WorldWideScience

Sample records for bridge piers

  1. Hysteretic behavior of prestressed concrete bridge pier with fiber model.

    Science.gov (United States)

    Wang, Hui-li; Feng, Guang-qi; Qin, Si-feng

    2014-01-01

    The hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier were researched. The effects of the prestressed tendon ratio, the longitudinal reinforcement ratio, and the stirrup reinforcement ratio on the hysteretic behavior and seismic characteristics of the prestressed concrete bridge pier have been obtained with the fiber model analysis method. The analysis show some results about the prestressed concrete bridge pier. Firstly, greater prestressed tendon ratio and more longitudinal reinforcement can lead to more obvious pier's hysteresis loop "pinching effect," smaller residual displacement, and lower energy dissipation capacity. Secondly, the greater the stirrup reinforcement ratio is, the greater the hysteresis loop area is. That also means that bridge piers will have better ductility and stronger shear capacity. The results of the research will provide a theoretical basis for the hysteretic behavior analysis of the prestressed concrete pier. PMID:24578635

  2. Impact of bridge pier on the stability of ice jam

    Institute of Scientific and Technical Information of China (English)

    王军; 施发义; 陈胖胖

    2015-01-01

    River ice jam is one of the most important issues in rivers in cold regions during winter time. With the extra solid boundary due to the ice cover, the flow condition under ice-covered conditions is completely different from that of a open channel flow. The presence of bridge piers will further change the velocity field around the bridge piers. As a consequence, the formation and the accumulation of ice jams in the vicinity of the bridge pier will be affected. On the other side, the formation of an ice jam around the piers can cause extra turbulence to reduce the stability of a river bridge. The present study focuses on the stress analysis of the ice jam in the vicinity of a bridge pier. By developing a governing equation for describing the equilibrium state of an ice jam, the stability of the ice jam around bridge piers is analyzed and determined. As seen from the field data in literature, the stability estimations of an ice jam around bridge piers determined by the present method agree well with the field observations. Therefore, the proposed approach can be used for the prediction of the formation of ice jams around bridge piers.

  3. Modelling the Flow Structure in Local Scour Around Bridge Pier

    Directory of Open Access Journals (Sweden)

    Usman Ghani

    2014-04-01

    Full Text Available Bridge pier scouring is an important issue of any bridge design work. If it is not taken into account properly, then results will be disastrous. A number of bridges have failed due to clear water local scouring of piers. This research paper presents a numerical model study in which an attempt has been made to explore the flow variables which exist in and around a scoured bridge pier. A finite volume based model of bridge pier was developed using 3D (Three Dimensional numerical code FLUENT and GAMBIT. After validation process, different discharge values were considered and its impact on three dimensional characteristics of flow such as stream-wise velocities on longitudinal and transverse sections, turbulance circulation cells, and boundary shear stresses was investigated. It was observed that increasing the discharge results in more turbulance around the pier on its downstream side and turbulence properties are intensified in such a situation. However, the primary velocities on the downstream side remain almost unchanged. The results have been presented in the form of contours, vector of primary velocities and x-y plots of bed shear stresses. This study can be used for enhanced understanding of flow features and improvement of formulae for prediction of scour holes around piers

  4. SCOUR MITIGATION AT BRIDGE PIERS USING SACRIFICIAL PILES

    Institute of Scientific and Technical Information of China (English)

    M. Anisul HAQUE; Md. Munsur RAHMAN; G.M. Tarekul ISLAM; M. Asad HUSSAIN

    2007-01-01

    To mitigate scour around bridge piers, sacrificial piles are economic method where natural processes are involved. The arrangement should be such that scoured materials from the sacrificial piles should have enough volume to fill the scour hole created upstream of the pier in such a way that sediments are trapped inside the scour hole. This concept differs from earlier study made with sacrificial piles that mainly deals to reduce the strength of horseshoe vortex. To determine the effect of sacrificial piles for scour mitigation, alternative arrangements of piles were tested in front of a rectangular pier under clear-water condition and found that when the group of piles is placed at a distance of twice the projected width of the pier, for which percentage of blockage of the pier width is 60%, the scour volume can be reduced upto 61% while the maximum scour depth can be reduced upto 50%.

  5. THE EXPERIMENT OF THE COMPLEX INSPECTION OF THE RAILROAD BRIDGE PIER

    Directory of Open Access Journals (Sweden)

    B. M. Usachenko

    2010-03-01

    Full Text Available The procedure and results of a visual inspection and vibrosonic diagnostics of the railroad bridge pier are described. The spatial model of the pier with an arrangement of large cracks is presented.

  6. Centrifuge modeling of rocking-isolated inelastic RC bridge piers

    OpenAIRE

    Loli, Marianna; Knappett, Jonathan A; Brown, Michael J.; Anastasopoulos, Ioannis; GAZETAS, George

    2014-01-01

    Experimental proof is provided of an unconventional seismic design concept, which is based on deliberately underdesigning shallow foundations to promote intense rocking oscillations and thereby to dramatically improve the seismic resilience of structures. Termed rocking isolation, this new seismic design philosophy is investigated through a series of dynamic centrifuge experiments on properly scaled models of a modern reinforced concrete (RC) bridge pier. The experimental method reproduces th...

  7. Hollow bridge-pier properties for response spectrum analysis

    OpenAIRE

    TAUCER, FABIO; PAULOTTO Carlo; AYALA Gustavo

    2010-01-01

    The present paper proposes equivalent stiffness and energy dissipation properties of reinforced concrete hollow bridge piers to be used in the context of response spectrum performance based assessment and design. The work is carried out by performing parametric numerical analysis using a 2D fibre model calibrated against experimental results and by varying the longitudinal steel reinforcement ratio, height over width ratio, normalised axial force, level of confinement and concrete class of a ...

  8. Rigid-Plastic Dynamic Response of Reinforced Concrete Bridge Pier Impacted by Automobile

    Institute of Scientific and Technical Information of China (English)

    ZHENG Xiaoning; DIAO Bo; YE Yinghua

    2006-01-01

    Bridge piers are impacted by autos sometimes.The pier usually has not been destroyed after once impact by auto.But there are few research on damage which will affect pier's capability,and most relative studies have focused the problems on piers impacted by vessels.The methods involve mainly sutra experience theory,numerical analysis,and experimental method.Owing to the complicacy of the bridge pier impacted by a vessel,there are few research derived with the sutra mechanics model and the piers impacted by autos.The dynamic response is studied here under the assumption of the rigid-plastic small-deformation for the pier impacted by auto.According to the Parkes beam model,the rigid-plastic theoretical solution is deduced.The final deformation is calculated by a practical example for the pier impacted by auto.

  9. The impact of bridge pier on ice jam evolution – an experimental study

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2016-03-01

    Full Text Available The ice jam in a river can significantly change the flow field in winter and early spring. The presence of bridge piers further complicates the hydraulic process by interacting between the ice jam and bridge piers. Using the data collected from experiments in a laboratory flume, the evolution of an ice jam around bridge piers having three different diameters has been investigated in this study. Compared to results without-pier, it was found that the formation of an ice jam in the downstream of bridge pier is faster than that in the upstream. The thickness distribution of the ice jam shows clearly different characteristics in front and behind of bridge piers at different stages of the ice jam.

  10. Experimental study on the width of the turbulent area around bridge pier

    Institute of Scientific and Technical Information of China (English)

    ZHUANG Yuan; LIU Zu-yuan

    2007-01-01

    At present, the method of calculating the turbulent flow width around the bridge pier is not given in the "Standard for Inland River Navigation" (GB50139-2004) in China, and the bridge designer usually increases the bridge span in order to ensure the navigation safety, which increases both of the structural design difficulty and the project investments. Therefore, it is extremely essential to give a research on the turbulent flow width around the bridge pier. Through the experiments of the fixed bed and the mobile bed, the factors influencing the turbulent flow width around the bridge pier have been analyzed, such as the approaching flow speed, the water depth, the angles between the bridge pier and the flow direction, the sizes of bridge pier, the shapes of the bridge pier, and the scouring around the bridge pier, etc. Through applying the dimension analytic method to the measured data, the formula of calculating the turbulent flow width around the bridge pier is then inferred.

  11. Ship collisions against wind turbines, quays and bridge piers

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup

    2013-01-01

    Analytical procedures are presented for analysis of the external dynamics of ship collisions against bottom supported flexible as well as rigid offshore structures such as wind turbine structures, quays and bridge piers. Based on the principles of conservation of momentum and energy algebraic...... plays an important role for reduction of the structural damage. For gravity based foundations it is shown that provided some limited foundation displacements can be allowed then the requirements to the shear sliding force capacity can be reduced significantly. © 2013 Taylor & Francis Group....

