties increase rapidly for the deeper layers and the estimated anisotropy parameters can be very unreliable for a layer with more than five overlain layers. It is possible that an isotropic formation can be misinterpreted as a strong anisotropic formation. The sensitivity analysis should provide useful guidance on how to group the reflection events and build a suitable geological model for anisotropy parameter inversion.
Salton Trough Post-seismic Afterslip, Viscoelastic Response, and Contribution to Regional Hazard
Parker, J. W.; Donnellan, A.; Lyzenga, G. A.
2012-12-01
The El Mayor-Cucapah M7.2 April 4 2010 earthquake in Baja California may have affected accumulated hazard to Southern California cities due to loading of regional faults including the Elsinore, San Jacinto and southern San Andreas, faults which already have over a century of tectonic loading. We examine changes observed via multiple seismic and geodetic techniques, including micro seismicity and proposed seismicity-based indicators of hazard, high-quality fault models, the Plate Boundary Observatory GNSS array (with 174 stations showing post-seismic transients with greater than 1 mm amplitude), and interferometric radar maps from UAVSAR (aircraft) flights, showing a network of aseismic fault slip events at distances up to 60 km from the end of the surface rupture. Finite element modeling is used to compute the expected coseismic motions at GPS stations with general agreement, including coseismic uplift at sites ~200 km north of the rupture. Postseismic response is also compared, with GNSS and also with the CIG software "RELAX." An initial examination of hazard is made comparing micro seismicity-based metrics, fault models, and changes to coulomb stress on nearby faults using the finite element model. Comparison of seismicity with interferograms and historic earthquakes show aseismic slip occurs on fault segments that have had earthquakes in the last 70 years, while other segments show no slip at the surface but do show high triggered seismicity. UAVSAR-based estimates of fault slip can be incorporated into the finite element model to correct Coloumb stress change.
Seismic analysis and structure capacity evaluation of the Belene nuclear power plant
International Nuclear Information System (INIS)
Johnson, J.J.; Hashimoto, P.S.; Campbell, R.D.; Baltus, R.S.
1993-01-01
The seismic analysis and structure capacity evaluation of the Belene Nuclear Power Plant, a two-unit WWER 1000, was performed. The principal objective of the study was to review the major aspects of the seismic design including ground motion specification, foundation concept and materials, and the Unit I main reactor building structure response and capacity. The main reactor building structure /foundation/soil were modeled and analyzed by a substructure approach to soil-structure interaction (SSI) analysis. The elements of the substructure approach, implemented in the family of computer programs CLASSI, are: Specification of the free-field ground motion; Modeling the soil profile; SSI parameters; Modeling the structure; SSI-response analyses. Each of these aspects is discussed. The Belene Unit 1 main reactor building structure was evaluated to verify the seismic design with respect to current western criteria. The structural capacity evaluation included criteria development, element load distribution analysis, structural element selection, and structural element capacity evaluation. Equipment and commodity design criteria were similarly reviewed and evaluated. Methodology results and recommendations are presented. (author)
Seismic analysis of hydraulic control rod driving system
International Nuclear Information System (INIS)
Zheng, Yanhua; Bo, Hanliang; Dong, Duo
2002-01-01
A simplified mathematical model was developed for the Hydraulic Control Rod Driving System (HCRDS) of a 200 MW nuclear heating reactor, which incorporated the design of its chamfer-hole step cylinder, to analyze its seismic response characteristics. The control rod motion was analyzed for different sine-wave vibration loadings on platform vibrator. The vibration frequency domain and the minimum acceleration amplitude of the control rod needed to cause the control rod to step to its next setting were compared with the design acceleration amplitude spectrum. The system design was found to be safety within the calculated limits. The safety margin increased with increasing frequency. (author)
SEISMIC Analysis of high-rise buildings with composite metal damper
Directory of Open Access Journals (Sweden)
Chen Ruixue
2015-01-01
Full Text Available This paper mainly studies on the mechanical characteristics and application effect of composite metal damper in the high-rise buildings via the numerical simulation analysis. The research adopts the elastic and elastic-plastic dynamic approach and the displacement time history response and damper energy dissipation capacity and so on of the high-rise building are compared and analyzed before and after installation. The analysis found that the energy dissipation characteristic of metallic dampers is good. High-rise building story drift significantly is reduced and the extent of damage of the walls and coupling beams is decreased, achieved a good energy dissipation effect. Composite metal damper can effectively and economically improve the seismic performance of high-rise buildings, meet the requirement of the 3-level design for seismic resistance. The result has certain reference significance for the application of metallic damper in the high-rise buildings.
Detailed comparison between computed and measured FBR core seismic responses
International Nuclear Information System (INIS)
Forni, M.; Martelli, A.; Melloni, R.; Bonacina, G.
1988-01-01
This paper presents a detailed comparison between seismic calculations and measurements performed for various mock-ups consisting of groups of seven and nineteen simplified elements of the Italian PEC fast reactor core. Experimental tests had been performed on shaking tables in air and water (simulating sodium) with excitations increasing up to above Safe Shutdown Earthquake. The PEC core-restraint ring had been simulated in some tests. All the experimental tests have been analysed by use of both the one-dimensional computer program CORALIE and the two-dimensional program CLASH. Comparisons have been made for all the instrumented elements, in both the time and the frequency domains. The good agreement between calculations and measurements has confirmed adequacy of the fluid-structure interaction model used for PEC core seismic design verification
Several problems of cumulative effective mass fraction in anti-seismic analysis
International Nuclear Information System (INIS)
Wang Wei; Sheng Feng; Li Hailong; Wen Jing; Luan Lin
2005-01-01
Cumulative Effective Mass Fraction (CEMF) is one of important items which sign the accuracy in antiseismic analysis. Based on the primary theories of CEMF, the paper show the influence of CEMF on the accuracy in antiseismic analysis. Moreover, some advices and ways are given to solve common problems in antiseismic analysis, such as how to increase CEMF, how to avoid the mass's loss because of the torsional frequency's being close to the frequency corresponding to the peak of seismic response spectrum, how to avoid the mass's loss because of the constraints, and so on. (authors)
SiSeRHMap v1.0: a simulator for mapped seismic response using a hybrid model
Grelle, Gerardo; Bonito, Laura; Lampasi, Alessandro; Revellino, Paola; Guerriero, Luigi; Sappa, Giuseppe; Guadagno, Francesco Maria
2016-04-01
The SiSeRHMap (simulator for mapped seismic response using a hybrid model) is a computerized methodology capable of elaborating prediction maps of seismic response in terms of acceleration spectra. It was realized on the basis of a hybrid model which combines different approaches and models in a new and non-conventional way. These approaches and models are organized in a code architecture composed of five interdependent modules. A GIS (geographic information system) cubic model (GCM), which is a layered computational structure based on the concept of lithodynamic units and zones, aims at reproducing a parameterized layered subsoil model. A meta-modelling process confers a hybrid nature to the methodology. In this process, the one-dimensional (1-D) linear equivalent analysis produces acceleration response spectra for a specified number of site profiles using one or more input motions. The shear wave velocity-thickness profiles, defined as trainers, are randomly selected in each zone. Subsequently, a numerical adaptive simulation model (Emul-spectra) is optimized on the above trainer acceleration response spectra by means of a dedicated evolutionary algorithm (EA) and the Levenberg-Marquardt algorithm (LMA) as the final optimizer. In the final step, the GCM maps executor module produces a serial map set of a stratigraphic seismic response at different periods, grid solving the calibrated Emul-spectra model. In addition, the spectra topographic amplification is also computed by means of a 3-D validated numerical prediction model. This model is built to match the results of the numerical simulations related to isolate reliefs using GIS morphometric data. In this way, different sets of seismic response maps are developed on which maps of design acceleration response spectra are also defined by means of an enveloping technique.
Non-linear Response to a Type of Seismic Input Motion. Additional Information
International Nuclear Information System (INIS)
2011-06-01
This publication reports the results and findings of a coordinated research project on the safety significance of near-field earthquakes in the design of nuclear power plants. It describes the outcome of a benchmark exercise conducted by a number of institutions on the effects of low to moderate magnitude near-field earthquakes, comparing model analytical simulations with the results of a shaking test performed in France on a physical model of a conventional shear-wall structure. The results build the basis for proposals for possible evolution of engineering practices in order to realistically take into account the effects of near-field earthquakes. A CD is attached that contains the List of participants; Summary of the Research Coordination Meetings; Description of the Camus data; Description of the Japanese input motions: near-field earthquakes observed recently in Japan; Description of the output requested of the IAEA CRP participants; Summary of the participants' modelling; Results of Benchmark Step 1, 2 and 3; Scientific background on classification of seismic loads as primary or secondary; and Japanese practice on nonlinear seismic response analysis of safety related important structures.
Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge
Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc
2008-07-01
Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures.
Effect of Ground Motion Characteristics on the Seismic Response of a Monumental Concrete Arch Bridge
International Nuclear Information System (INIS)
Caglayan, B. Ozden; Ozakgul, Kadir; Tezer, Ovunc
2008-01-01
Railway network in Turkey dates back to more than a hundred years ago and according to official records, there are approximately 18,000 railway bridges with spans varying between 50 cm up to 150 meters. One of them is a monumental concrete arch bridge with a total length of 210 meters having three major spans of 30 meters and a height of 65 meters, located in an earthquake-prone region in southern part of the country. Three-dimensional finite element model of the bridge was generated using a commercially available general finite element analysis software and based on the outcomes of a series of in-depth acceleration measurements that were conducted on-site, the model was refined. Types of ground motion records were used to investigate the seismic response and vulnerability of this massive structure in order to provide information regarding (i) damage-susceptible regions of the structure for monitoring purposes, and, (ii) seismic loads to be taken into account during evaluation and possible strengthening phases for this type of structures
Non-linear Response to a Type of Seismic Input Motion
International Nuclear Information System (INIS)
2011-06-01
This publication reports the results and findings of a coordinated research project on the safety significance of near-field earthquakes in the design of nuclear power plants. It describes the outcome of a benchmark exercise conducted by a number of institutions on the effects of low to moderate magnitude near-field earthquakes, comparing model analytical simulations with the results of a shaking test performed in France on a physical model of a conventional shear-wall structure. The results build the basis for proposals for possible evolution of engineering practices in order to realistically take into account the effects of near-field earthquakes. A CD is attached that contains the List of participants; Summary of the Research Coordination Meetings; Description of the CAMUS data; Description of the Japanese input motions: near-field earthquakes observed recently in Japan; Description of the output requested of the IAEA CRP participants; Summary of the participants' modelling; Results of Benchmark Step 1, 2 and 3; Scientific background on classification of seismic loads as primary or secondary; and Japanese practice on nonlinear seismic response analysis of safety related important structures.
Simulation of Seismic Response of Reinforced Concrete Beam-Column Joints with Nurbs Surface Fitting
Directory of Open Access Journals (Sweden)
Mirhosseini R. Tabatabaei
2017-09-01
Full Text Available This paper presents an approach based on NURBS (non-uniform rational B-splines to achieve a seismic response surface (SRS from a group of points obtained by using an analytical model of RC joints. NURBS based on the genetic algorithm is an important mathematical tool and consists of generalizations of Bezier curves and surfaces and B-splines. Generally, the accuracy of the design process of joints depends on the number of control points that are captured in the results of experimental research on real specimens. The values obtained from the specimens are the best tools to use in seismic analysis, though more expensive when compared to values simulated by SRSs. The SRS proposed in this paper can be applied to obtain surfaces that show site effect results on destructions of beam-column joint, taking into account different site conditions for a specific earthquake. The efficiency of this approach is demonstrated by the retrieval of simulated-versus-analytical results.
Use of a viscoelastic model for the seismic response of base-isolated buildings
International Nuclear Information System (INIS)
Uras, R.A.
1994-01-01
Due to recent developments in elastomer technology, seismic isolation using elastomer bearings is rapidly becoming an acceptable design tool to enhance structural seismic margins and to protect people and equipment from earthquake damage. With proper design of isolators, high-energy seismic input motions are transformed into low-frequency, low energy harmonic motions and the accelerations acting on the isolated building are significantly reduced. Several alternatives exist for the modeling of the isolators. This study is concerned with the use of a viscoelastic model to predict the seismic response of base-isolated buildings. The in-house finite element computer code has been modified to incorporate a viscoelastic spring element, and several simulations are performed. Then, the computed results have been compared with the corresponding observed data recorded at the test facility
CARES-ESTSC, Seismic Structure Safety Analysis for Nuclear Power Plants
International Nuclear Information System (INIS)
Costantino, C.J.; Miller, C.A.; Heymsfield, E.; Yang, A.