  12. Numerical Hybrid Simulation Modeling Verification for a Curved 3-Pier Bridge (Investigation of Combined Actions on Reinforced Concrete Bridge Piers (CABER Project

    Directory of Open Access Journals (Sweden)

    Adel Abdelnaby

    2013-06-01

    Full Text Available Reinforced concrete bridge piers are subjected to complex loading conditions under earthquake ground motions. Bridge geometric irregularities and asymmetries result in combined actions imposed on the piers as a combination of displacements and rotations in all six degrees of freedom at the pier-deck juncture. Existing analytical tools have proven their inadequacy in representing the actual behavior of piers under these combined actions, particularly in their inelastic range. The objective of this investigation is to develop a fundamental understanding of the effects of these combined actions on the performance of RC piers and the resulting system response. This paper describes a part of the CABER project that verifies the numerical hybrid simulation of the curved bridge. In this part two models were introduced, a whole model and a sub-structured hybrid model. The whole model was established using the Zeus-NL analysis platform, which is capable of performing inelastic nonlinear response history analysis of the whole curved bridge. The hybrid model was divided into three modules which comprised the deck, left and right piers, and the middle pier of the bridge. The three modules were modeled by Zeus-NL as a static analysis module interface. The simulation coordinator (SimCor software was utilized to communicate between these modules using a Pseudo-Dynamic time integration scheme. Results obtained from both models were compared and conclusions were drawn.

  13. Catastrophic model for stability analysis of high pile-column bridge pier

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to the engineering features of higher pile-column bridge pier in mountainous area, a clamped beam mechanical model was set up by synthetically analyzing the higher pile-column bridge pier buckling mechanism. Based on the catastrophe theory, the cusp catastrophe model of higher pile-column bridge pier was established by the determination of its potential function and bifurcation set equation, the necessary instability conditions of high pile-column bridge pier were deduced, and the determination method for column-buckling and lateral displacement of high pile-column bridge pier was derived. The comparison between the experimental and calculated results show that the calculated curves agree with testing curves and the method is reasonable and effective.

  14. The effect of circular bridge piers with different inclination angles toward downstream on scour

    Indian Academy of Sciences (India)

    Mohammad Vaghef; Masoud Ghodsian; Saeid Salimi

    2016-01-01

    A fundamental principle in the safe design of bridge piers is to estimate maximum scour depth. As such, many researchers devoted their efforts to study the phenomenon of scour around bridge piers and to present relationships to estimate maximum scour depth. In the current research, scour around circular bridge piers with two different diameters and different inclination angles toward downstream has been investigated experimentally under clear water and different discharges. The obtained results revealed that increase in the inclination angle leads to a significant decrease in the scour depth, dimensions of sediment ridge and scour hole. Moreover, by comparing the data obtained from vertical bridge pier and well-known relationships, a relationship having the most agreement with the results was selected and modified to estimate equilibrium scour depth around inclined piers.

  15. Mathematical Modeling of Local Scour at Slender and Wide Bridge Piers

    Directory of Open Access Journals (Sweden)

    Youssef I. Hafez

    2016-01-01

    Full Text Available Most existing equations for predicting local scour at bridge piers suffer from overprediction of the scour depths which results in higher foundation costs. To tackle this problem, a mathematical model for predicting bridge pier scour is developed herein based on an energy balance theory. The present study equation was compared to commonly used bridge scour equations using scour field data in USA. The developed equation has several advantages among which we have the following: it adds to the understanding of the physics of bridge pier scour, is valid for slender and wide piers, does not suffer from overprediction of scour depths, addresses clear water and live bed scour, and includes the effects of various characteristics of the bed material such as specific gravity (or density, porosity, size, and angle of repose. In addition, the developed equation accounts for the debris effect and aids in the design of scour mitigation methods such as collars, side bars, slots, and pier protective piles.

  16. Seismic Behavior of Posttensioned Concrete Bridge Piers with External Viscoelastic Dampers

    Directory of Open Access Journals (Sweden)

    Anxin Guo

    2016-01-01

    Full Text Available This paper investigates the seismic performance of posttensioned concrete piers with external viscoelastic dampers to improve the energy dissipation capacity of this type of structure. An installation scheme for viscoelastic dampers on bridge piers is proposed, and the mechanical models of the damper are analyzed according to the installation scheme. By attaching the viscoelastic dampers to the posttensioned bridge piers, the analytical model of the hybrid system is established using the OpenSees finite element analysis package. Cyclic behavior and time history analyses are conducted on a posttensioned bridge with and without viscoelastic dampers using the established finite element model. The analysis results indicate that the viscoelastic dampers can effectively improve the seismic performance of the bridge structures with posttensioned piers.

  17. Seismic bridge pier analysis for pile foundation by force and displacement based approaches

    OpenAIRE

    Singh NP.R.; Vinayak Hemant Kumar

    2015-01-01

    Seismic analysis of bridge pier supported on pile foundation requires consideration of soil-pile-structure (kinematic and inertial) interactions. This paper presents the design forces generated for bridge piers with varying height and constant diameter for medium and soft soils in earthquake probability zones considering contribution of soil-pile-structure interactions by developed analytical approaches. The results have shown that the difference in base sh...

  18. Study on Repaired Earthquake-Damaged Bridge Piers under Seismic Load

    Directory of Open Access Journals (Sweden)

    Jun Deng

    2015-01-01

    Full Text Available The concrete bridge pier damaged during earthquakes need be repaired to meet the design standards. Steel tube as a traditional material or FRP as a novel material has become popular to repair the damaged reinforced concrete (RC bridge piers. In this paper, experimental and finite element (FE studies are employed to analyze the confinement effectiveness of the different repair materials. The FE method was used to calculate the hysteretic behavior of three predamaged circle RC bridge piers repaired with steel tube, basalt fiber reinforced polymer (BFRP, and carbon fiber reinforced polymer (CFRP, respectively. Meanwhile, the repaired predamaged circle concrete bridge piers were tested by pseudo-static cyclic loading to study the seismic behavior and evaluate the confinement effectiveness of the different repair materials and techniques. The FE analysis and experimental results showed that the repaired piers had similar hysteretic curves with the original specimens and all the three repair techniques can restore the seismic performance of the earthquake-damaged piers. Steel tube jacketing can significantly improve the lateral stiffness and peak load of the damaged pier, while the BFRP and CFRP sheets cannot improve these properties due to their thin thickness.

  19. Pushover analysis of the seismic capacity of reinforced concrete double-column bridge piers

    Directory of Open Access Journals (Sweden)

    WANG Hongwei

    2013-02-01

    Full Text Available This article deacribes the basic principle and implementation steps of the Pushover analysis method.By a numerical example,RC double-column piers with different lateral force distribution pattern,different heights and different reinforcement ratio were analyzed.The results show that the analysis results for lower piers of simple supported beam bridges are approximately identical under different lateral force distribution,while with the increase of pier height and longitudinal ratio of reinforcement,the displacement ductility factor is reduced.

  20. Cyclic Load Responses of GFRP-Strengthened Hollow Rectangular Bridge Piers

    OpenAIRE

    Junfeng Jia; Qiang Han; Zigang Xu; Dongjie Zhang

    2014-01-01

    This study investigated the seismic behavior of glass fiber reinforced polymer (GFRP) strengthened hollow rectangular bridge piers. Cyclic testing of reinforced concrete (RC) piers retrofitted with GFRP was carried out under constant axial loading and lateral bending. The failure characteristics, flexural ductility, dissipated energy, and hysteretic behaviors, were analyzed based on experimental results. A simplified GFRP-confined concrete model is developed by considering effective strength ...

  1. Multi-objective optimization design of bridge piers with hybrid heuristic algorithms

    Institute of Scientific and Technical Information of China (English)

    Francisco J. MARTINEZ-MARTIN; Femando GONZALEZ-VIDOSA; Antonio HOSPITALER; Victor YEPES

    2012-01-01

    This paper describes one approach to the design of reinforced concrete (RC) bridge piers,using a three-hybrid multiobjective simulated annealing (SA) algorithm with a neighborhood move based on the mutation operator from the genetic algorithms (GAs),namely MOSAMO1,MOSAMO2 and MOSAMO3.The procedure is applied to three objective functions:the economic cost,the reinforcing steel congestion and the embedded CO2 emissions.Additional results for a random walk and a descent local search multi-objective algorithm are presented.The evaluation of solutions follows the Spanish Code for structural concrete.The methodology was applied to a typical bridge pier of 23,97 m in height.This example involved 110 design variables.Results indicate that algorithm MOSAMO2 outperforms other algorithms regarding the definition of Pareto fronts.Further,the proposed procedure will help structural engineers to enhance their bridge pier designs.