1999-01-01
1 - Description of program or function: CARES, Computer Analysis for Rapid Evaluation of Structures, was developed for NRC staff use to determine the validity and accuracy of the analysis methods used by various utilities for structural safety evaluations of nuclear power plants. CARES is organized in a modular format with the basic modules of the system performing static, seismic, and nonlinear analysis. In this release, only the seismic module is implemented. This module defines the design seismic criteria at a given site, evaluates the free-field motion, and computes the structural response and floor response spectra including soil-structure interaction. The eight options in CARES currently are: a general manager for the seismic module, deconvolution analysis, structural data preparation for soil-structure interaction (SSI) analysis, input motion preparation for SSI analysis, SSI analysis, earthquake simulations/data, PSD (Power Spectral Density) related acceleration time history/spectra analysis, and plot generation. 2 - Method of solution: The seismic module works in the frequency domain. Earthquake motion simulation is based on the fundamental property that any periodic function can be expanded in a series of sinusoidal waves. The computer uses a random number generator to produce strings of phase angles with uniform distribution in the 0-2 pi range. Then, a linear correction procedure due to Scanlon and Sacks is employed to derive an adjusted array of amplitudes. The acceleration ensemble is subsequently modified by a deterministic intensity function composed of three segments: an initial buildup, a stationary duration, and exponential steady decay. A parabolic correction procedure outlined by Jennings and Housner is applied to the acceleration ensemble to bring the end velocity of the ground motion to zero. The soil-structure system is represented by a three-dimensional lumped parameter type model. The structural model is built up from three
Seismic margin review of the Maine Yankee Atomic Power Station: Fragility analysis
International Nuclear Information System (INIS)
Ravindra, M.K.; Hardy, G.S.; Hashimoto, P.S.; Griffin, M.J.
1987-03-01
This Fragility Analysis is the third of three volumes for the Seismic Margin Review of the Maine Yankee Atomic Power Station. Volume 1 is the Summary Report of the first trial seismic margin review. Volume 2, Systems Analysis, documents the results of the systems screening for the review. The three volumes are part of the Seismic Margins Program initiated in 1984 by the Nuclear Regulatory Commission (NRC) to quantify seismic margins at nuclear power plants. The overall objectives of the trial review are to assess the seismic margins of a particular pressurized water reactor, and to test the adequacy of this review approach, quantification techniques, and guidelines for performing the review. Results from the trial review will be used to revise the seismic margin methodology and guidelines so that the NRC and industry can readily apply them to assess the inherent quantitative seismic capacity of nuclear power plants
Seismic margin review of the Maine Yankee Atomic Power Station: Fragility analysis
Energy Technology Data Exchange (ETDEWEB)
Ravindra, M. K.; Hardy, G. S.; Hashimoto, P. S.; Griffin, M. J.
1987-03-01
This Fragility Analysis is the third of three volumes for the Seismic Margin Review of the Maine Yankee Atomic Power Station. Volume 1 is the Summary Report of the first trial seismic margin review. Volume 2, Systems Analysis, documents the results of the systems screening for the review. The three volumes are part of the Seismic Margins Program initiated in 1984 by the Nuclear Regulatory Commission (NRC) to quantify seismic margins at nuclear power plants. The overall objectives of the trial review are to assess the seismic margins of a particular pressurized water reactor, and to test the adequacy of this review approach, quantification techniques, and guidelines for performing the review. Results from the trial review will be used to revise the seismic margin methodology and guidelines so that the NRC and industry can readily apply them to assess the inherent quantitative seismic capacity of nuclear power plants.
OVERVIEW ON BNL ASSESSMENT OF SEISMIC ANALYSIS METHODS FOR DEEPLY EMBEDDED NPP STRUCTURES
International Nuclear Information System (INIS)
XU, J.; COSTANTINO, C.; HOFMAYER, C.; GRAVES, H.
2007-01-01
A study was performed by Brookhaven National Laboratory (BNL) under the sponsorship of the U. S. Nuclear Regulatory Commission (USNRC), to determine the applicability of established soil-structure interaction analysis methods and computer programs to deeply embedded and/or buried (DEB) nuclear power plant (NPP) structures. This paper provides an overview of the BNL study including a description and discussions of analyses performed to assess relative performance of various SSI analysis methods typically applied to NPP structures, as well as the importance of interface modeling for DEB structures. There are four main elements contained in the BNL study: (1) Review and evaluation of existing seismic design practice, (2) Assessment of simplified vs. detailed methods for SSI in-structure response spectrum analysis of DEB structures, (3) Assessment of methods for computing seismic induced earth pressures on DEB structures, and (4) Development of the criteria for benchmark problems which could be used for validating computer programs for computing seismic responses of DEB NPP structures. The BNL study concluded that the equivalent linear SSI methods, including both simplified and detailed approaches, can be extended to DEB structures and produce acceptable SSI response calculations, provided that the SSI response induced by the ground motion is very much within the linear regime or the non-linear effect is not anticipated to control the SSI response parameters. The BNL study also revealed that the response calculation is sensitive to the modeling assumptions made for the soil/structure interface and application of a particular material model for the soil
Numerical Simulation Analysis of Seismic of Frame Structure on Hill Terrain
Directory of Open Access Journals (Sweden)
Weng Weisu
2017-01-01
Full Text Available In recent year, Wenchuan,Ya’an,Yushu and other areas in china occur a series of high earthquake, however areas of earthquake is similar as mountainous terrain, building structure of seismic increasingly aroused our concern, and the research that hill topography affected building structure seismic in shallow mountain. The research content mainly includes: through modelling was built by the ANSYS software, the cooperative effects of a ten layer of frame structure- hill system were calculation. First, simple comparative dynamic characteristics analysis of soil - structure interaction and the rigid foundation assumption conditions; Second, put Hill-Soil-Structure Interaction(referred to as HSSI and Soil - Structure - Interaction(referred to as SSI further analysis of the dynamic response, including: including structural modal analysis (vibration mode, cycle, the time history analysis (such as displacement, internal force and acceleration and so on. Through Hill-Soil-Structure Interaction research, taking each factor in consideration, giving structure seismic key technology measures about shallow mountain to provide reference for such structure theory research.
Single Point Vulnerability Analysis of Automatic Seismic Trip System
Energy Technology Data Exchange (ETDEWEB)
Oh, Seo Bin; Chung, Soon Il; Lee, Yong Suk [FNC Technology Co., Yongin (Korea, Republic of); Choi, Byung Pil [KHNP CRI, Daejeon (Korea, Republic of)
2016-10-15
Single Point Vulnerability (SPV) analysis is a process used to identify individual equipment whose failure alone will result in a reactor trip, turbine generator failure, or power reduction of more than 50%. Automatic Seismic Trip System (ASTS) is a newly installed system to ensure the safety of plant when earthquake occurs. Since this system directly shuts down the reactor, the failure or malfunction of its system component can cause a reactor trip more frequently than other systems. Therefore, an SPV analysis of ASTS is necessary to maintain its essential performance. To analyze SPV for ASTS, failure mode and effect analysis (FMEA) and fault tree analysis (FTA) was performed. In this study, FMEA and FTA methods were performed to select SPV equipment of ASTS. D/O, D/I, A/I card, seismic sensor, and trip relay had an effect on the reactor trip but their single failure will not cause reactor trip. In conclusion, ASTS is excluded as SPV. These results can be utilized as the basis data for ways to enhance facility reliability such as design modification and improvement of preventive maintenance procedure.
Single Point Vulnerability Analysis of Automatic Seismic Trip System
International Nuclear Information System (INIS)
Oh, Seo Bin; Chung, Soon Il; Lee, Yong Suk; Choi, Byung Pil
2016-01-01
Single Point Vulnerability (SPV) analysis is a process used to identify individual equipment whose failure alone will result in a reactor trip, turbine generator failure, or power reduction of more than 50%. Automatic Seismic Trip System (ASTS) is a newly installed system to ensure the safety of plant when earthquake occurs. Since this system directly shuts down the reactor, the failure or malfunction of its system component can cause a reactor trip more frequently than other systems. Therefore, an SPV analysis of ASTS is necessary to maintain its essential performance. To analyze SPV for ASTS, failure mode and effect analysis (FMEA) and fault tree analysis (FTA) was performed. In this study, FMEA and FTA methods were performed to select SPV equipment of ASTS. D/O, D/I, A/I card, seismic sensor, and trip relay had an effect on the reactor trip but their single failure will not cause reactor trip. In conclusion, ASTS is excluded as SPV. These results can be utilized as the basis data for ways to enhance facility reliability such as design modification and improvement of preventive maintenance procedure
Seismic analysis of spent nuclear fuel storage racks
International Nuclear Information System (INIS)
Shah, S.J.; Biddle, J.R.; Bennett, S.M.; Schechter, C.B.; Harstead, G.A.; Marquet, F.
1996-01-01
In many nuclear power plants, existing storage racks are being replaced with high-density racks to accommodate the increasing inventory of spent fuel. In the hypothetical design considered here, the high-density arrangement of fuel assemblies, or consolidated fuel canisters, is accomplished through the use of borated stainless steel (BSS) plates acting as neutron absorbers. No structural benefit from the BSS is assumed. This paper describes the methods used to perform seismic analysis of high density spent fuel storage racks. The sensitivity of important parameters such as the effect of variation of coefficients of friction between the rack legs and the pool floor and fuel loading conditions (consolidated and unconsolidated) are also discussed in the paper. Results of this study are presented. The high-density fuel racks are simply supported by the pool floor with no structural connections to adjacent racks or to the pool walls or floor. Therefore, the racks are free standing and may slide and tip. Several time history, nonlinear, seismic analyses are required to account for variations in the coefficient of friction, rack loading configuration, and the type of the seismic event. This paper presents several of the mathematical models usually used. Friction cannot be precisely predicted, so a range of friction coefficients is assumed. The range assumed for the analysis is 0.2 to 0.8. A detailed model representing a single rack is used to evaluate the 3-D loading effects. This model is a controlling case for the stress analysis. A 2-D multi-rack model representing a row of racks between the spent fuel pool walls is used to evaluate the change in gaps between racks. The racks are normally analyzed for the fuel loading conditions of consolidated, full, empty, and half-loaded with fuel assemblies
Energy Technology Data Exchange (ETDEWEB)
R. Quittmeyer
2006-09-25
This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground
International Nuclear Information System (INIS)
R. Quittmeyer
2006-01-01
This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at
Directory of Open Access Journals (Sweden)
Caputa Alicja
2015-10-01
Full Text Available The exploitation of georesources by underground mining can be responsible for seismic activity in areas considered aseismic. Since strong seismic events are connected with rockburst hazard, it is a continuous requirement to reduce seismic risk. One of the most effective methods to do so is blasting in potentially hazardous mining panels. In this way, small to moderate tremors are provoked and stress accumulation is substantially reduced. In this paper we present an analysis of post-blasting events using Full Moment Tensor (MT inversion at the Rudna mine, Poland, underground seismic network. In addition, we describe the problems we faced when analyzing seismic signals. Our studies show that focal mechanisms for events that occurred after blasts exhibit common features in the MT solution. The strong isotropic and small Double Couple (DC component of the MT, indicate that these events were provoked by detonations. On the other hand, post-blasting MT is considerably different than the MT obtained for strong mining events. We believe that seismological analysis of provoked and unprovoked events can be a very useful tool in confirming the effectiveness of blasting in seismic hazard reduction in mining areas.
Evaluation of methods for seismic analysis of nuclear fuel reprocessing plants, part 1
International Nuclear Information System (INIS)
Tokarz, F.J.; Murray, R.C.; Arthur, D.F.; Feng, W.W.; Wight, L.H.; Zaslawsky, M.
1975-01-01
Currently, no guidelines exist for choosing methods of structural analysis to evaluate the seismic hazard of nuclear fuel reprocessing plants. This study examines available methods and their applicability to fuel reprocessing plant structures. The results of this study should provide a basis for establishing guidelines recommending methods of seismic analysis for evaluating future fuel reprocessing plants. The approach taken is: (1) to identify critical plant structures and place them in four categories (structures at or near grade; deeply embedded structures; fully buried structures; equipment/vessels/attachments/piping), (2) to select a representative structure in each of the first three categories and perform static and dynamic analysis on each, and (3) to evaluate and recommend method(s) of analysis for structures within each category. The Barnwell Nuclear Fuel Plant is selected as representative of future commercial reprocessing plants. The effect of site characteristics on the structural response is also examined. The response spectra method of analysis combined with the finite element model for each category is recommended. For structures founded near or at grade, the lumped mass model could also be used. If a time history response is required, a time-history analysis is necessary. (U.S.)
Inelastic seismic response of precast concrete frames with constructed plastic hinges
Sucuoglu, H.
1995-07-01
A modified seismic design concept is introduced for precast concrete frames in which beam plastic hinges with reduced yield capacities are constructed away from the precast beam-column connections arranged at the column faces. Plastic hinge location and yield capacity are employed as the basic parameters of an analytical survey in which the inelastic dynamic responses of a conventional precast frame and its modified counterparts are calculated and compared under two earthquake excitations by using a general purpose computer program for dynamic analysis of inelastic frames (left bracket) 1, 2 (right bracket). An optimum design is obtained by providing plastic hinges on precast beams located at one depth away from the beam ends, in which primary (negative) bending moment yield capacities are reduced between one-third and one-quarter of the beam design end moments. With such plastic hinge configurations, precast beam-column connections at the column faces can be designed to remain elastic under strong earthquake excitations.
International Nuclear Information System (INIS)
Carbonari, S.; Dezi, F.; Leoni, G.
2008-01-01
This paper presents a study on the seismic response of coupled wall-frame structures founded on piles. A complete soil-structure interaction analysis is carried out with reference to a case study. Three different soils and seven real accelerograms are considered. Local site response analyses are performed in order to evaluate the incoming free-field motion at different depths and the ground motion amplifications. A numerical model, accounting for the pile-soil-pile interaction and for material and radiation damping, is used to evaluate the impedance matrix and the foundation input motion. The domain decomposition technique is adopted to perform time-domain seismic analyses introducing Lumped Parameter Models to take into account the impedance of the soil-structure system. Applications show that the rocking phenomena affect the behaviour of the structure by changing the base shear distribution within the wall and the frame and by increasing the structural displacements
International Nuclear Information System (INIS)
MACKEY, T.C.
2006-01-01
M and D Professional Services, Inc. (M and D) is under subcontract to Pacific Northwest National Laboratories (PNNL) to perform seismic analysis of the Hanford Site Double-Shell Tanks (DSTs) in support of a project entitled ''Double-Shell Tank (DSV Integrity Project-DST Thermal and Seismic Analyses)''. The overall scope of the project is to complete an up-to-date comprehensive analysis of record of the DST System at Hanford in support of Tri-Party Agreement Milestone M-48-14. The work described herein was performed in support of the seismic analysis of the DSTs. The thermal and operating loads analysis of the DSTs is documented in Rinker et al. (2004). The overall seismic analysis of the DSTs is being performed with the general-purpose finite element code ANSYS'. The global model used for the seismic analysis of the DSTs includes the DST structure, the contained waste, and the surrounding soil. The seismic analysis of the DSTs must address the fluid-structure interaction behavior and sloshing response of the primary tank and contained liquid. ANSYS has demonstrated capabilities for structural analysis, but has more limited capabilities for fluid-structure interaction analysis. The purpose of this study is to demonstrate the capabilities and investigate the limitations of the finite element code MSC.Dytranz for performing a dynamic fluid-structure interaction analysis of the primary tank and contained waste. To this end, the Dytran solutions are benchmarked against theoretical solutions appearing in BNL 1995, when such theoretical solutions exist. When theoretical solutions were not available, comparisons were made to theoretical solutions to similar problems, and to the results from ANSYS simulations. Both rigid tank and flexible tank configurations were analyzed with Dytran. The response parameters of interest that are evaluated in this study are the total hydrodynamic reaction forces, the impulsive and convective mode frequencies, the waste pressures, and slosh
Seismic Fragility Curves of Industrial Buildings by Using Nonlinear Analysis
Directory of Open Access Journals (Sweden)
Mohamed Nazri Fadzli
2017-01-01
Full Text Available This study presents the steel fragility curves and performance curves of industrial buildings of different geometries. The fragility curves were obtained for different building geometries, and the performance curves were developed based on lateral load, which is affected by the geometry of the building. Three records of far-field ground motion were used for incremental dynamic analysis (IDA, and the design lateral loads for pushover analysis (POA. All designs were based on British Standard (BS 5950; however, Eurocode 8 was preferred for seismic consideration in the analysis because BS 5950 does not specify any seismic provision. The five levels of performance stated by FEMA-273, namely, operational phase, immediate occupancy, damage control, life safety, and collapse prevention (CP were used as main guidelines for evaluating structural performance. For POA, Model 2 had highest base shear, followed by Model 1 and Model 3, even though Model 2 has a smaller structure compared with Model 3. Meanwhile, the fragility curves showed that the probability of reaching or exceeding the CP level of Model 2 is the highest, followed by that of Models 1 and 3.
Scram and nonlinear reactor system seismic analysis for a liquid metal fast reactor
International Nuclear Information System (INIS)
Morrone, A.; Brussalis, W.G.
1975-01-01
The paper presents the analysis and results for a LMFBR system which was analyzed for both scram times and seismic responses such as bending moments, accelerations and forces. The reactor system was represented with a one-dimensional nonlinear mathematical model with two degrees of freedom per node (translational and rotational). The model was developed to incorporate as many reactor components as possible without exceeding computer limitations. It consists of 12 reactor components with a total of 71 nodes, 69 beam and pin-jointed elements and 27 gap elements. The gap elements were defined by their clearances, impact spring constants and impact damping constants based on a 50% coefficient of restitution. The horizontal excitation input to the model was the response of the containment building at the location of the reactor vessel supports. It consists of a ten seconds Safe Shutdown Earthquake acceleration-time history at 0.005 seconds intervals and with a maximum acceleration of 0.408 g. The analysis was performed with two Westinghouse special purpose computer programs. The first program calculated the reactor system seismic responses and stored the impact forces on tape. The impact forces on the control rod driveline were converted into vertical frictional forces by multiplying them by a coefficient of friction, and then used by the second program for the scram time determination. The results give time history plots of various seismic responses, and plots of scram times as a function of control rod travel distance for the most critical scram initiation times. The total scram time considering the effects of the earthquake was still acceptable but about 4 times longer than that calculated without the earthquake. The bending moment and shear force responses were used as input for the structural analysis (stresses, deflections, fatigue) of the various components, in combination with the other applicable loading conditions. (orig./HP) [de
Energy Technology Data Exchange (ETDEWEB)
Suzette Payne
2006-04-01
This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.
Energy Technology Data Exchange (ETDEWEB)
Suzette Payne
2007-08-01
This report summarizes how the effects of the sedimentary interbedded basalt stratigraphy were modeled in the probabilistic seismic hazard analysis (PSHA) of the Idaho National Laboratory (INL). Drill holes indicate the bedrock beneath INL facilities is composed of about 1.1 km of alternating layers of basalt rock and loosely consolidated sediments. Alternating layers of hard rock and “soft” loose sediments tend to attenuate seismic energy greater than uniform rock due to scattering and damping. The INL PSHA incorporated the effects of the sedimentary interbedded basalt stratigraphy by developing site-specific shear (S) wave velocity profiles. The profiles were used in the PSHA to model the near-surface site response by developing site-specific stochastic attenuation relationships.
International Nuclear Information System (INIS)
Oluwasusi, A. B.; Hussey, V.; Goulding, F. J.
2002-01-01
The Oso Field (OML 70) produces approximately 100 TBD of condensate from Miocene age shelfal sand reservoirs at approximately 10,000 feet below sea level. The field was discovered in 1967 while testing a deeply buried fault closure. Reservoirs are normally pressured, exceed 1 Darcy in permeability and range from 50 to 600 feet in thickness.There are seismic amplitudes associated with the shallower reservoirs on the existing conventional 3D dataset; however there are no anomalies associated with the deeper, condensate accumulations.The paper explores the physical rock and fluid properties associated with the Oso reservoirs and the resulting seismic responses. Modelled results have been calibrated with the actual seismic signatures for the water and hydrocarbon bearing zones. Results indicate that the deeper reservoirs exhibit a classic Class II AVG seismic response and that the use of longer offset and angle stack data can help predict the occurrence of these types of reservoirs. Examples of similar accumulations will be shared.Mobil Producing Nigeria is conducting a full reprocessing effort of the existing 3D dataset over the Joint Venture acreage with a goal of identifying and exploiting additional accumulations with Class II AVG seismic response. Preliminary results of the reprocessing over known accumulations will be presented
Seismic fragility analysis of buried steel piping at P, L, and K reactors
International Nuclear Information System (INIS)
Wingo, H.E.
1989-10-01
Analysis of seismic strength of buried cooling water piping in reactor areas is necessary to evaluate the risk of reactor operation because seismic events could damage these buried pipes and cause loss of coolant accidents. This report documents analysis of the ability of this piping to withstand the combined effects of the propagation of seismic waves, the possibility that the piping may not behave in a completely ductile fashion, and the distortions caused by relative displacements of structures connected to the piping
Seismic analysis of a large LMFBR with fluid-structure interactions
International Nuclear Information System (INIS)
Ma, D.C.
1985-01-01
The seismic analysis of a large LMFBR with many internal components and structures is presented. Both vertical and horizontal seismic excitations are considered. The important hydrodynamic phenomena such as fluid-structure interaction, sloshing, fluid coupling and fluid inertia effects are included in the analysis. The results of this study are discussed in detail. Information which is useful to the design of future reactions under seismic conditions is also given. 4 refs., 12 figs
A seismic analysis of Korean standard PWR fuels under transition core conditions
International Nuclear Information System (INIS)
Kim, Hyeong Koo; Park, Nam Kyu; Jang, Young Ki; Kim, Jae Ik; Kim, Kyu Tae
2005-01-01
The PLUS7 fuel is developed to achieve higher thermal performance, burnup and more safety margin than the conventional fuel used in the Korean Standard Nuclear Plants (KSNPs) and to sustain structural integrity under increased seismic requirement in Korea. In this study, a series of seismic analysis have been performed in order to evaluate the structural integrity of fuel assemblies associated with seismic loads in the KSNPs under transition core conditions replacing the Guardian fuel, which is a resident fuel in the KSNP reactors, with the PLUS7 fuel. For the analysis, transition core seismic models have been developed, based on the possible fuel loading patterns. And the maximum impact forces on the spacer grid and various stresses acting on the fuel components have been evaluated and compared with the through-grid strength of spacer grids and the stress criteria specified in the ASME code for each fuel component, respectively. Then three noticeable parameters regarding as important parameters governing fuel assembly dynamic behavior are evaluated to clarify their effects on the fuel impact and stress response. As a result of the study, it has been confirmed that both the PLUS7 and the Guardian fuel sustain their structural integrity under the transition core condition. And when the damping ratio is constant, increasing the natural frequency of fuel assembly results in a decrease in impact force. The fuel assembly flexural stiffness has an effect increasing the stress of fuel assembly, but not the impact force. And the spacer grid stiffness is directly related with the impact force response. (author)
Application of the random vibration approach in the seismic analysis of LMFBR structures
International Nuclear Information System (INIS)
Preumont, A.
1988-01-01
The first part discusses the general topic of the spectral analysis of linear multi-degree-of-freedom structure subjected to a stationary random field. Particular attention is given to structures with non-classical damping and hereditary characteristics. The method is implemented in the computer programme RANDOM. Next, the same concepts are applied to multi-supported structures subjected to a stationary seismic excitation. The method is implemented in the computer programme SEISME. Two related problems are dealt with in the next two chapters: (i) the relation between the input of the random vibration analysis and the traditional ground motion specification for seismic analysis (the Design Response Spectra) and (ii) the application of random vibration techniques to the direct generation of floor response spectra. Finally the problem of extracting information from costly time history analyses is addressed. This study has mainly been concerned with the methodology and the development of appropriate softwares. Some qualitative conclusions have been drawn regarding the expected benefit of the approach. They have been judged promising enough to motivate a benchmark exercise. Specifically, the random vibration approach will be compared to the current approximate methods (response spectrum) and time-history analyses (considered as representative of the true response) for a set of typical structures. The hope is that some of the flaws of the current approximate methods can be removed
French experience in seismic risk analysis and associated research works
International Nuclear Information System (INIS)
Mohammadioun, B.
1984-11-01
This communication reviews the basic principles of the seismic risk analysis for nuclear installations in France practiced by the IPSN of the CEA. The presentation of each stage of the analysis includes an account of the methods used, the difficulties met, and a comparison with the recommendations of the AIEA-SG-S1. First, this paper deals with the sismotectonic analysis and with the definition of two reference earthquakes. Then, the calculation of the ground motion corresponding to the reference earthquakes is presented. A particular attention is paid to the problems of calculation of ground motion in the case of important earthquakes near active faults and to the effect of the soil on these movements. Finally, some criticisms, a description of studies undertaken at the moment and some recommendations are presented [fr
Endurance time method for Seismic analysis and design of structures
International Nuclear Information System (INIS)
Estekanchi, H.E.; Vafai, A.; Sadeghazar, M.