  2. Realistic modelling of the effects of asynchronous motion at the base of bridge piers

    CERN Document Server

    Romanelli, F; Vaccari, F

    2002-01-01

    Frequently long-span bridges provide deep valley crossings, which require special consideration due to the possibility of local amplification of the ground motion as a consequence of topographical irregularities and local soil conditions. This does in fact cause locally enhanced seismic input with the possibility for the bridge piers to respond asynchronously. This introduces special design requirements so that possible out-of-phase ground displacements and the associated large relative displacements of adjacent piers can be accommodated without excessive damage. Assessment of the local variability of the ground motion due to local lateral heterogeneities and to attenuation properties is thus crucial toward the realistic definition of the asynchronous motion at the base of the bridge piers. We illustrate the work done in the framework of a large international cooperation to assess the importance of non-synchronous seismic excitation of long structures. To accomplish this task we compute complete synthetic acc...

  3. Prediction of Scour Depth around Bridge Piers using Adaptive Neuro-Fuzzy Inference Systems (ANFIS)

    Science.gov (United States)

    Valyrakis, Manousos; Zhang, Hanqing

    2014-05-01

    Earth's surface is continuously shaped due to the action of geophysical flows. Erosion due to the flow of water in river systems has been identified as a key problem in preserving ecological health of river systems but also a threat to our built environment and critical infrastructure, worldwide. As an example, it has been estimated that a major reason for bridge failure is due to scour. Even though the flow past bridge piers has been investigated both experimentally and numerically, and the mechanisms of scouring are relatively understood, there still lacks a tool that can offer fast and reliable predictions. Most of the existing formulas for prediction of bridge pier scour depth are empirical in nature, based on a limited range of data or for piers of specific shape. In this work, the application of a Machine Learning model that has been successfully employed in Water Engineering, namely an Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate the scour depth around bridge piers. In particular, various complexity architectures are sequentially built, in order to identify the optimal for scour depth predictions, using appropriate training and validation subsets obtained from the USGS database (and pre-processed to remove incomplete records). The model has five variables, namely the effective pier width (b), the approach velocity (v), the approach depth (y), the mean grain diameter (D50) and the skew to flow. Simulations are conducted with data groups (bed material type, pier type and shape) and different number of input variables, to produce reduced complexity and easily interpretable models. Analysis and comparison of the results indicate that the developed ANFIS model has high accuracy and outstanding generalization ability for prediction of scour parameters. The effective pier width (as opposed to skew to flow) is amongst the most relevant input parameters for the estimation.

  4. Experimental research and finite element analysis of bridge piers failed in flexure-shear modes

    Institute of Scientific and Technical Information of China (English)

    Sun Zhiguo; Si Bingjun; Wang Dongsheng; Guo Xun

    2008-01-01

    In recent earthquakes,a large number of reinforced concrete (RC) bridges were severely damaged due to mixed flexure-shear failure modes of the bridge piers.An integrated experimental and finite element (FE) analysis study is described in this paper to study the seismic performance of the bridge piers that failed in flexure-shear modes.In the first part,a nonlinear cyclic loading test on six RC bridge piers with circular cross sections is carried out experimentally.The damage states,ductility and energy dissipation parameters,stiffness degradation and shear strength of the piers are studied and compared with each other.The experimental results suggest that all the piers exhibit stable flexural response at displacement ductilities up to four before exhibiting brittle shear failure.The ultimate performance of the piers is dominated by shear capacity due to significant shear cracking,and in some cases,rupturing of spiral bars.In the second part,modeling approaches describing the hysteretic behavior of the piers are investigated by using ANSYS software.A set of models with different parameters is selected and evaluated through comparison with experimental results.The influences of the shear retention coefficients between concrete cracks,the Bauschinger effect in longitudinal reinforcement,the bond-slip relationship between the longitudinal reinforcement and the concrete and the concrete failure surface on the simulated hysteretie curves are discussed.Then,a modified analysis model is presented and its accuracy is verified by comparing the simulated results with experimental ones.This research uses models available in commercial FE codes and is intended for researchers and engineers interested in using ANSYS software to predict the hysteretic behavior of reinforced concrete structures.

  5. Determine of velocity field with PIV and CFD during the flow around of bridge piers

    Directory of Open Access Journals (Sweden)

    Picka D.

    2013-04-01

    Full Text Available The article describes the processing of specific junior research FAST-J-11-51/1456 which dealt with physical and CFD of the velocity field during the flow around of bridge piers. Physical modelling has been carried out in Laboratory of water management research in Institute of Water Structures in Brno University of Technology – Faculty of Civil Engineering. To measure of the velocity field in profile of bridge piers were used laser measuring method PIV (Particle Image Velocimetry. The results of PIV served as a basis for comparing experimental data with CFD results of this type of flow in the commercial software ANSYS CFX.

  6. A study on ship impacting a flexible crashworthy device for protecting bridge pier

    Directory of Open Access Journals (Sweden)

    Yang Liming

    2015-01-01

    Full Text Available As the accident of a vessel impacting a bridge pier will cause serious disaster, such as destroyed bridge, sinking ship and polluting environment, the technology and method to protect bridge pier from ship collision have been widely investigated recently. Due to the huge kinetic energy of large-tonnage ship and the short time duration in the collision, the studies involve impact mechanics. A developed flexible crashworthy device has been developed to protect bridges, which consists of an outer steel-periphery, an inner steel-periphery and the rubber coating SWRCs(soft elements installed between them. When the SWRC crashworthy device is installed, the collision duration under low impact force is prolonged due to its high compliance, which results in the ship having enough time to turn its navigation direction and most of the remainder kinetic energy being carried off by the turned away ship. Consequently, both impact forces on the ship and on the bridge pier decrease markedly. This is the key reason as to why the SWRC crashworthy device can avoid the destruction of both the bridge and the ship. Based on our results of theoretical studies and numerical simulations, the present paper will propose an experiment-adopted a real ship to impact a flexible crashworthy device. The collision test has been performed 12 times with different speed, carrying capacity, and impact angle of the ship. After the experiments, the ship, flexible crashworthy device and the pier are not damaged. The experiments show that the flexible crashworthy device can turn away the impact ship, so that the ship moves along the outer part of the device, which reduces the ship impact force on the bridge pier obviously. It not only protects bridges but also avoids the damage to ships.

  7. Cyclic Load Responses of GFRP-Strengthened Hollow Rectangular Bridge Piers

    Directory of Open Access Journals (Sweden)

    Junfeng Jia

    2014-01-01

    Full Text Available This study investigated the seismic behavior of glass fiber reinforced polymer (GFRP strengthened hollow rectangular bridge piers. Cyclic testing of reinforced concrete (RC piers retrofitted with GFRP was carried out under constant axial loading and lateral bending. The failure characteristics, flexural ductility, dissipated energy, and hysteretic behaviors, were analyzed based on experimental results. A simplified GFRP-confined concrete model is developed by considering effective strength coefficient and area distribution ratio of GFRP sheets. The results indicate that the failure modes and damage region would be changed and the ductility and dissipated energy of the GFRP-strengthened hollow rectangular bridge piers were improved greatly but not much improvement for the lateral load capacity. The analytical results of the force-displacement hysteretic loops based on the GFRP-confined concrete model developed in this paper agreed well with the experimental data.