2004-01-01
In this paper, a new method for performance based earthquake analysis and design has been introduced. In this method, the structure is subjected to accelerograms that impose increasing dynamic demand on the structure with time. Specified damage indexes are monitored up to the collapse level or other performance limit that defines the endurance limit point for the structure. Also, a method for generating standard intensifying accelerograms has been described. Three accelerograms have been generated using this method. Furthermore, the concept of Endurance Time has been described by applying these accelerograms to single and multi degree of freedom linear systems. The application of this method for analysis of complex nonlinear systems has been explained. Endurance Time method provides a uniform approach to seismic analysis and design of complex structures that can be applied in numerical and experimental investigations
International Nuclear Information System (INIS)
Kolar, Ladislav
2013-03-01
The seismic risk task assessment task should be structured as follows: (i) Define all reactor unit building structures, components and equipment involved in the creation of an initiating event (IE) induced by an seismic event or contributing to the reliability of reactor unit response to an IE; (ii) construct and estimate of the fragility curves for the building and component groups sub (i); (iii) determine the HCLPF for each group of buildings, components or equipment; (iv) determine the nuclear source's seismic resistance (SME) as the minimum HCLPF from the group of equipment in the risk-dominant scenarios; (v) define the risk-limiting group of components, equipment and building structures to the SME value; (vi) based on the fragility levels, identify component groups for which a more detailed fragility analysis is needed; and (vii) recommend groups of equipment or building structures that should be taken into account with respect to the seismic risk, i.e. such groups of equipment or building structures as exhibit a low seismic resistance (HCLPF) and, at the same time, are involved to a significant extent in the reactor unit's seismic risk (are present in the dominant risk scenarios). (P.A.)
Seismic analysis and design of steel beam - thick slab floor systems
International Nuclear Information System (INIS)
Reed, P.W.
1981-01-01
This paper presents a method for seismic analysis and design of floor systems composed of thick reinforced concrete slabs supported by steel beams. The response spectrum modal analysis is used to determine the dynamic response of an orthotropic finite element model. An approximate approach to find the fundamental frequency is explained, allowing an actual acceleration to be determined. The fundamental mode is found to be a major portion of the overall response, whereas the secondary modes are shown to result in a very small portion of the overall response. Dynamic multipliers for the fundamental mode and significant secondary modes are given for several typical floor layouts. These would be used to find equivalent static stress resultants which are used to design the floor. (orig.)
DARHT Multi-intelligence Seismic and Acoustic Data Analysis
Energy Technology Data Exchange (ETDEWEB)
Stevens, Garrison Nicole [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Van Buren, Kendra Lu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hemez, Francois M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-07-21
The purpose of this report is to document the analysis of seismic and acoustic data collected at the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory for robust, multi-intelligence decision making. The data utilized herein is obtained from two tri-axial seismic sensors and three acoustic sensors, resulting in a total of nine data channels. The goal of this analysis is to develop a generalized, automated framework to determine internal operations at DARHT using informative features extracted from measurements collected external of the facility. Our framework involves four components: (1) feature extraction, (2) data fusion, (3) classification, and finally (4) robustness analysis. Two approaches are taken for extracting features from the data. The first of these, generic feature extraction, involves extraction of statistical features from the nine data channels. The second approach, event detection, identifies specific events relevant to traffic entering and leaving the facility as well as explosive activities at DARHT and nearby explosive testing sites. Event detection is completed using a two stage method, first utilizing signatures in the frequency domain to identify outliers and second extracting short duration events of interest among these outliers by evaluating residuals of an autoregressive exogenous time series model. Features extracted from each data set are then fused to perform analysis with a multi-intelligence paradigm, where information from multiple data sets are combined to generate more information than available through analysis of each independently. The fused feature set is used to train a statistical classifier and predict the state of operations to inform a decision maker. We demonstrate this classification using both generic statistical features and event detection and provide a comparison of the two methods. Finally, the concept of decision robustness is presented through a preliminary analysis where
International Nuclear Information System (INIS)
Maslenikov, O.R.; Johnson, J.J.; Tiong, L.W.; Mraz, M.J.; Bumpus, S.; Gerhard, M.A.
1985-03-01
The SMACS (Seismic Methodology Analysis Chain with Statistics) system of computer programs, one of the major computational tools of the Seismic Safety Margins Research Program (SSMRP), links the seismic input with the calculation of soil-structure interaction, major structure response, and subsystem response. The seismic input is defined by ensembles of acceleration time histories in three orthogonal directions. Soil-structure interaction and detailed structural response are then determined simultaneously, using the substructure approach to SSI as implemented in the CLASSI family of computer programs. The modus operandi of SMACS is to perform repeated deterministic analyses, each analysis simulating an earthquake occurrence. Parameter values for each simulation are sampled from assumed probability distributions according to a Latin hypercube experimental design. The user may specify values of the coefficients of variation (COV) for the distributions of the input variables. At the heart of the SMACS system is the computer program SMAX, which performs the repeated SSI response calculations for major structure and subsystem response. This report describes SMAX and the pre- and post-processor codes, used in conjunction with it, that comprise the SMACS system
Seismic dynamic analysis of Heat Exchangers inside of the Auxiliary Buildings in AP1000{sup T}M NPP
Energy Technology Data Exchange (ETDEWEB)
Di Fonzo, M.; Aragon, J.; Moraleda, F.; Palazuelos, M.; San vicente, J. L.
2011-07-01
Seismic dynamic analysis was carried out for the Heat Exchangers (RNS-HR) located inside of the Auxiliary Building in AP 1000{sup T}M NPP. The main function of the RNS-HX is to provide shutdown reactor cooling. These equipment's are safety-related. So the seismic analysis was done using the methodology for Seismic Category I (SCI) structures. The most important topic is that the RNS-HX shall withstand the effects of the Safe Shutdown Earthquake (SSE) and maintain the specified design functions. for the analysis, two finite element models (FEM) were built in order to investigate the structural response of the couple system of building and equipment. The response spectra method was used. The floor response spectra (FRS) at the slab-wall connection were used as input Lateral seismic restrain was necessary to added in order to achieve the natural frequency of 33 Hz. The global structural response was obtained by means of the modal combination method indicated in the Regulatory Guide 1.92.
International Nuclear Information System (INIS)
Park, Jinkyun; Kim, Yochan; Kim, Jung Han; Jung, Wondea; Jang, Seung Cheol
2015-01-01
Highlights: • Response times under seismic events are necessary for human reliability analysis. • Conceptual framework to estimate response times under a seismic event is suggested. • Four kinds of representative contexts in seismic events are considered. • Rules for estimating response times on the representative contexts are extracted. - Abstract: After the Fukushima accident, a couple of novel issues have raised in terms of the safety assessment of nuclear power plants (NPPs). This means that the performance of human operators should be properly evaluated under an extreme event. However, it is unrealistic to collect a sufficient amount of human performance data from a real event, such as a great earthquake. As one of the promising solutions, a conceptual framework is suggested in this paper, which is helpful for estimating the response time data of human operators working in the main control room of NPPs under a seismic event. To this end, the four kinds of representative contexts that could be anticipated from seismic events are identified. Then the response times of human operators who are faced with similar contexts are reviewed from existing literatures and databases. As a result, a couple of rules that allow us to extrapolate the response times of human operators under seismic events are extracted. Although underlying rationales being used for determining these rules are still arguable, it is expected that response times under seismic events could be properly understood along with accumulating those of human operators against non-seismic conditions
Two-dimensional vertical model seismic test and analysis for HTGR core
International Nuclear Information System (INIS)
Ikushima, Takeshi; Honma, Toshiaki.
1983-02-01
The resistance against earthquakes of high-temperature gas cooled reactor (HTGR) core with block-type fuels is not fully ascertained yet. Seismic studies must be made if such a reactor plant is to be installed in areas with frequent earthquakes. In the paper the test results of seismic behavior of a half-scale two-dimensional vertical slice core model and analysis are presented. The following results were obtained: (1) With soft spring support of the fixed side reflector structure, the relative column displacement is larger than that for hand support but the impact reaction force is smaller. (2) In the case of hard spring support the dowel force is smaller than for soft support. (3) The relative column displacement is larger in the core center than at the periphery. The impact acceleration (force) in the center is smaller than at the periphery. (4) The relative column displacement and impact reaction force are smaller with the gas pressure simulation spring than without. (5) With decreasing gap width between the top blocks of columns, the relative column displacement and impact reaction force decrease. (6) The column damping ratio was estimated as 4 -- 10% of critical. (7) The maximum impact reaction force for random waves such as seismic was below 60% that for a sinusoidal wave. (8) Vibration behavior and impact response are in good agreement between test and analysis. (author)
Response of Radon in a seismic calibration explosion, Israel
International Nuclear Information System (INIS)
Zafrir, H.; Steinitz, G.; Malik, U.; Haquin, G.; Gazit-Yaari, N.
2009-01-01
Radon measurements were performed at shallow levels during an in-land 20-ton seismic calibration explosion experiment, simulating a 2.6-M L earthquake, to investigate the influence of the explosive blast and the transitory seismic wave fields on the Radon transport in the country rock, adjacent to the focus of the explosion. The experiment was conducted in a basalt quarry in the northern margin of the Beit Shean valley (Israel). Five gamma-ray sensors were placed, at a depth of about 2 m, along a line located 17-150 m from the edge of the explosion zone. Measurements commenced 4 days before and continued for 9 days after the explosion with 15 min integrations. A 10-s sampling was used in the interval of several hours before and after the explosion itself. Diurnal variations of Radon, reflecting the typical variation pattern of Radon in the shallow environment, were registered before and after the explosion. No significant change in the overall Radon concentration was observed as a consequence of the main explosion as well as three smaller experimental shots (0.5-2 tons) in the 2 h prior to the calibration blast. The seismological data indicate that the transient excess pressure at the farthest Radon sensor was above 5 bar m -1 during 0.2-0.4 s, and evidently much higher at the nearest sensors, but none of the sensors responded by recording any exceptional change in the Radon concentration. Moreover the hypothesis that additional Radon may emanate from solid grains as a result of the excess local pressure exerted by the blast is also not observed. In contrast to a real earthquake event an explosion experiment has neither eventual preceding nor following geodynamic activity. Therefore the absence of significant Radon anomalies during or after the blast does not contradict assumptions, observations or conclusions as the occurrence of Radon anomalies prior or after an earthquake event due to associated long-term geodynamic processes.
Directory of Open Access Journals (Sweden)
El Abbas N.
2016-01-01
Full Text Available This work deals with seismic analysis of structures by taking into account soil-structure interaction where the structure is modeled by an equivalent flexible beam mounted on a rigid foundation that is supported by a Winkler like soil. The foundation is assumed to undergo local uplift and the rotations are considered to be large. The coupling of the system is represented by a series of springs and damping elements that are distributed over the entire width of the foundation. The non-linear equations of motion of the system were derived by taking into account the equilibrium of the coupled foundation-structure system where the structure was idealized as a single-degree-of-freedom. The seismic response of the structure was calculated under the occurrence of foundation uplift for both large and small rotations. The non-linear differential system of equations was integrated by using the Matlab command ode15s. The maximum response has been determined as function of the intensity of the earthquake, the slenderness of the structure and the damping ratio. It was found that considering local uplift with small rotations of foundation under seismic loading leads to unfavorable structural response in comparison with the case of large rotations.
Application of new developments in coupled seismic analysis of piping systems
International Nuclear Information System (INIS)
Gupta, A.; Gupta, A.K.
1995-01-01
The current practice of calculating the seismic response is to perform the analysis of the primary structure (buildings) and the secondary systems (piping) separately. Earthquake input to the primary system in terms of a design response spectrum. An acceleration time history compatible with the design response spectrum is developed (a non-unique process) and primary system is analyzed to obtain the acceleration histories at the desired floors. Floor time histories are used for generating the corresponding instructure response spectrum (IRIS). The instructure response spectra are used as input at the supports of secondary systems. Further, in case of multiple supports, an envelope spectrum (introducing conservatism) is obtained from the individual support IRS. The effect of relative support motion is incorporated by a worst-case separate static analysis (adding to the conservatism). In the above method, mass interaction between the secondary and primary system is ignored, which may have significant effect at resonant frequencies (further adding to the conservatism). The calculated response may be an order of magnitude higher than they should be. Two computer programs, CREST and CREST-IRIS, were developed at Center for NUclear Power Plant Structures, Equipment and Piping. Any one of the two computer programs together with a piping analysis program can be used to perform an accurate coupled seismic analysis of piping systems. The two computer programs have been validated against the time history analysis for simple problems. In the present study, we have applied CREST to analyze two real-life piping systems. The piping analysis program used in this research is the commercial software PIPESTRESS, developed by DST Computer Services of Geneva, Switzerland. (author). 4 refs., 3 figs., 2 tabs
Effect of viscosity on seismic response of waste storage tanks
International Nuclear Information System (INIS)
Tang, Yu; Uras, R.A.; Chang, Yao-Wen.