  8. Effects of seismic devices on transverse responses of piers in the Sutong Bridge

    Science.gov (United States)

    Shen, Xing; Camara, Alfredo; Ye, Aijun

    2015-12-01

    The Sutong Bridge in China opened to traffic in 2008, and is an arterial connection between the cities of Nantong and Suzhou. It is a cable-stayed bridge with a main span of 1,088 m. Due to a tight construction schedule and lack of suitable seismic devices at the time, fixed supports were installed between the piers and the girder in the transverse direction. As a result, significant transverse seismic forces could occur in the piers and foundations, especially during a return period of a 2500-year earthquake. Therefore, the piers, foundations and fixed bearings had to be designed extraordinarily strong. However, when larger earthquakes occur, the bearings, piers and foundations are still vulnerable. The recent rapid developments in seismic technology and the performance-based design approach offer a better opportunity to optimize the transverse seismic design for the Sutong Bridge piers. The optimized design can be applied to the Sutong Bridge (as a retrofit), as well as other bridges. Seismic design alternatives utilizing viscous fluid dampers (VFD), or friction pendulum sliding bearings (FPSB), or transverse yielding metallic dampers (TYMD) are thoroughly studied in this work, and the results are compared with those from the current condition with fixed transverse supports and a hypothetical condition in which only sliding bearings are provided on top of the piers (the girder can move "freely" in the transverse direction during the earthquake, except for frictional forces of the sliding bearings). Parametric analyses were performed to optimize the design of these proposed seismic devices. From the comparison of the peak bridge responses in these configurations, it was found that both VFD and TYMD are very effective in the reduction of transverse seismic forces in piers, while at the same time keeping the relative transverse displacements between piers and the box girder within acceptable limits. However, compared to VFD, TYMD do not interact with the

  9. Seismic bridge pier analysis for pile foundation by force and displacement based approaches

    Directory of Open Access Journals (Sweden)

    Singh NP.R.

    2015-01-01

    Full Text Available Seismic analysis of bridge pier supported on pile foundation requires consideration of soil-pile-structure (kinematic and inertial interactions. This paper presents the design forces generated for bridge piers with varying height and constant diameter for medium and soft soils in earthquake probability zones considering contribution of soil-pile-structure interactions by developed analytical approaches. The results have shown that the difference in base shear demand between force based and displacement based approach and that between capacity spectrum and displacement based method in general decreases with the increase in slenderness ratio of the pier. The base shear demand by non-linear time history analysis has been found to be much higher compared to that by other methods. The relationship between height and pier cross-section has been developed for different soils and seismic zones such that the base shear demands by force based and displacement based method are of the same order. The overall value of the slenderness ratio works out to be such that failure of the pile shall be as a short column for both medium and soft soil.

  10. A Novel Structural Assessment Technique to Prevent Damaged FRP-Wrapped Concrete Bridge Piers from Collapse

    OpenAIRE

    Buyukozturk, Oral; Yu, Tzu-Yang

    2009-01-01

    Repairing deteriorated concrete bridge piers using externally wrapped fiber reinforced polymer (FRP) composites have been proven as an effective approach. This technique has also been applied to low-rise building structures. Failures in FRP-wrapped concrete structures may occur by flexural failures of critical sections or by debonding of FRP plate from the concrete substrate. Debonding in the FRP/adhesive/concrete interface region may cause a significant decrease in member capacity leading to...

  11. Stability Analysis of Long-Span Continuous Rigid Frame Bridge with Thin-Wall Pier

    Institute of Scientific and Technical Information of China (English)

    HE Bo; SHI Ya-nan; ZHU Hong-ping; GUO Wen-zeng; CHEN Yong

    2008-01-01

    During cantilever cast in construction of high-pier and large-span continuous rigid frame bridges, structural stability in the longest cantilevered stage is very important. Based on a practical design case of a large-span continuous rigid frame bridge in Wuhan, the longest span stability coefficient is calculated with linear-buckling and nonlinear-buckling methods, respectively. The influences of both geometrical nonlinearity and the dual nonlinearity of material and geometry are considered. Numerical results indicate that the nonlinear solution is necessary to stability analysis because linear buckling loads axe much higher than those of nonlinear buckling. Thus, the edge fiber yield criterion is more convenient and faster than ultimate loading criterion when estimating nonlinear stability of structure, and can be used easily in the initial engineering design.

  12. Seismic response of bridge pier on rigid caisson foundation in soil stratum

    Institute of Scientific and Technical Information of China (English)

    C. Tsigginos; N. Gerolymos; D. Assimaki; G. Gazetas

    2008-01-01

    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.

  13. Experimental and numerical investigation of the effect of different shapes of collars on the reduction of scour around a single bridge pier.

    Directory of Open Access Journals (Sweden)

    Afshin Jahangirzadeh

    Full Text Available The scour phenomenon around bridge piers causes great quantities of damages annually all over the world. Collars are considered as one of the substantial methods for reducing the depth and volume of scour around bridge piers. In this study, the experimental and numerical methods are used to investigate two different shapes of collars, i.e, rectangular and circular, in terms of reducing scour around a single bridge pier. The experiments were conducted in hydraulic laboratory at university of Malaya. The scour around the bridge pier and collars was simulated numerically using a three-dimensional, CFD model namely SSIIM 2.0, to verify the application of the model. The results indicated that although, both types of collars provides a considerable decrease in the depth of the scour, the rectangular collar, decreases scour depth around the pier by 79 percent, and has better performance compared to the circular collar. Furthermore, it was observed that using collars under the stream's bed, resulted in the most reduction in the scour depth around the pier. The results also show the SSIIM 2.0 model could simulate the scour phenomenon around a single bridge pier and collars with sufficient accuracy. Using the experimental and numerical results, two new equations were developed to predict the scour depth around a bridge pier exposed to circular and rectangular collars.

  14. Assessment of Soil-Structure Interaction in Seismic Bridge Pier Analysis Using Force and Displacement Based Approaches

    Science.gov (United States)

    Singh, R. N. P.; Vinayak, Hemant Kumar

    2015-11-01

    The seismic analysis carried out assuming foundation to be perfectly rigid and bonded to the soil underneath is far from truth and therefore, the soil-structure interaction effect on the dynamic behavior of the bridge pier should be considered. The assessment of soil-structure effect on the design force generated has been estimated using Force based, Capacity Spectrum and Direct Displacement based methods considering fixed and flexible foundations. For this purpose a single cantilever bridge pier of constant diameter with varying heights has been considered for the analysis in different type of soils and earthquake zones. The study has revealed that soil-Structure Interaction index is negative in some cases, especially in soft soil, implying base shear demand being greater than that of fixed base contrary to the traditional views.

  15. Assessment of Soil-Structure Interaction in Seismic Bridge Pier Analysis Using Force and Displacement Based Approaches

    Directory of Open Access Journals (Sweden)

    Singh R N P

    2015-11-01

    Full Text Available The seismic analysis carried out assuming foundation to be perfectly rigid and bonded to the soil underneath is far from truth and therefore, the soil-structure interaction effect on the dynamic behavior of the bridge pier should be considered. The assessment of soil-structure effect on the design force generated has been estimated using Force based, Capacity Spectrum and Direct Displacement based methods considering fixed and flexible foundations. For this purpose a single cantilever bridge pier of constant diameter with varying heights has been considered for the analysis in different type of soils and earthquake zones. The study has revealed that soil-Structure Interaction index is negative in some cases, especially in soft soil, implying base shear demand being greater than that of fixed base contrary to the traditional views.

  16. Investigation of chloride induced corrosion of bridge pier and life-cycle repair cost analysis using fiber reinforced polymer composites

    Science.gov (United States)

    Dhakal, Dinesh

    Bridges are the long term investment of the highway agencies. To maintain the required service level throughout the life of a bridge, a series of maintenance, repair, and rehabilitation (MRℝ) works can be performed. To investigate the corrosion deterioration and maintenance and repair practices in the bridge pier columns constructed in chloride-laden environment, a questionnaire survey was conducted within the 50 state Departments of Transportation (DOTs). Based on the survey data, two corrosion deterioration phases were identified. They were corrosion crack initiation phase and corrosion propagation phase. The data showed that the mean corrosion crack initiation phase for bridge pier column having cover of 50 mm, 75 mm, and 100 mm was 18.9 years, 20.3 years, and 22.5 years, respectively. The corrosion propagation phase starts after the corrosion crack initiation. The corrosion propagation is defined in a single term, corrosion damage rate, measured as percentage of area damaged due to corrosion cracking, spalling, and delamination. From the survey, the corrosion damage rate was found 2.23% and 2.10% in the bridge pier columns exposed to deicing salt water and exposed to tidal splash/spray, respectively. For this study, two different corrosion damage rates were proposed before and after the repair criteria for minor damage repair as practiced by DOTs. This study also presents the collected data regarding the corrosion effectiveness of using sealers and coatings, cathodic protection, corrosion inhibitors, carbon fiber/epoxy composites, and glass fiber/epoxy composites as maintenance and repair technique. In this study, the cost-effectiveness of wrapping carbon fiber/epoxy composites and glass fiber/epoxy composites in bridge pier columns constructed in a chloride-laden environment was investigated by conducting life-cycle cost analysis. As a repair work, externally bonded two layer of carbon fiber/epoxy and glass fiber/epoxy composites were installed by wet

  17. Nonlinear Stability Analysis of Long-Span Continuous Rigid Frame Bridge with Thin-Wall High Piers

    Institute of Scientific and Technical Information of China (English)

    Li Li; Peng Yuancheng; Long Xiaohong; Liao Ping

    2005-01-01

    By utilizing the current finite element program ANSYS, two types of finite element models (FEM), the beam model (BM) and shell model (SM), are established for the nonlinear stability analysis of a practical rigid frame bridge-Longtanhe Great Bridge. In these analyses, geometrical and material nonlinearities are simultaneously taken into account. For geometrical nonlinearity, updated Lagrangian formulations are adopted to derive the tangent stiffness matrix. In order to simulate the nonlinear behavior of the plastic hinge of the piers, the multi-lines spring element COMBIN39 is used in the SM while the bilinear rotational spring element COMBIN40 is employed in the BM. Numerical calculations show that satisfying results can be obtained in the stability analysis of the bridge when the double coupling nonlinearity effects are considered. In addition, the conclusion is significant for practical engineering.

  18. Investigation on brittle fracture of high bridge pier by Hyogoken-Nanbu earthquake; Hyogoken nanbu jishin ni yori chukokan ramen kyokyaku ni shojita zeisei hakai o gen`in chosa

    Energy Technology Data Exchange (ETDEWEB)

    Eto, O.; Mihara, T. [Kubota Corp., Osaka (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan). Faculty of Engineering

    1998-04-21

    During the Hyogoken-nanbu earthquake, Ikuta Bridge for railway was not broken but severely damaged. The steel bridge piers were fractured. The Ikuta Bridge was constructed with two steel rigid frames at its ends and two reinforced concrete rigid frames at its center with a three-span 50 m long steel girder in 1967. During the earthquake, the steel pier at the western end was moved in 1 m toward north, and the movable support and pier at the western end were fractured. At the eastern end, the fixed support and the pier were not damaged, but the RC pier of the support base was fractured. To clarify the cause of damages and the fracture mechanism, dynamic response analysis, static elasto-plastic analysis, observations of fracture faces, and material tests were carried out. As a result, it was considered that the brittle fracture of centrifugal cast steel bridge piers of Ikuta Bridge was caused by the horizontal impact exceeding the bearing force for fractures over the piers after the initial fracture of movable support at the western end. From the observations of fracture faces, peeling tests of paints, and hardness tests, it was suggested that the fractures of cast steel piers were initially generated at the yield stress level. 3 refs., 16 figs., 6 tabs.

  19. Earthquake Response Analysis of High Pier T -beam Bridge in Mountainous Region%山区高墩梁桥抗震分析

    Institute of Scientific and Technical Information of China (English)

    杨相展

    2012-01-01

    A seven spans of 40m T - beam high pier bridge is studied in this paper. By utilizing the finite ele- ment software, a three - dimensional mechanics model is established. Based on the model, seismic behavior of T - beam high pier bridge, in which various support links between pier and beam are considered, is investigated by u- sing the nonlinear time history method. The results indicate that structural earthquake -resistance performance can be improved by using seismic isolation bearing.%以一座7—40mT梁高架桥为研究对象,建立了三维空间模型,采用非线性时程分析方法,分析了不同墩梁连接方式的山区高墩T梁桥的抗震性能,计算结果表明:采用铅芯隔震橡胶支座可以提高桥梁的抗震性能。

  20. 桥墩防船撞设施研究%Study on Anti-collision Facilities of Bridge Pier against Ships

    Institute of Scientific and Technical Information of China (English)

    侯勇; 侯刚

    2011-01-01

    Combining with the design of Guanzhou River special bridge anti-collision facilities, this paper analyzes the basic requirement of anti-collision facilities of piers, carries out comparison on performance of common anti-collision facilities in China as well as differences in economy of diverse anti-collision facilities, develops proper calculation method and briefs design of steel sheath for major piers of this bridge : It consists of multi-chamber sheath similar to the structure of a ship and rubber buffer layers between the sheath and piers that has the merits of energy absorption and less space occupation.%文章结合官洲河特大桥防撞设施设计实例,分析了桥墩防撞设施的基本要求,对我国常用的防撞设施作了性能比较,并对不同防撞设施进行了经济比较,提出了适用的计算方法,同时介绍了该桥主墩钢套箱设计情况:主要由类似船舶结构的多室构造套箱和套箱与桥墩间的橡胶弹性缓冲层构成,具有吸能好、占空间少等优点。

  1. 桥墩防车辆撞击研究综述%Review of Studies on Vehicle Anti-collision on Bridge Piers

    Institute of Scientific and Technical Information of China (English)

    陈林; 肖岩

    2012-01-01

    Along with the growth in freeway mileage, the amount and capacity of vehicles, bridges as traffic hinges are facing with a more and more serious risk, namely vehicle collision with pier. To date, the design specifications in many countries, such as China, US, Britain, etc. , have included some provisions addressing vehicle collision with bridge piers. However, the review finds that (1) most of the provisions adopt a simple static design method, without considering the parameters of pier, such as stiffness and ductility; (2) some of the origins of the provisions are rather vague, and others merely use foreign standard for reference, thus the effectiveness of these provisions is doubtable; (3 ) there is no provision addressing the prerequisite of the anti-collision design of piers in Chinese standard, and so designers should decide by themselves whether or not the collision force should be considered. This negative provision would probably result in a negligent of the collision effect in practice. In view of these, the studies on vehicle anti-collision on bridge piers from the aspects of protective structure around the bridge pier and the pier itself were reviewed. Some major problems and proposals were presented.%由于高速公路里程、机动车数量及其运载能力的持续增加,作为交通运输枢纽的桥梁,正面临着一种越来越严重的威胁,即车辆对桥墩的撞击.目前中、美、英等国的设计规范均对桥墩防撞设计作出了相关规定,然而分析发现:各国规范仍大都采用简单的静力设计法,没有考虑桥墩刚度、延性等参数对撞击力的影响;一些规范的理论来源非常含糊,而另一些则只是简单地参考别国规范,其有效性值得怀疑.我国规范未对桥墩防车辆撞击设计的具体条件作出明确规定,设计人员须自行判断该桥墩是否需要考虑车辆撞击力,这种消极的规定往往造成实际工程中对车辆撞击作用的忽视.有鉴于此,从

  2. Discussion on Method for Prefabricating Cushion Cap of Bridge Pier in Water%桥梁水中墩承台预制施工方法探讨

    Institute of Scientific and Technical Information of China (English)

    郑机

    2011-01-01

    Research purposes: As there are lots of big rivers in China, the construction technology of the bridge pier in water has been widely used for the municipal projects, highway projects and railway projects. In construction of bridges in China, the open excavation foundation pit, ordinary - support foundation pit, building artificial island and surrounding wall, and building surrounding wall with concrete pile, steel plate pile, steel tube pile, single wall steel, double wall steel, thin wall concrete, boxed cofferdam, pouring jacket and continuous wall are used for the cushion cap. The discussion is made on the construction technology of the cushion cap of the bridge pier in water to cut the construction cost and promote the progress of the construction technology of bridge on the premise of ensuring the construction safety, quality and process.Research conclusions: The high - order prefabricating technology for the bridge pier in water has been used in foreign country, but not be used in China. From the analysis and research it is concluded the high - order prefabricating technology for the bridge pier in water is available with the features of good universal property, advanced technology, safety, reliability and and good economical efficiency. After further optimization and tests, the high - order prefabricating technology for the bridge pier in water can be widely used.%我国大江大河众多,市政、公路、铁路建设中,广泛使用桥梁水中墩施工技术.在国内桥梁施工中,承台一般采用明挖基坑、一般支护基坑、筑岛围堰、混凝土桩围堰、钢板桩围堰、钢管桩围堰、单壁钢围堰、双壁钢围堰、薄壁混凝土围堰、吊箱围堰、套箱围堰、地下连续墙围堰等就地现浇施工方法.通过探索桥梁水中墩承台施工新技术,在安全、质量、进度得到保证的情况下,减低工程成本,促进桥梁建设技术进步.研究结论:桥梁水中墩承台高位预制施工技术在国

  3. 新型桥墩防撞装置研究%Research on New Type of Bridge Pier Anti-collision Device

    Institute of Scientific and Technical Information of China (English)