1992-06-01
The dynamic response of liquid-storage tanks subjected to harmonic excitations and earthquake ground motions has been studied. A rigid tank of negligible mass, rigidly supported at the base having a diameter of 50 ft. and fluid height of 20.4 ft. was used in the computer analysis. The liquid is assumed to have a density of 1.5 g/ml. Viscosity values, μ = 60, 200, 100, and 10,000 cP, were used in the numerical analyses to study the effects of viscosity on sloshing wave height, impulsive and convective pressure on the tank wall, base shear and base moments. Harmonic excitations as well as earthquake ground motions were used as input motions. The harmonic excitations used in the analyses covers a wide range of frequencies, including both the resonant and non-resonant frequencies. Two earthquake motions were used. One matches the Newmark-Hall median response spectrum and is anchored at 0.24 g for a rock site with a damping of 2% and a time duration of 10 s. The other is the 1978 Tabas earthquake which had a peak ZPA of 0.81 g and a time duration of 29 s. A small tank, about 1/15 the size of the typical waste storage tank, was used in the harmonic excitation study to investigate the effect of viscosity on the response of liquid-storage tanks and how the viscosity effect is affected by the size of the storage tank. The results of this study show that for the typical waste storage tank subjected to earthquake motions, the effect of viscosity on sloshing wave height and impulsive and convective pressures is very small and can be neglected. For viscosity effect to become noticeable in the response of the typical waste storage tank, the waste viscosity must be greater than 10,000 cP. This value is far greater than the estimated viscosity value of the high level wastes, which may range from 60 to 200 cP for some tanks
Estimation of reservoir fluid volumes through 4-D seismic analysis on Gullfaks
Energy Technology Data Exchange (ETDEWEB)
Veire, H.S.; Reymond, S.B.; Signer, C.; Tenneboe, P.O.; Soenneland, L.; Schlumberger, Geco-Prakla
1998-12-31
4-D seismic has the potential to monitor hydrocarbon movement in reservoirs during production, and could thereby supplement the predictions of reservoir parameters offered by the reservoir simulator. However 4-D seismic is often more band limited than the vertical resolution required in the reservoir model. As a consequence the seismic data holds a composite response from reservoir parameter changes during production so that the inversion becomes non-unique. A procedure where data from the reservoir model are integrated with seismic data will be presented. The potential of such a procedure is demonstrated through a case study from a recent 4-D survey over the Gullfaks field. 2 figs.
Effects of relay chatter in seismic probabilistic safety analysis
International Nuclear Information System (INIS)
Reed, J.W.; Shiu, K.K.
1985-01-01
In the Zion and Indian Point Probabilistic Safety Studies, relay chatter was dismissed as a credible event and hence was not formally included in the analyses. Although little discussion is given in the Zion and Indian Point PSA documentation concerning the basis for this decision, it has been expressed informally that it was assumed that the operators will be able to reset all relays in a timely manner. Currently, it is the opinion of many professionals that this may be an oversimplification. The three basic areas which must be considered in addressing relay chatter include the fragility of the relays per se, the reliability of the operators to reset the relays and finally the systems response aspects. Each of these areas is reviewed and the implications for seismic PSA are discussed. Finally, recommendations for future research are given
Energy Technology Data Exchange (ETDEWEB)
Fernandez Ares, Antonio, E-mail: antonio.fernandez@rizzoassoc.com [Paul C. Rizzo Associates, Inc., 500 Penn Center Boulevard, Penn Center East, Suite 100, Pittsburgh, PA 15235 (United States); Fatehi, Ali, E-mail: ali.fatehi@rizzoassoc.com [Paul C. Rizzo Associates, Inc., 500 Penn Center Boulevard, Penn Center East, Suite 100, Pittsburgh, PA 15235 (United States)
2013-06-15
Research highlights: ► Site-specific seismic hazard study and suggestions for overcoming those challenges that are inherent to the significant amounts of epistemic uncertainty for sites at remote locations. ► Main aspects of probabilistic seismic hazard analysis (PSHA). ► Regional and site geology in the context of a probabilistic seismic hazard analysis (PSHA), including state-of-the-art ground motion estimation methods, and geophysical conditions. ► Senior seismic hazard analysis (SSHAC) as a mean to incorporate the opinions and contributions of the informed scientific community. -- Abstract: This article provides guidance to conduct a site-specific seismic hazard study, giving suggestions for overcoming those challenges that are inherent to the significant amounts of epistemic uncertainty for sites at remote locations. The text follows the general process of a seismic hazard study, describing both the deterministic and probabilistic approaches. Key and controversial items are identified in the areas of recorded seismicity, seismic sources, magnitude, ground motion models, and local site effects. A case history corresponding to a seismic hazard study in the Middle East for a Greenfield site in a remote location is incorporated along the development of the recommendations. Other examples of analysis case histories throughout the World are presented as well.
Model Solutions for Performance-Based Seismic Analysis of an Anchored Sheet Pile Quay Wall
C. J. W. Habets; D. J. Peters; J. G. de Gijt; A. V. Metrikine; S. N. Jonkman
2016-01-01
Conventional seismic designs of quay walls in ports are mostly based on pseudo-static analysis. A more advanced alternative is the Performance-Based Design (PBD) method, which evaluates permanent deformations and amounts of (repairable) damage under seismic loading. The aim of this study is to investigate the suitability of this method for anchored sheet pile quay walls that were not purposely designed for seismic loads. A research methodology is developed in which pseudo-static, permanent-di...
Cheng, Fei; Liu, Jiangping; Wang, Jing; Zong, Yuquan; Yu, Mingyu
2016-11-01
A boulder stone, a common geological feature in south China, is referred to the remnant of a granite body which has been unevenly weathered. Undetected boulders could adversely impact the schedule and safety of subway construction when using tunnel boring machine (TBM) method. Therefore, boulder detection has always been a key issue demanded to be solved before the construction. Nowadays, cross-hole seismic tomography is a high resolution technique capable of boulder detection, however, the method can only solve for velocity in a 2-D slice between two wells, and the size and central position of the boulder are generally difficult to be accurately obtained. In this paper, the authors conduct a multi-hole wave field simulation and characteristic analysis of a boulder model based on the 3-D elastic wave staggered-grid finite difference theory, and also a 2-D imaging analysis based on first arrival travel time. The results indicate that (1) full wave field records could be obtained from multi-hole seismic wave simulations. Simulation results describe that the seismic wave propagation pattern in cross-hole high-velocity spherical geological bodies is more detailed and can serve as a basis for the wave field analysis. (2) When a cross-hole seismic section cuts through the boulder, the proposed method provides satisfactory cross-hole tomography results; however, when the section is closely positioned to the boulder, such high-velocity object in the 3-D space would impact on the surrounding wave field. The received diffracted wave interferes with the primary wave and in consequence the picked first arrival travel time is not derived from the profile, which results in a false appearance of high-velocity geology features. Finally, the results of 2-D analysis in 3-D modeling space are comparatively analyzed with the physical model test vis-a-vis the effect of high velocity body on the seismic tomographic measurements.
International Nuclear Information System (INIS)
1998-01-01
The Coordinated research program on Intercomparison of analysis methods for seismically isolated nuclear structures involved participants from Italy, Japan, Republic of Korea, Russia, United Kingdom, USA, EC. The purpose of the meeting was to review the progress on the finite element prediction of the force-deformation behaviour of seismic isolators and to discuss the first set of analytical results for the prediction of the response of base-oscillated structures to earthquake inputs. The intercomparison of predictions of bearing behaviour has identified important unexpected issues requiring deeper investigation
Dynamic Behaviour and Seismic Response of Ground Supported Cylindrical Water Tanks
Asha, Joseph; Glory, Joseph
2018-05-01
Liquid storage tank such as in water distribution systems, petroleum plants etc., constitute a vital component of life line systems. Reducing earthquake effects on liquid storage tanks, to minimize the environmental and economic impact of these effects, have always been an important engineering concern. In this paper, the dynamic behavior of cylindrical ground supported concrete water tanks with different aspect ratios is investigated using finite element software ANSYS. The natural frequencies and modal responses are obtained for impulsive and convective modes of vibration. The natural frequency of vibration of the tank is observed to be the lowest at maximum water depth. The fundamental impulsive frequency increases as water level reduces and for water level less than 1/3 of tank height, there is significantly no change in impulsive frequency. The effect of wall flexibility on dynamic behavior of the tank is investigated by performing the modal analysis of flexible and rigid tanks. For a partially filled tank, the results of the present study are of significant relevance. The response of the tank to the transient loading as horizontal ground motion of El Centro earthquake is studied for various water heights. As the height of water on the tank increases, the ultimate maximum seismic response parameters are also observed to be increased. The location of maximum hoop stress varies in accordance with the variations in input ground motion and water fill condition whereas shear and bending moment are maximum at the base.
Active seismic response control systems for nuclear power plant equipment facilities
International Nuclear Information System (INIS)
Kobori, Takuji; Kanayama, Hiroo; Kamagata, Shuichi
1989-01-01
To sustain severe earthquake ground motion, a new type of anti-seismic structure is proposed, called a Dynamic Intelligent Building (DIB) system, which is positioned as an active seismic response controlled the structure. The structural concept starts from a new recognition of earthquake ground motion, and the structural natural frequency is actively adjusted to avoid resonant vibration, and similarly the external counter-force cancels the resonant force which comes from the dynamic structural motion energy. These concepts are verified using an analytical simulator program. The advanced application of the DIB system, is the Active Supporting system and the Active Stabilizer system for nuclear power plant equipment facilities. (orig.)
Afonin, Nikita; Kozlovskaya, Elena
2016-04-01
Understanding inner structure of seismogenic faults and their ability to reactivate is particularly important in investigating the continental intraplate seismicity regime. In our study we address this problem using analysis of ambient seismic noise recorded by the temporary DAFNE array in northern Fennoscandian Shield. The main purpose of the DAFNE/FINLAND passive seismic array experiment was to characterize the present-day seismicity of the Suasselkä post-glacial fault (SPGF) that was proposed as one potential target for the DAFNE (Drilling Active Faults in Northern Europe) project. The DAFNE/FINLAND array comprised the area of about 20 to 100 km and consisted of 8 short-period and 4 broad-band 3-component autonomous seismic stations installed in the close vicinity of the fault area. The array recorded continuous seismic data during September, 2011-May, 2013. Recordings of the array have being analyzed in order to identify and locate natural earthquakes from the fault area and to discriminate them from the blasts in the Kittilä Gold Mine. As a result, we found several dozens of natural seismic events originating from the fault area, which proves that the fault is still seismically active. In order to study the inner structure of the SPGF we use cross-correlation of ambient seismic noise recorded by the array. Analysis of azimuthal distribution of noise sources demonstrated that that during the time interval under consideration the distribution of noise sources is close to the uniform one. The continuous data were processed in several steps including single station data analysis, instrument response removal and time-domain stacking. The data were used to estimate empirical Green's functions between pairs of stations in the frequency band of 0.1-1 Hz and to calculate correspondent surface wave dispersion curves. After that S-wave velocity models were obtained as a result of dispersion curves inversion using Geopsy software. The results suggest that the area of
A seismic analysis of the driving system for the pulsed reactor
International Nuclear Information System (INIS)
Hu Yongtao; Fu Shixiang; Zeng Jianhua; Hong Jingfeng
1991-01-01
The driving system of the pulsed reactor contains control rods, pulsing o rod and sample rack. They are slender, and their drive function is required more strictly. First, a complete model which contains all driving system and reactor bridge is used. Then the substructure models are adopted. The results of calculation are compared with the experimental results. It shows that the analysis results are reliable and the substructure method is simple, available and utility. The seismic safety is evaluated by the results from response spectra method
International Nuclear Information System (INIS)
Lee, T.H.; Thompson, R.W.; Charman, C.M.