    侯跃鹏

    2016-01-01

    In recent years, ship-bridge collision accidents occur frequently .The increasing number of ship col-lision accidents has put forward a new urgent requirement to the study of anti-ship collision .The current situation of ship-bridge collision research was introduced , using LS-DYNA software , established a ship impacting bridge pier computational model , and conducted the numerical simulation of bridge pier with and without anti-collision device respectively , compared the results of the evolution of the impact force , displacement deformation and energy ab-sorption , and carried out the detailed analysis of the result , obtained the corresponding conclusions about the effect of anti-collision.The research results have certain reference significance to the design of anti-collision device of bridge structure in the future .%近年来船舶撞击桥墩的事故频繁发生,日益增多的船撞桥事故对桥梁防船撞研究提出了新的迫切要求。介绍了船桥碰撞研究现状,运用LS-DYNA软件建立了船舶撞击桥墩的计算模型。分别对无防护装置和有防护装置进行了数值模拟,对比其碰撞力演变、桥墩位移变形和能量吸收等结果;并对其进行了详细分析,得到了关于防撞效果的相应结论。研究结果对今后桥梁结构的防撞装置设计有一定的参考意义。

  4. CFRP加固受损桥墩的抗震性能试验研究%Experimental Research on Seismic Performance of Strengthening Damaged Bridge Pier with CFRP

    Institute of Scientific and Technical Information of China (English)

    吴刚; 丁明波

    2013-01-01

    以某城市立交工程为背景,建立桥墩缩尺模型,完成CFRP加固前后模型墩的拟静力破坏试验,分析研究模型墩加固前后的滞回曲线、骨架曲线、刚度退化曲线和能力耗散系数曲线.研究表明,采用CFRP加固受损桥墩,可有效恢复桥墩抗震性能,甚至得到提高,加固效果明显.%The experimental research is based on an interchange engineering of a city, where two scale models of bridge pier are built. Pseudo-static test is conducted to damage the scale model and strengthened the model with CFRP. The hysteretic curve, skeleton curve, stiffness degradation curve and energy dissipation coefficient curve of the scale model and strengthened model are analyzed. The experimental research shows that the seismic performance of bridge pier model can be recovered under the CFRP strengthening technology, and the capacity even can be enhanced The strengthening effect is obvious.

  5. 矮墩桥梁的抗震设计与计算%Seismic Design and Calculation of Short Pier Bridge

    Institute of Scientific and Technical Information of China (English)

    宿其连

    2014-01-01

    以3×30m连续梁桥为例,在桥墩高度为5m时,建立该桥的三维有限元模型。桥梁主梁和桥墩通过弹性连接来模拟桥梁支座,考虑土和桩基的相互作用,通过土弹簧来模拟,并在桥梁横向和纵向两个方向输入地震作用。采用反应谱法进行分析。%This is a study on the building of the three-dimensional finiteelement model. It takes the continuous beam bridge which is 3í30m in length and 5m in height as an example. The bridge bearings are supposed to be constructed by elastic connect-ion of the bridge girder and pier. To take the bridge as a whole, the interaction between soil and pile foundation should be put into consideration. Soil spring is used to simulate the model, and the seismic effect is input in horizontal and vertical direction of the bridge. The data are analyzed by response spectrum method.

  6. Three Dimensional Analysis of the Final Design of Pier Extensions and West Guide Wall to Mitigate Local Scour Risk at the BNSF Railroad Bridge Downstream of the Prado Dam Supplemental Report

    Energy Technology Data Exchange (ETDEWEB)

    Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sinha, N. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Kerenyi, K. [Turner-Fairbank Highway Research Center, McLean, VA (United States); Sharp, Jeremy [U.S. Army Corps of Engineers, Vicksburg, MI (United States), Coastal and Hydraulics Lab

    2016-06-01

    This report is a supplement to a previous report [ref] covering optimization of wedge shaped pier extensions to streamline large bluff body piers as a local scour countermeasure for the Burlington Northern and Santa Fe (BNSF) Railroad Bridge over the Santa Ana River downstream of Prado Dam in Riverside County, CA. The optimized design was tested in a 1/30 scale physical model at U.S. Army Engineer Research and Development Center (ERDC) in Vicksburg, MS, and the optimized design was used as the base for the construction design. Constructability issues having to do with both materials and site conditions including access underneath the BNSF bridge yielded a construction design that required making the pier extensions wider and either moving the western curve of the west guide wall upstream or changing its geometry.

  7. 高架桥薄壁空心高墩施工%Construction Organizational Design for High Hollow Thin-wall Pier of Viaduct Bridge

    Institute of Scientific and Technical Information of China (English)

    冯世敏

    2014-01-01

    PJ-200 Cantilever formwork ( climbing formwork ) and big steel formwork lifted with tower crane ( turnover formwork construction) have been adopted for the construction of high hollow thin-wall pier of Hewei Bridge at Km:253+353 of Lechang-Guangzhou Expressway, which has achieved good economic benefits.%乐昌至广州高速公路K253+353河尾大桥薄壁空心高墩施工组织设计采用PJ-200悬臂模板(即爬模施工)和塔吊提升大块钢模的方法施工(即翻模施工)相结合的方式,取得了较好的经济效益。

  8. The Influence of High Piers with Horizontal Temperature Difference on CWR on the Continuous Rigid Frame Bridge%高墩水平温差对连续刚构桥上无缝线路的影响

    Institute of Scientific and Technical Information of China (English)

    张亚爽; 胡志鹏; 马旭峰; 王平

    2014-01-01

    An engineering project of the continuous rigid frame bridge is selected in this paper in order to study the influence of high piers under the condition of horizontal temperature difference on continuous welded rail on the bridge. Based on the principle of the interaction between bridge and track, a track-bridge-pier integration finite element model is established to analyze the stress and deformation of continuous welded rail on the large-span bridge with high piers under the condition of various longitudinal and transverse temperature differences. Study results show that the continuous welded rail on the continuous rigid frame bridge is affected greatly by the longitudinal temperature difference of high piers, and the force acting on the continuous welded rail increases with the increasing of the longitudinal temperature difference of high piers. The regularity of the continuous welded rail is influenced by the transverse temperature difference of piers. When the transverse temperature difference of piers is more than certain limit value, long wave irregularity of the continuous welded rail will exceed the limit. Therefore, it's suggested that the influence of high piers under the condition of longitudinal and transverse temperature difference on continuous welded rail on the continuous rigid frame bridge should be considered in the design and check-calculation of continuous welded rail on the bridge.%为研究高墩水平温差对桥上无缝线路的影响,选取某高墩大跨连续刚构桥工程实例,基于梁轨相互作用原理,建立线桥墩一体化有限元模型,分析在水平纵向和横向温差作用下高墩大跨桥上无缝线路受力变形情况。结果表明:高墩纵向温差对连续刚构桥上无缝线路纵向受力影响较大,随着桥墩纵向温差的增大,桥上无缝线路受力逐渐增大;桥墩横向温差影响桥上无缝线路平顺性,当桥墩横向温差超过一定的限值时,连续刚构桥上

  9. Analysis of Anti-Seismic Design of Long-Span Continuous Rigid-Frame Railway Bridge with High-Rise Piers%铁路高墩大跨度连续刚构桥抗震设计分析

    Institute of Scientific and Technical Information of China (English)

    卢三平

    2015-01-01

    为保证在罕遇地震下桥梁结构满足规范要求,以主跨120 m的高墩大跨连续刚构桥———云南万拉木特大桥为例,运用M IDAS Civil建立连续刚构桥空间有限元模型,对其进行动力特性及罕遇地震作用下的非线性时程分析,并优化延性抗震设计。分析结果表明:桥梁振型以梁墩的横向振动为主,第1阶横向侧弯的自振周期为1.697 s ,全桥最大振幅出现在桥墩墩顶位置。在罕遇地震(50年超越概率为2%)作用下,中跨墩顶、底受力较大,均已进入屈服,但其弯矩均小于钢筋极限弯矩,桥梁满足“大震不倒”抗震性能目标。对塑性铰区进行优化,将墩底以上3m空心与实体分界位置处截面外层部分主筋弯折,形成最不利塑性铰区域;加强墩顶、底塑性铰区域横向约束钢筋布置,提高墩柱延性。%To ensure that the bridge structure could meet the code requirements under the ac‐tion of a rare earthquake ,the Wanlamu Bridge ,a long‐span continuous rigid‐fame bridge with a main span of 120 m and with high‐rise piers in Yunnan province ,was cited as an example for the study .The MIDAS Civil software was used to set up the finite element model of the continuous rigid‐frame bridge ,to examine the dynamic performance of the bridge ,carry out non‐linear time history analysis and optimize the ductile anti‐seismic design .The results of the analysis indicate that the transverse vibration of the piers is the dominant vibration mode of the bridge ,the natural vibration period of the 1st order transverse lateral bending is 1 .697s ,and the maximum vibration amplitude of the whole bridge was found at pier tops .Under the action of rare earthquakes (the exceedance probability in 50 years is 2% ) , the top and base of middle span piers bear heavier loads ,which has been identified in yielding period ;however ,the bending moment of the middle span piers is less than the