1983-01-01
The effects of soil-structure interaction during seismic events upon the dynamic response of a High Temperature Gas-Cooled Reactor plant (HTGR) have been investigated for both surface-founded and embedded basemats. The influence from foundation embedment has been quantitatively assessed through a series of theoretical studies on plants of various sizes. The surface-founded analyses were performed using frequency-independent soil impedance parameters, while the embedded plant analyses utilized finite element models simulated on the FLUSH computer program. The seismic response of the surface-founded plants has been used to establish the standard-site design in-structure response spectra. These analyses were performed by using the linear modal formulation based on conventional soil stiffness and damping values. They serve as reference solutions to which the response data of the corresponding embedded plants are compared. In these comparison studies the responses of embedded plants were generally found to be lower than those of the corresponding surface-founded plants. Additional studies on the surface-founded plants have recently been performed by considering inelastic soil behavior. These inelastic solutions, which treat the soil as an elasto-plastic medium exhibiting hysteretic unloading-reloading characteristics in time, have reduced the response of surface-founded plants. Numerical results are presented in terms of in-structure response spectra along with other pertinent seismic load data at key levels of the plant. Analysis techniques for future studies using viscoelastic halfspace representation and inelastic finite element modeling for soil are also discussed
Effect of gravity loading on inelastic seismic response of reinforced concrete structures
International Nuclear Information System (INIS)
Chowdhury, Rajib; Reddy, G. Rami; Roy, Raghupati; Dutta, Sekhar Chandra
2003-01-01
The effect of gravity loading is not considered in inelastic seismic response to avoid complexity and to reduce the number of influencing parameters. However, the possibility of considerable effect of this factor is indicated in many studies on inelastic seismic behaviour of structures. Hence, it is necessary to study the nature and extent of this effect on inelastic seismic behaviour of structures. The present paper attempts to fulfill this objective by studying the variation of energy dissipation due to presence of various level of axial load. The study is further extended to see the effect of axial force due to gravity loading on the ductility demand of hysteretic energy demand arising in structural elements of a simple one storey structures. The study shows that the presence of axial force may increase the energy dissipation capacity of structure leading to a reduction in ductility demand. (author)
Seismic stratigraphy and regional unconformity analysis of Chukchi Sea Basins
Agasheva, Mariia; Karpov, Yury; Stoupakova, Antonina; Suslova, Anna
2017-04-01
Russian Chukchi Sea Shelf one of petroleum potential province and still one of the most uninvestigated area. North and Sough Chukchi Trough that separated by Wrangel-Hearld Arch have different origin. The main challenge is stratigraphic sequences determination that filled North and South Chukchi basins. The joint tectonic evolution of the territory as Canada basin opening and Brooks Range-Wrangel Herald orogenic events enable to expect the analogous stratigraphy sequences in Russian Part. Analysis of 2D seismic data of Russian and American Chukchi Sea represent the major seismic reflectance that traced throughout the basins. Referring to this data North Chukchi basin includes four seismic stratigraphic sequences - Franklian (pre-Mississippian), Ellesmirian (Upper Devonian-Jurassic), Beaufortian (Jurassic-Lower Cretaceous) and Brookian (Lower Cretaceous-Cenozoic), as it is in North Slope Alaska [1]. South Chukchi basin has different tectonic nature, representing only Franclian basement and Brookian sequences. Sedimentary cover of North Chukchi basins starts with Ellesmirian sequence it is marked by bright reflector that separates from chaotic folded Franklian sequence. Lower Ellesmirian sequence fills of grabens that formed during upper Devonian rifting. Devonian extension event was initiated as a result of Post-Caledonian orogenic collapse, terminating with the opening of Arctic oceans. Beaufortian sequence is distinguished in Colville basin and Hanna Trough by seismically defined clinoforms. Paleozoic and Mesozoic strata are eroded by regional Lower Cretaceous Unconformity (LCU) linked with Canada basin opening. LCU is defined at seismic by angular unconformity, tracing at most arctic basins. Lower Cretaceous erosion and uplift event are of Hauterivian to Aptian age in Brooks Range and the Loppa High uplift refer to the early Barremian. The Lower Cretaceous clinoform complex downlaps to LCU horizon and filling North Chukchi basin (as in Colville basin Alska
Earthquake prediction in Japan and natural time analysis of seismicity
Uyeda, S.; Varotsos, P.
2011-12-01
' (SES) data are available as in Greece, the natural time analysis of the seismicity after the initiation of the SES allows the determination of the time window of the impending mainshock through the evolution of the value of κ1 itself. It was found to work also for the 1989 M7.1 Loma Prieta earthquake. If SES data are not available, we solely rely on the evolution of the fluctuations of κ1 obtained by computing κ1 values using a natural time window of certain length sliding through the earthquake catalog. The fluctuations of the order parameter, in terms of variability, i. e., standard deviation divided by average, was found to increase dramatically when approaching the 11 March M9 super- giant earthquake. In fact, such increase was also found for M7.1 Kobe in 1995, M8.0 Tokachi-oki in 2003 and Landers and Hector-Mines earthquakes in Southern California. It is worth mentioning that such increase is obtained straghtforwardly from ordinary earthquake catalogs without any adjustable parameters.
Surface-Source Downhole Seismic Analysis in R
Thompson, Eric M.
2007-01-01
This report discusses a method for interpreting a layered slowness or velocity model from surface-source downhole seismic data originally presented by Boore (2003). I have implemented this method in the statistical computing language R (R Development Core Team, 2007), so that it is freely and easily available to researchers and practitioners that may find it useful. I originally applied an early version of these routines to seismic cone penetration test data (SCPT) to analyze the horizontal variability of shear-wave velocity within the sediments in the San Francisco Bay area (Thompson et al., 2006). A more recent version of these codes was used to analyze the influence of interface-selection and model assumptions on velocity/slowness estimates and the resulting differences in site amplification (Boore and Thompson, 2007). The R environment has many benefits for scientific and statistical computation; I have chosen R to disseminate these routines because it is versatile enough to program specialized routines, is highly interactive which aids in the analysis of data, and is freely and conveniently available to install on a wide variety of computer platforms. These scripts are useful for the interpretation of layered velocity models from surface-source downhole seismic data such as deep boreholes and SCPT data. The inputs are the travel-time data and the offset of the source at the surface. The travel-time arrivals for the P- and S-waves must already be picked from the original data. An option in the inversion is to include estimates of the standard deviation of the travel-time picks for a weighted inversion of the velocity profile. The standard deviation of each travel-time pick is defined relative to the standard deviation of the best pick in a profile and is based on the accuracy with which the travel-time measurement could be determined from the seismogram. The analysis of the travel-time data consists of two parts: the identification of layer-interfaces, and the
Contreras Zazueta, M. A.; Perton, M.; Sanchez-Sesma, F. J.; Sánchez-Alvaro, E.
2013-12-01
The seismic hazard assessment of extended developments, such as a dam, a bridge or a pipeline, needs the strong ground motion simulation taking into account the effects of surface geology. In many cases the incoming wave field can be obtained from attenuation relations or simulations for layered media using Discrete Wave Number (DWN). Sometimes there is a need to include in simulations the seismic source as well. A number of methods to solve these problems have been developed. Among them the Finite Element and Finite Difference Methods (FEM and FDM) are generally preferred because of the facility of use. Nevertheless, the analysis of realistic dynamic loading induced by earthquakes requires a thinner mesh of the entire domain to consider high frequencies. Consequently this may imply a high computational cost. The Indirect Boundary Element Method (IBEM) can also be employed. Here it is used to study the response of a site to historical seismic activity. This method is particularly suited to model wave propagation through wide areas as it requires only the meshing of boundaries. Moreover, it is well suited to represent finely the diffraction that can occur on a fault. However, the IBEM has been applied mainly to simple geometrical configurations. In this communication significant refinements of the formulation are presented. Using IBEM we can simulate wave propagation in complex geometrical configurations such as a stratified medium crossed by thin faults or having a complex topography. Two main developments are here described; one integrates the DWN method inside the IBEM in order to represent the Green's functions of stratified media with relatively low computational cost but assuming unbounded parallel flat layers, and the other is the extension of IBEM to deal with multi-regions in contact which allows more versatility with a higher computational cost compared to the first one but still minor to an equivalent FEM formulation. The two approaches are fully
Combined effects of traveling seismic waves and soil nonlinearity on nuclear power plant response
International Nuclear Information System (INIS)
Lee, T.H.; Charman, C.M.
1981-01-01
The effects of ground motion nonuniformity on the seismic input have been actively studied in recent years by considering the passage of traveling seismic waves. These studies gave rise to a new class of soil-structure interaction problems in which the seismic input is modified as a result of the spatial variations of ground motion. The phenomena were usually studied by using the elastic half-space simulation or discrete spring-models for modeling the soil medium. Finite element methods were also used recently on a limited scope. Results obtained from these investigations are often manifested by an attenuation of translational excitation along with an addition of rotational ground motion input. The decrease in structural response resulting from the input loss in the translational component was often insignificant since the response reduction tends to be offset by the effects from rotational input. The traveling wave effects have, so far, been investigated within the framework of linear theory with soil nonlinearity ignored. Conversely, the incorporation of soil nonlinearity in soil-structure interaction analyses has been done without including wave effect. Seismic analyses considering the hysteretic behavior of soil have been performed using highly idealized models for steady-state solution. More elaborate nonlinear seismic models deal with only the strain-dependent soil modulus rather than the transient unloading-reloading type of hysteretic characteristics of soil under a time-function input of earthquake trace. Apparently, the traveling wave effect and soil nonlinearity have been separately treated in the past. The purpose of this paper is to demonstrate that these two major effects can be combined in one model such that the influence of wave passage is reflected through the hysteretic behavior of soil particles, and thereby achieving significant reduction in seismic loads. (orig./RW)
Comparison of seismic response of ordinary and base-isolated structures
International Nuclear Information System (INIS)
Kuroda, T.; Kobatake, M.; Seidensticker, R.W.; Chang, Y.W.
1992-01-01
Seismic isolation is growing rapidly worldwide as a cost-effective and reliable design strategy for a wide range of critical and important facilities (e.g., hospitals, computer centers, etc.) Shimizu Corporation of Japan has a test facility at Tohoku University in Sendai, Japan. The test facility was constructed in 1986 and has two buildings: one is base isolated and the other is conventionally founded. The buildings are full-size, three-story reinforced concrete structures. The dimensions and construction of the superstructures are identical. For the past several years, Shimizu Corporation has installed a number of different isolation systems in the isolated building at the test facility to study the response of base isolation systems to actual earthquake motions. Argonne National Laboratory (ANL) has been deeply involved in the development of seismic isolation for use in nuclear facilities for the past decade. Using the funding and direction of the US Department of Energy (USDOE), ANL has been developing methodology needed to evaluate the usefulness and effectiveness of seismic isolation for advanced liquid metal-cooled reactors (LMRs). This paper compares the seismic responses of ordinary and base-isolated buildings. Earthquake records of significant importance from April 1989 to September 1991, after the installation of bearings have been analyzed. Numerical simulations of the building responses have been performed and correlated with earthquake observation data. It is hoped that the results of this study will provide guidelines for the future use of isolator bearings for mitigation of earthquake damages
Seismic analysis, evaluation and upgrade design for a nuclear facility exhaust stack building
International Nuclear Information System (INIS)
Malik, L.E.; Kabir, A.F.
1991-01-01
This paper reports on an exhaust stack building of a nuclear reactor facility with complex structural configuration that has been analyzed and evaluated for seismic forces. This building was built in the 1950's and had not been designed to resist seismic forces. A very rigorous analysis and evaluation program was implemented to minimize the costly retrofits required to upgrade the building to resist high seismic forces. The seismic evaluations were performed for the building in its as-is configuration, and as modified for several upgrade schemes. Soil-structure-interaction, base mat flexibility and the influence of the nearby reactor building have been considered in the seismic analyses. The rigorous analyses and evaluation enabled limited upgrades to qualify the stack building for the seismic forces
International Nuclear Information System (INIS)
1978-01-01
This report presents the results of a detailed seismic risk analysis of the Nuclear Materials Development Facility (NMDF) operated by Atomics International at Santa Susana, California. The historical seismic record was established after a review of available literature, consultation with operators of local seismic arrays and examination of appropriate seismic data bases including the USGS, California Institute of Technology and NEIS data bases. The resulting seismic record, covering the period 1969 to 1977, was used to identify all possible sources of seismicity that could affect the site. The best estimate curve indicates that the facility will experience 30% g with a return period of 55 years and 60% g with a return period of 750 years
Signal-to-noise ratio application to seismic marker analysis and fracture detection
Xu, Hui-Qun; Gui, Zhi-Xian
2014-03-01
Seismic data with high signal-to-noise ratios (SNRs) are useful in reservoir exploration. To obtain high SNR seismic data, significant effort is required to achieve noise attenuation in seismic data processing, which is costly in materials, and human and financial resources. We introduce a method for improving the SNR of seismic data. The SNR is calculated by using the frequency domain method. Furthermore, we optimize and discuss the critical parameters and calculation procedure. We applied the proposed method on real data and found that the SNR is high in the seismic marker and low in the fracture zone. Consequently, this can be used to extract detailed information about fracture zones that are inferred by structural analysis but not observed in conventional seismic data.
Energy Technology Data Exchange (ETDEWEB)
1978-12-29
This report presents the results of a detailed seismic risk analysis of the Nuclear Materials Development Facility (NMDF) operated by Atomics International at Santa Susana, California. The historical seismic record was established after a review of available literature, consultation with operators of local seismic arrays and examination of appropriate seismic data bases including the USGS, California Institute of Technology and NEIS data bases. The resulting seismic record, covering the period 1969 to 1977, was used to identify all possible sources of seismicity that could affect the site. The best estimate curve indicates that the facility will experience 30% g with a return period of 55 years and 60% g with a return period of 750 years.