  10. Cause Analysis and Disposal Advice on Crack in Huzhun Second-tier Bridge Pier Tray and Top Hat%呼准二线桥墩托盘顶帽裂缝成因分析及处置意见

    Institute of Scientific and Technical Information of China (English)

    徐华鑫

    2014-01-01

    With No.1 bridge pier in the inner Mongolia Coal railway as background , based on top hat crack dis-tribution in bridge pier tray , digital resiliometer was used for detecting concrete strength in crack densely-strewn area, supersonic detector was used for detecting width and depth of crack , and finally ANSYS is applied for pre-stress analysis .Through analysis on crack distribution and results from ANSYS , some advices are put forward to strengthen the No .1 bridge pier .%以内蒙古地方铁路呼准运煤专用线1号桥墩为背景,根据桥墩顶帽托盘的裂缝分布情况,采用数显回弹仪测试裂缝分布严重区域的混凝土强度,用超声波检测仪对裂缝的宽度和深度做了检测,通过有限元软件ANSYS对出现裂缝的区域做了应力分析。根据现场观察到的裂缝分布情况和有限元分析的结果,提出了对1号墩的加固和处置意见。

  11. Seismic response analysis for pier of continuous gird bridge in passenger railway%客运专线连续梁桥墩地震反应分析

    Institute of Scientific and Technical Information of China (English)

    王存国

    2012-01-01

    This paper studies continuous bridge on a span of (60 + 100 +60)m, the finite element software was used to build the whole model that considering pile-soil-stucture interaction. The spectrum response method and the time-history analysis were adopted to calculate the seismic response. The result were compared in detail and the influence of foundation stiffness for seismic response was analyzed, the result shows that the foundation stiffness has more influence on seismic response of pier.%以(60+100+60)m连续梁为研究对象,用有限元软件建立了该桥考虑桩土效应作用的全桥模型,采用反应谱法及时程分析法分析结构地震响应,并对其结果进行比较,同时分析基础刚度对地震反应的影响,结果表明基础刚度对桥墩地震反应影响较大。

  12. Influence of hydrodynamic pressure on seismic response of bridge piers in deep water%动水压力作用对深水桥墩地震响应的影响

    Institute of Scientific and Technical Information of China (English)

    黄信; 李忠献

    2011-01-01

    Hydrodynamic pressure on bridge piers would occur during water-pier interaction under earthquakes.The influence of hydrodynamic pressure on the seismic response of bridge piers is studied.Hydrodynamic pressure formula is established using both the Morison equation method and the radiation wave theory.The influence of hydrodynamic pressure on the seismic response of bridge piers is studied and the two methods are compared.The influence of hydrodynamic pressure on the seismic response of a pier with pile foundation is analyzed with consideration of soilstructure interaction and bidirectional earthquake action.The results indicate that the dynamic characteristics of pier changed and the seismic response is augmented because of the hydrodynamic pressure effect, and this effect becomes more significant with the increase of the relative water depth.For piers with wider upstream face, the influence of hydrodynamic pressure from the Morisen equation is obviously larger than that from the radiation wave theory.The action of hydrodynamic pressure decreases if the soil-structure interaction is considered, but the influence of hydrodynamic pressure cannot be ignored.The influence of hydrodynamic pressure will be enhanced under bidirectional earthquake action.In conclusion, the influence of hydrodynamic pressure on the seismic response of piers needs to be considered in seismic analysis of large bridge piers in deep water.%地震激励下水与桥墩的相互作用会对桥墩产生动水压力,本文研究动水压力作用对深水桥墩地震响应的影响,对提高深水桥墩长大桥梁的抗震安全性尤为重要.分别采用Morison方程和辐射波浪理论,建立了动水压力计算方法,分析了动水压力作用对桥墩地震响应的影响,并比较了两种方法计算的动水压力对桥墩地震响应影响的差异;分析了考虑土一结构相互作用时以及双向地震作用下动水压力作用对桩基桥墩地震响应的影响.研究表明:

  13. 基于子模型法的斜拉桥塔梁墩固结段局部分析%Analysis on Fixed Tower-Beam-Pier Part of Cable-Stayed Bridge Based on Sub-Model Method

    Institute of Scientific and Technical Information of China (English)

    宋军; 周建庭; 陈增顺

    2013-01-01

    在对大跨径斜拉桥整体结构有限元分析的基础上,应用子模型法对斜拉桥塔梁墩固结位置进行了有限元结构受力分析,计算了4种不同工况下结构的应力应变状态.研究表明:子模型法可以更为精确有效地计算斜拉桥塔梁墩固结处的应力分布情况,计算结果可作为大跨径斜拉桥塔梁墩固结处局部设计和施工的参考依据.%Based on the finite element analysis of the whole structure of the long-span cable-stayed bridge,the sub-model method was applied to do finite element structural stress analysis of the pylon-girder-pier joint,and the stress and strain of the structure were calculated in four different working conditions.The research shows that sub-model method can calculate the stress distribution of the pylon-girder-pier joint more accurately and the calculating results can be considered as the reference to the design and construction of fixed tower-pier-beam part of the long-span cable-stayed bridge.

  14. 大跨径斜拉桥塔墩梁固结处空间受力分析%Analysis of Spatial Mechanical Behavior of Pylon, Girder and Pier Rigid Fixity Structures of Long-span Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    黄力; 刘志权; 石雪飞

    2012-01-01

    The Huaihe and Five Rivers Bridge of Anhui is hybrid girder cable-stayed bridge, with span arrangement (246 +125) m and single tower double cable planes tower pier beam consolidation system. Midas/ Civil is used to establish a space truss model for the overall analysis to determine the most unfavorable parts of the tower-pier-beam loading conditions. With the large general-purpose finite element software ANSYS, three-dimensional solid model tower-pier-beam consolidation is established, which provides scientific and theoretical basis for the design and construction.%安徽五河淮河桥大桥为混合梁斜拉桥,跨径布置为(246+125)m,为独塔双索面塔墩梁固结体系.利用Midas/Civil建立空间杆系模型进行整体静力分析,确定塔墩梁部位四种最不利荷载工况,得到其活载影响线加载位置和荷载大小.再利用大型通用有限元软件ANSYS建立塔墩梁固结处三维实体模型进行受力分析,为设计与施工提供科学理论依据.

  15. 钢筋混凝土双柱桥墩抗震能力Pushover分析%Pushover analysis of the seismic capacity of reinforced concrete double-column bridge piers

    Institute of Scientific and Technical Information of China (English)

    王红伟; 刘建新

    2013-01-01

    介绍了Pushover分析方法的基本原理及实施步骤.通过一个算例分析,针对不同侧向力分布模式、不同高度、不同纵向配筋率的双柱桥墩进行Pushover分析.结果表明:对于普通简支梁双柱墩,高度比较低,不同侧向力加载模式对Pushover分析结果影响不大,随着桥墩高度的增加,位移延性系数降低,桥墩延性随着纵向配筋率的提高而降低.%This article deacribes the basic principle and implementation steps of the Pushover analysis method. By a numerical example, RC double-column piers with different lateral force distribution pattern, different heights and different reinforcement ratio were analyzed. The results show that the analysis results for lower piers of simple supported beam bridges are approximately identical under different lateral force distribution, while with the increase of pier height and longitudinal ratio of reinforcement, the displacement ductility factor is reduced.

  16. 驶经桥墩船体非定常水动力相互作用数值预报%Numerical prediction of the unsteady hydrodynamic interaction between a ship and a bridge pier

    Institute of Scientific and Technical Information of China (English)

    张晨曦; 邹早建; 王化明

    2012-01-01

    应用CFD软件对船舶通过桥区时的船体-桥墩水动力相互作用进行数值研究,通过使用动网格技术及UDF进行船舶运动过程中的网格更新,对船舶沿直线航线匀速驶经桥墩时的非定常粘性流场进行数值模拟,对桥墩诱导的船体非定常水动力进行数值预报,其中假设船舶航速很小,因而自由面兴波的影响可以忽略.以一艘集装箱船和一个垂直柱体桥墩模型为例,选取不同的船体-桥墩横向距离进行了数值计算,得到了作用在船体上的横向力和转首力矩时历曲线,分析了船体-桥墩横向距离对船体非定常水动力的影响.%A general-purpose CFD software is applied to study the hydrodynamic interaction between a bridge pier and a ship passing through the bridge area along a straight course at constant speed. By using the dynamic mesh technique and UDF to update the mesh, the unsteady viscous flow around the ship is numerically simulated and the unsteady hydrodynamic force on the hull induced by the pier is predicted. The ship speed is assumed to be small, so that the effect of free surface elevation is negligible. Numerical calculations are performed for a container ship and a vertical column as a simplified pier model at various distances between the ship and the pier. The time histories of the lateral force and yaw moment are obtained. The influence of the distance between the ship and the pier is analyzed.