Overview of seismic probabilistic risk assessment for structural analysis in nuclear facilities
International Nuclear Information System (INIS)
Reed, J.W.
1989-01-01
Probabilistic Risk Assessment (PRA) for seismic events is currently being performed for nuclear and DOE facilities. The background on seismic PRA is presented along with a basic description of the method. The seismic PRA technique is applicable to other critical facilities besides nuclear plants. The different approaches for obtained structure fragility curves are discussed and their applications to structures and equipment, in general, are addressed. It is concluded that seismic PRA is a useful technique for conducting probability analysis for a wide range of classes of structures and equipment
International Nuclear Information System (INIS)
Farahani, Reza V.; Dessalegn, Tewodros M.; Vaidya, Nishikant R.; Bazan-Zurita, Enrique
2016-01-01
Highlights: • Three dimensional finite element modeling of a Nuclear Power Plant (NPP) building founded on soil is described. • A simplified technique to consider degraded stiffness of concrete members in seismic analysis of NPP buildings is presented. • The effect of subsurface profiles on the seismic response of a NPP building is investigated. - Abstract: This study describes three-dimensional (3-D) finite element (FE) modeling and seismic Soil-Structure Interaction (SSI) analysis of a Nuclear Power Plant (NPP) Diesel Generator Building (DGB) that is founded on soil in degraded concrete stiffness condition. A new technique is presented that uses two horizontal and vertical FE models to consider the concrete stiffness reduction of NPP buildings subjected to orthogonal ground motion excitations, in which appropriate stiffness reduction factors, based on the input motion orientation, are applied. Seismic SSI analysis is performed for each model separately, and dynamic responses are calculated in the three global directions. The results of the analysis for the two FE models are then combined, using the square-root-of-the-sum-of-squares (SRSS) combination rule. A sensitivity analysis is also performed to investigate the subsurface profile effect on the In-Structure (acceleration) Response Spectra (ISRS) of the building when subjected to site-specific Foundation Input Response Spectra (FIRS) that exhibit high spectral amplifications in the high-frequency range. The sensitivity analysis considers three strain-compatible subsurface profiles that represent Lower-Bound (LB), Best-Estimate (BE), and Upper-Bound (UB) conditions at the DGB site. The sensitivity analysis results indicate that the seismic response of the DGB founded on soil highly depends on the subsurface profile; i.e., each of the LB, BE, and UB subsurface profiles can maximize building seismic response when subjected to FIRS that exhibit high spectral amplifications in the high-frequency range
International Nuclear Information System (INIS)
Varma, Amit H.; Seo, Jungil; Coleman, Justin Leigh
2015-01-01
Seismic probabilistic risk assessment (SPRA) methods and approaches at nuclear power plants (NPP) were first developed in the 1970s and aspects of them have matured over time as they were applied and incrementally improved. SPRA provides information on risk and risk insights and allows for some accounting for uncertainty and variability. As a result, SPRA is now used as an important basis for risk-informed decision making for both new and operating NPPs in the US and in an increasing number of countries globally. SPRAs are intended to provide best estimates of the various combinations of structural and equipment failures that can lead to a seismic induced core damage event. However, in some instances the current SPRA approach contains large uncertainties, and potentially masks other important events (for instance, it was not the seismic motions that caused the Fukushima core melt events, but the tsunami ingress into the facility). INL has an advanced SPRA research and development (R&D) activity that will identify areas in the calculation process that contain significant uncertainties. One current area of focus is the use of nonlinear soil-structure interaction (NLSSI) analysis methods to accurately capture: 1) nonlinear soil behavior and 2) gapping and sliding between the NPP and soil. The goal of this study is to compare numerical NLSSI analysis results with recorded earthquake ground motions at Fukushima Daichii (Great Tohuku Earthquake) and evaluate the sources of nonlinearity contributing to the observed reduction in peak acceleration. Comparisons are made using recorded data in the free-field (soil column with no structural influence) and recorded data on the NPP basemat (in-structure response). Results presented in this study should identify areas of focus for future R&D activities with the goal of minimizing uncertainty in SPRA calculations. This is not a validation activity since there are too many sources of uncertainty that a numerical analysis would need
Seismic responses of a pool-type fast reactor with different core support designs
International Nuclear Information System (INIS)
Wu, Ting-shu; Seidensticker, R.W.
1989-01-01
In designing the core support system for a pool-type fast reactor, there are many issues which must be considered in order to achieve an optimum and balanced design. These issues include safety, reliability, as well as costs. Several design options are possible to support the reactor core. Different core support options yield different frequency ranges and responses. Seismic responses of a large pool-type fast reactor incorporated with different core support designs have been investigated. 4 refs., 3 figs
International Nuclear Information System (INIS)
Srinivasan, M.G.; Kot, C.A.; Hsieh, B.J.
1989-01-01
As part of the earthquake investigations at the HDR (Heissdampfreaktor) Test Facility in Kahl/Main, FRG, simulated seismic tests (SHAM) were performed during April--May 1988 on the VKL (Versuchskreislauf) piping system. The purpose of these experiments was to study the behavior of piping subjected to a range of seismic excitation levels including those that exceed design levels manifold and that might induce failure of pipe supports or plasticity in the pipe runs, and to establish seismic margins for piping and pipe supports. Data obtained in the tests are also used to validate analysis methods. Detailed reports on the SHAM experiments are given elsewhere. The objective of this document is to evaluate a subsystem analysis module of the SMACS code. This module is a linear finite-element based program capable of calculating the response of nuclear power plant subsystems subjected to independent multiple-acceleration input excitation. The evaluation is based on a comparison of computational results of simulation of SHAM tests with corresponding test measurements
Multi Canister Overpack (MCO) Handling Machine - Independent Review of Seismic Structural Analysis
International Nuclear Information System (INIS)
SWENSON, C.E.
2000-01-01
The following separate reports and correspondence pertains to the independent review of the seismic analysis. The original analysis was performed by GEC-Alsthom Engineering Systems Limited (GEC-ESL) under subcontract to Foster-Wheeler Environmental Corporation (FWEC) who was the prime integration contractor to the Spent Nuclear Fuel Project for the Multi-Canister Overpack (MCO) Handling Machine (MHM). The original analysis was performed to the Design Basis Earthquake (DBE) response spectra using 5% damping as required in specification, HNF-S-0468 for the 90% Design Report in June 1997. The independent review was performed by Fluor-Daniel (Irvine) under a separate task from their scope as Architect-Engineer of the Canister Storage Building (CSB) in 1997. The comments were issued in April 1998. Later in 1997, the response spectra of the Canister Storage Building (CSB) was revised according to a new soil-structure interaction analysis and accordingly revised the response spectra for the MHM and utilized 7% damping in accordance with American Society of Mechanical Engineers (ASME) NOG-1, ''Rules for Construction of Overhead and Gantry Cranes (Top Running Bridge, Multiple Girder).'' The analysis was re-performed to check critical areas but because manufacturing was underway, designs were not altered unless necessary. FWEC responded to SNF Project correspondence on the review comments in two separate letters enclosed. The dispositions were reviewed and accepted. Attached are supplier source surveillance reports on the procedures and process by the engineering group performing the analysis and structural design. All calculation and analysis results are contained in the MHM Final Design Report which is part of the Vendor Information File 50100. Subsequent to the MHM supplier engineering analysis, there was a separate analyses for nuclear safety accident concerns that used the electronic input data files provided by FWEC/GEC-ESL and are contained in document SNF-6248
Seismic response of a sliding polar crane for a nuclear power plant
International Nuclear Information System (INIS)
Rieck, P.; Schlund, H.
1981-01-01
In the analysis, the bridge crane design is mathematically modeled in the vertical and lateral directions. The bridge crane system is postulated to vibrate in a linear-elastic fashion, until the dynamic reactions occurring at the crane wheel/support interface exceed the available resisting friction, at which time sliding is initiated. Sliding is postulated to continue until the relative velocity of the crane and supporting structure is zero, at which time a linear-elastic vibration mode is again developed. The analysis considers the variation in static and dynamic coefficients of friction and the variation of available friction resistance due to the crane vertical response. The initiation of sliding is modeled as an instantaneous event requiring a redescription of the crane system physical properties and coordinate system. Transfer from the vibrating system to the sliding system is governed by maintaining conservation of energy. Seismic excitation is defined using design floor response spectra appropriate for the crane system location. The design spectra are decomposed into a spectrum of acceleration time history harmonic motions which, when applied to a spectrum of single degree-of-freedom damped spring-mass oscillators, redevelops the original design spectra. The spectrum of acceleration times histories is used as base excitation to the mathematical model. Analytical results include sliding displacements and velocities, number of time sliding occurs, cumulative sliding displacements, and system kinetic and potential energy. A description of the crane system configuration and the development of the effective mass and stiffness values used in the analysis of the vibrating and sliding systems is presented. The equations of motions coupling the horizontal and vertical responses during the vibrating and sliding phases are presented. A discussion evaluating the applicability of the results, and how the results can be used for design, is also presented. (orig.)
International Nuclear Information System (INIS)
Saxena, Navjeev; Paul, D.K.
2012-01-01
Highlights: ► Both the slip and separation of reactor base reduce with increase in embedment. ► The slip and separation become insignificant beyond 1/4 and 1/2 embedment respectively. ► The stresses in reactor reduce significantly upto 1/4 embedment. ► The stress reduction with embedment is more pronounced in case of tensile stresses. ► The modeling of interface is important beyond 1/8 embedment as stresses are underestimated otherwise. - Abstract: The seismic response of nuclear reactor containment building considering the effects of embedment, slip and separation at soil–structure interface requires modeling of the soil, structure and interface altogether. Slip and separation at the interface causes stress redistribution in the soil and the structure around the interface. The embedment changes the dynamic characteristics of the soil–structure system. Consideration of these aspects allows capturing the realistic response of the structure, which has been a research gap and presented here individually as well as taken together. Finite element analysis has been carried out in time domain to attempt the highly nonlinear problem. The study draws important conclusions useful for design of nuclear reactor containment building.
Seismic response of elevated rectangular water tanks considering soil structure interaction
Visuvasam, J.; Simon, J.; Packiaraj, J. S.; Agarwal, R.; Goyal, L.; Dhingra, V.
2017-11-01
The overhead staged water tanks are susceptible for high lateral forces during earthquakes. Due to which, the failure of beam-columns joints, framing elements and toppling of tanks arise. To avoid such failures, they are analyzed and designed for lateral forced induced by devastating earthquakes assuming the base of the structures are fixed and considering functional needs, response reduction, soil types and severity of ground shaking. In this paper, the flexible base was provided as spring stiffness in order to consider the effect of soil properties on the seismic behaviour of water tanks. A linear time history earthquake analysis was performed using SAP2000. Parametric studies have been carried out based on various types of soils such as soft, medium and hard. The soil stiffness values highly influence the time period and base shear of the structure. The ratios of time period of flexible to fixed base and base shear of flexible to fixed base were observed against capacities of water tank and the overall height of the system. The both responses are found to be increased as the flexibility of soil medium decreases
van Veldhuizen, E.J.
2006-01-01
The seismic reflection method for imaging of the earth's interior is an essential part of the exploration and exploitation of hydrocarbon resources. A seismic survey should be designed such that the acquired data leads to a sufficiently accurate subsurface image. The survey geometry analysis method
Fast multifrequency focal beam analysis for 3D seismic acquisition geometry
Wei, W.; Fu, L.; Blacquiere, G.
2012-01-01
A method for the efficient computation of multifrequency focal beams for 3D seismic acquisition geometry analysis has been developed. By computing them for all the frequency components of seismic data, single-frequency focal beams can be extended to multifrequency focal beams. However, this
Seismic hazard analysis for the NTS spent reactor fuel test site
International Nuclear Information System (INIS)
Campbell, K.W.
1980-01-01
An experiment is being directed at the Nevada Test Site to test the feasibility for storage of spent fuel from nuclear reactors in geologic media. As part of this project, an analysis of the earthquake hazard was prepared. This report presents the results of this seismic hazard assessment. Two distinct components of the seismic hazard were addressed: vibratory ground motion and surface displacement
Model Solutions for Performance-Based Seismic Analysis of an Anchored Sheet Pile Quay Wall
Habets, C.J.W.; Peters, D.J.; de Gijt, J.G.; Metrikine, A.; Jonkman, S.N.
2016-01-01
Conventional seismic designs of quay walls in ports are mostly based on pseudo-static analysis. A more advanced alternative is the Performance-Based Design (PBD) method, which evaluates permanent deformations and amounts of (repairable) damage under seismic loading. The aim of this study is to
Directory of Open Access Journals (Sweden)
Ehsan Nikbakht
Full Text Available Precast bridge columns have shown increasing demand over the past few years due to the advantages of such columns when compared against conventional bridge columns, particularly due to the fact that precast bridge columns can be constructed off site and erected in a short period of time. The present study analytically investigates the behaviour of self-centring precast segmental bridge columns under nonlinear-static and pseudo-dynamic loading at different prestressing strand levels. Self-centring segmental columns are composed of prefabricated reinforced concrete segments which are connected by central post-tensioning (PT strands. The present study develops a three dimensional (3D nonlinear finite element model for hybrid post-tensioned precast segmental bridge columns. The model is subjected to constant axial loading and lateral reverse cyclic loading. The lateral force displacement results of the analysed columns show good agreement with the experimental response of the columns. Bonded post-tensioned segmental columns at 25%, 40% and 70% prestressing strand stress levels are analysed and compared with an emulative monolithic conventional column. The columns with a higher initial prestressing strand levels show greater initial stiffness and strength but show higher stiffness reduction at large drifts. In the time-history analysis, the column samples are subjected to different earthquake records to investigate the effect post-tensioning force levels on their lateral seismic response in low and higher seismicity zones. The results indicate that, for low seismicity zones, post-tensioned segmental columns with a higher initial stress level deflect lower lateral peak displacement. However, in higher seismicity zones, applying a high initial stress level should be avoided for precast segmental self-centring columns with low energy dissipation capacity.
Letter report seismic shutdown system failure mode and effect analysis
International Nuclear Information System (INIS)
KECK, R.D.
1999-01-01
The Supply Ventilation System Seismic Shutdown ensures that the 234-52 building supply fans, the dry air process fans and vertical development calciner are shutdown following a seismic event. This evaluates the failure modes and determines the effects of the failure modes
Earthquake response spectra for seismic design of nuclear power plants in the UK
International Nuclear Information System (INIS)
Bommer, Julian J.; Papaspiliou, Myrto; Price, Warren
2011-01-01
Highlights: → Seismic design of UK nuclear power plants usually based on PML response spectra. → We review derivation of PML spectra in terms of earthquake data used and procedure. → The data include errors and represent a small fraction of what is now available. → Seismic design loads in current practice are derived as mean uniform hazard spectra. → The need to capture epistemic uncertainty makes use of single equation indefensible. - Abstract: Earthquake actions for the seismic design of nuclear power plants in the United Kingdom are generally based on spectral shapes anchored to peak ground acceleration (PGA) values obtained from a single predictive equation. Both the spectra and the PGA prediction equation were derived in the 1980s. The technical bases for these formulations of seismic loading are now very dated if compared with the state-of-the-art in this field. Alternative spectral shapes are explored and the options, and the associated benefits and challenges, for generating uniform hazard response spectra instead of fixed shapes anchored to PGA are discussed.
Seismic analysis, evaluation and upgrade design for a DOE exhaust stack building
International Nuclear Information System (INIS)
Malik, L.E.; Maryak, M.E.
1991-01-01
An exhaust stack building of a nuclear reactor facility with complex structural configuration has been analyzed and evaluated and retrofitted for seismic forces. The building was built in the 1950's and had not been designed to resist seismic forces. A rigorous analysis and evaluation program was implemented to minimize costly retrofits required to upgrade the building to resist high seismic forces. Seismic evaluations were performed for the building in its as-is configuration, and as modified for several upgrade schemes. Soil-structure-interaction, basemat flexibility and the influence of the nearby reactor building were considered in rigorous seismic analyses. These analyses and evaluations enabled limited upgrades to qualify the stack building for the seismic forces. Some of the major conclusions of this study are: (1) a phased approach of seismic analyses, utilizing simplified models to evaluate practicable upgrade schemes, and, then incorporating the most suitable scheme in a rigorous model to obtain design forces for upgrades, is an efficient and cost-effective approach for seismic qualification of nuclear facilities to higher seismic criteria; and, (2) finalizing the upgrade of a major nuclear facility is an iterative process, which continues throughout the construction of the upgrades
Experience of a Brazilian A/E in seismic analysis of nuclear structures components
International Nuclear Information System (INIS)
Venancio Filho, F.; Leal, M.R.L.V.; Bevilacqua, L.
1980-01-01
The experience of Promon Engenharia S.A., a Brazilian A/E which participated in the civil and mechanical engineering projects of the first Nuclear Power Plant in Brazil, is presented. In these projects the aspects of input for seismic analysis, seismic analysis in nuclear structures founded on piles, dynamic analysis for airplane crash, and piping analysis had to be faced for the first time in the country. The solution of these problems and some case examples are presented. (Author) [pt
DEFF Research Database (Denmark)
Montazeri, Mahboubeh
2018-01-01
comprises important oil and gas reservoirs. By application of well-established conventional velocity analysis methods and high-quality diffraction imaging techniques, this study aims to increase the resolution and the image quality of the seismic data. In order to analyze seismic wave propagation......-outs and salt delineations, which can be extracted from the diffractions. The potential of diffraction imaging techniques was studied for 2D seismic stacked data from the North Sea. In this approach, the applied plane-wave destruction method was successful in order to suppress the reflections from the stacked....... This improved seismic imaging is demonstrated for a salt structure as well as for Overpressured Shale structures and the Top Chalk of the North Sea....
A guidebook for the operation and maintenance of HANARO seismic monitoring analysis system
Energy Technology Data Exchange (ETDEWEB)
Ryu, Jeong Soo; Yoon, Doo Byung; Kim, Hyung Kyoo
2003-09-01
Systems and structures related to HANARO safety are classified as seismic category I. Since 1995, the seismic monitoring system has been utilized for monitoring an earthquake at the HANARO site. The existing seismic monitoring system consists of field sensors and monitoring panel. The analog-type monitoring system with magnetic tape recorder is out-of-date model. In addition, the disadvantage of the existing system is that it does not include signal-analyzing equipment. Therefore, we have improved the analog seismic monitoring system into a new digital Seismic Monitoring Analysis System(SMAS) that can offer precise and detail information of the earthquake signals. This newly developed SMAS is operating at the HANARO instrument room to acquire and analyze the signal of an earthquake. This document is a guidebook for the operation and maintenance of the SMAS. The first chapter gives an outline of the SMAS. The second chapter describes functional capability and specification of the hardware. Chapters 3 and 4 describe starting procedure of the SMAS and how to operate the seismic monitoring program, respectively. Chapter 5 illustrates the seismic analysis algorithm used in the SMAS. The way of operating the seismic analysis program is described in chapter 6. Chapter 7 illustrates the calibration procedure for data acquisition module. Chapter 8 describes the symptoms of common malfunctions and its countermeasure suited to the occasions.
Seismic response in archaeological areas: the case-histories of Rome
Donati, Stefano; Funiciello, Renato; Rovelli, Antonio
1999-03-01
Rome is affected by earthquakes associated to three different seismogenic districts: the Central Apennines area, the Colli Albani volcanic area and the Roman area. The major effects were exclusively due to Apennine seismicity and reached in some cases felt intensities up to VII-VIII degree (MCS scale). The predominant role in the damage distribution seems to be played by the local geological conditions. The historical centre of the city is characterized by the presence of two geomorphologic domains: the alluvial plain of Tiber river and the topographic relieves of Roman Hills, where tradition indicates the first site of the city foundation. In particular, the right river side is characterized by the outcropping of the regional bedrock along the Monte Mario-Gianicolo ridge, while the eastern relieves are the remnants of the Sabatini and Albani volcanic plateau, deeply eroded by the Tiber river and its tributaries during the last glacial low-stand (Würm). These domains are characterized by a large difference in seismic response, due to the high impedance contrast between Holocene coarse deposits filling the Tiber Valley and sedimentary and volcanic Plio-Pleistocene units. Seismic damage observed in 150 monuments of downtown Rome was indicating a significant concentration on alluvial recent deposits. This result was confirmed by the geographical distribution of conservation and retrofitting activities subsequent to main earthquakes, mostly related to local geological conditions. The cases of Marcus Aurelius' Column and Colosseum confirmed the influence of the Holocene alluvial network in local seismic response. During 2500 years of history, the monuments of Rome have `memorized' the seismic effects of historical earthquakes. In some cases, the integration of historical and geological research and macroseismic observations may provide original and useful indications to seismologists to define the seismic response of the city. Local site effects represent a serious
Non linear seismic analysis of charge/discharge machine
International Nuclear Information System (INIS)
Dostal, M.; Trbojevic, V.M.; Nobile, M.
1987-01-01
The main conclusions of the seismic analysis of the Latina CDM are: i. The charge machine has been demonstrated to be capable of withstanding the effects of a 0.1 g earthquake. Stresses and displacements were all within allowable limits and the stability criteria were fully satisfied for all positions of the cross-travel bogie on the gantry. ii. Movements due to loss of friction between the cross-travel bogie wheels and the rail was found to be small, i.e. less than 2 mm for all cases considered. The modes of rocking of the fixed and hinged legs preclude any possibility of excessive movement between the long travel bogie wheels and the rail. iii. The non-linear analysis incorporating contact and friction has given more realistic results than any of the linear verification analyses. The method of analysis indicates that even the larger structures can be efficiently solved on a mini computer for a long forcing input (16 s). (orig.)
Synchrosqueezing-based Transform and its Application in Seismic Data Analysis
Directory of Open Access Journals (Sweden)
Saman Gholtashi
2015-10-01
Full Text Available Seismic waves are non-stationary due to its propagation through the earth. Time-frequency transforms are suitable tools for analyzing non-stationary seismic signals. Spectral decomposition can reveal the non-stationary characteristics which cannot be easily observed in the time or frequency representation alone. Various types of spectral decomposition methods have been introduced by some researchers. Conventional spectral decompositions have some restrictions such as Heisenberg uncertainty principle and cross-terms which limit their applications in signal analysis. In this paper, synchrosqueezingbased transforms were used to overcome the mentioned restrictions; also, as an application of this new high resolution time-frequency analysis method, it was applied to random noise removal and the detection of low-frequency shadows in seismic data. The efficiency of this method is evaluated by applying it to both synthetic and real seismic data. The results show that the mentioned transform is a proper tool for seismic data processing and interpretation.
UMTS rapid response real-time seismic networks: implementation and strategies at INGV
Govoni, A.; Margheriti, L.; Moretti, M.; Lauciani, V.; Sensale, G.; Bucci, A.; Criscuoli, F.
2015-12-01
Universal Mobile Telecommunications System (UMTS) and its evolutions are nowadays the most affordable and widespread data communication infrastructure available almost world wide. Moreover the always growing cellular phone market is pushing the development of new devices with higher performances and lower power consumption. All these characteristics make UMTS really useful for the implementation of an "easy to deploy" temporary real-time seismic station. Despite these remarkable features, there are many drawbacks that must be properly taken in account to effectively transmit the seismic data: Internet security, signal and service availability, power consumption. - Internet security: exposing seismological data services and seismic stations to the Internet is dangerous, attack prone and can lead to downtimes in the services, so we setup a dedicated Virtual Private Network (VPN) service to protect all the connected devices. - Signal and service availability: while for temporary experiment a carefull planning and an accurate site selection can minimize the problem, this is not always the case with rapid response networks. Moreover, as with any other leased line, the availability of the UMTS service during a seismic crisis is basically unpredictable. Nowadays in Italy during a major national emergency a Committee of the Italian Civil Defense ensures unified management and coordination of emergency activities. Inside it the telecom companies are committed to give support to the crisis management improving the standards in their communication networks. - Power consumption: it is at least of the order of that of the seismic station and, being related to data flow and signal quality is largely unpredictable. While the most secure option consists in adding a second independent solar power supply to the seismic station, this is not always a very convenient solution since it doubles the cost and doubles the equipment on site. We found that an acceptable trade-off is to add an
Directory of Open Access Journals (Sweden)
Nikos Nanos
2013-01-01
Full Text Available This paper identifies the effects of infill wall existence and arrangement in the seismic response of frame structures utilising the global structural damage index after Park/Ang (GDIPA and the maximum interstorey drift ratio (MISDR to express structural seismic response. Five different infill wall topologies of a 10-storey frame structure have been selected and analysed presenting an improved damage distribution model for infill wall bearing frames, hence promoting the use of nonstructural elements as a means of improving frame structural seismic behaviour and highlighting important aspects of structural response, demonstrating the suitability of such element implementation beyond their intended architectural scope.
Directory of Open Access Journals (Sweden)
Daogang Lu
2015-01-01
Full Text Available Huge water storage tank on the top of many buildings may affect the safety of the structure caused by fluid-structure interaction (FSI under the earthquake. AP1000 passive containment cooling system water storage tank (PCCWST placed at the top of shield building is a key component to ensure the safety of nuclear facilities. Under seismic loading, water will impact the wall of PCCWST, which may pose a threat to the integrity of the shield building. In the present study, an FE model of AP1000 shield building is built for the modal and transient seismic analysis considering the FSI. Six different water levels in PCCWST were discussed by comparing the modal frequency, seismic acceleration response