  17. 碳纤维增强复合材料修复震后玻璃纤维增强复合材料管钢筋混凝土桥墩柱抗震性能试验%EXPERIMENTAL INVESTIGATION ON THE SEISMIC BEHAVIOR OF SEVERE EARTHQUAKE-DAMAGED GFRP TUBED REINFORCED CONCRETE BRIDGE PIERS REPAIRED WITH WRAPPED CFRP SHEETS

    Institute of Scientific and Technical Information of China (English)

    王清湘; 王轩

    2011-01-01

    In order to investigate the seismic behavior of earthquake-damaged GFRP (Glass Fiber Reinforced Polymer) tubed reinforced concrete bridge piers repaired with wrapped CFRP (carbon fiber reinforced polymer or plastics) sheets, four GFRP tubed RC bridge piers repaired with wrapped CFRP sheets were tested under repeat low cyclic load. The hysteresis loops, skeleton curves, ductility and energy dissipation ability of the repaired RC bridge piers were compared with those of the original piers. Research show that the bearing capacity and ductility of the repaired bridge piers can be restored or even improved.%为了研究碳纤维增强复合材料(CFRP)修复震后玻璃纤维增强复合材料(GFRP)管混凝土桥墩柱的抗震性能,对4根CFRP修复震后破坏GFRP管混凝土桥墩柱进行拟静力试验,对比修复后钢筋混凝土桥墩柱与原型桥墩柱的滞回曲线、骨架曲线、延性和耗能能力。试验结果表明,修复后的墩柱承载力和延性指标均能得到较好的恢复甚至提高。

  18. Analysis of Influence Factors of Structure Stability for SingleColumn Pier Continuous Girder Bridge%独柱墩连续梁桥的稳定影响因素分析

    Institute of Scientific and Technical Information of China (English)

    吴玉华; 蔡若红; 杨育人

    2011-01-01

    Taking the case of Jinhua-Taizhou section of zhuyong highway, 23 simulation models of single-column pier continuous girder bridge were established by MIDAS finite element program. The major factors which would affect the stability of curved girder bridge, such as the radius of curvature, the length of bridge, the space between two bearings and the offset distance of bearing placed on the single-column pier etc. The results show that the radius of curvature has great effect on the negative counter-force of bearing. The bearing separation is likely to occur when the radius of curvature is less than 200 m and the length of bridge is greater than 100 m. That the appropriate layout offset distance of bearing and enlargement of the space between bearings can assure lower possibility of bearing separation and enhance the ability of bridge performance against overturning.%以诸永高速金华台州段工程为例,采用MIDAS有限元分析程序,构建了23座独柱墩连续箱梁桥的仿真模型,系统分析和总结了影响弯梁桥稳定性的主要影响因素,如曲率半径、桥梁长度、联端支座间距、独柱墩支座预设偏心等.结果表明:桥梁曲率半径对支座负反力影响很大,当曲率半径小于200 m,桥梁长度大于100 m时较易发生支座脱空现象;增大联端支座间距,合理设置支座偏心距,可减小支座出现脱空的可能性,提高桥梁的抗倾覆能力.

  19. Shaft Blasting Control Technology of Subway Near Bridge Pier%临近桥墩地铁竖井爆破控制技术

    Institute of Scientific and Technical Information of China (English)

    贾晓旭; 赵玉成

    2016-01-01

    taking project between Xia Yuan station ~Nan Gang station of Guangzhou metro line 13 first period en-gineering construction (fish bead to like neck ridge section ) as the background ,carried out blasting control design of the minimum distance of the shaft to the nearest building as the safety distance . The paper carried out blasting isolation de-sign mainly from the blasting parameters ,hole arrangement ,charge structure ,packing ,initiation and initiation network etc. At the same time ,grouting reinforcement on the basis of the nearest overpass bored pile so that reduced the founda-tion affected by vibration. Stetted the blasting safety protection system , prevent the surrounding buildings and vehicle pedestrian injuries from fly rock. Monitor the bridge pier vibration speed ,which is controlled within the 2cm/s during the construction period. It shows that the design of shock absorption and vibration reduction technology can meet the require-ments of design and engineering ,which provides a reference for similar blasting construction control technology .%以广州市轨道交通十三号线首期工程(鱼珠至象颈岭段)施工五标夏园站~南岗站区间临时竖井工程为背景,进行了以竖井到最近建筑物最小距离为安全控制距离的爆破控制设计。主要从爆破参数、布孔方式、装药结构、填塞方式、起爆方式和起爆网络等方面进行爆破减震设计,同时对最近立交桥钻孔灌注桩基础进行注浆加固,减小基础所受震动影响。设置爆破安全防护系统,防止爆破飞石对周边建筑物和车辆行人造成伤害。施工期间监测立交桥桥墩振速,均控制在允许振速范围内,表明此爆破减震设计以及采取的减震技术措施满足设计和工程实际要求,为类似爆破施工控制技术提供了可以借鉴的依据。

  20. 兰新二线桥墩防风蚀措施及施工方法%Method and measure of wind-erosion prevention for bridge piers on Lanzhou-Xinjiang second railway

    Institute of Scientific and Technical Information of China (English)

    公彦良

    2016-01-01

    The second double-track rail line in Xinjiang of Lanzhou-Xinjiang railway crosses five strong wind areas. In order to solve the wind-erosion problem of bridge concrete piers,the measure of rigid-flexible combination of wind-erosion prevention was adopted by test. T he technology is a multistep process,using flexible polyester resin and steel wire webs to make a rigid-flexible composite on the surface of piers. It has high compressive and tensile strength,corrosion and erosion resistance,satisfactory anti-ultraviolet aging and durability,then contribute to wind-erosion prevention of bridge piers.%兰新铁路第二双线新疆段穿越新疆风力最强的五大风区,为了解决风蚀对兰新铁路桥墩混凝土结构的磨蚀问题,经过试验研究兰新铁路第二双线采取了刚柔结合的防风蚀措施。由柔性树脂胶加不锈钢丝网经过多道工序施工,在桥墩表面形成具有较高的压缩与拉伸强度、优良的耐风蚀和磨蚀性能、良好的耐紫外光老化性能及耐气候性的一种刚柔结合复合体,从而实现了桥墩抗风蚀的目标。

  1. Application of Stepped Enlarging Section Method in Railway Bridge Pier Reinforcement%阶梯式增大截面积法在铁路桥墩加固中的应用研究

    Institute of Scientific and Technical Information of China (English)

    路文尚

    2013-01-01

    The existing lines pier reinforcement usually increases piers lateral and longitudinal stiffness according to the enlarging section area method. The calculation and comparison results show that among the enlarging section area methods, the growth rate of foundation load of laddered enlarging section area method is the smallest, and the program is more economical, effective and operable. Through the field test of the Xianaohai Donggou Bridge in the Datong-Zhungeer railway and the practice of stepped enlarging section method, combined with the reinforcement design theory analysis and actual test results after reinforcement, it is concluded that the stepped enlarging section method is effective for lateral reinforcement of railway bridge piers, and it is easy to operate and worth learning and promotion.%  既有线桥墩加固通常通过增大截面积法,增加桥墩横向和纵向刚度。诸多增大截面方法中,通过计算对比,阶梯式增大截面积法基础负载提高率较小,方案较为经济、有效,可操作性强。通过大准线上的下脑亥东沟大桥的检测、阶梯式增大截面法加固的实践,结合加固设计理论分析和加固后实际测试结果,证明阶梯式增大截面法,对铁路桥梁横向振幅过大病害的加固效果较好,操作方便快捷,值得借鉴和推广。

  2. Application of the Turn-over Formwork in the Construction of the High Bridge Pier in Mountainous Region%浅谈翻板模在山区桥梁高墩施工中的应用

    Institute of Scientific and Technical Information of China (English)

    彭玉军

    2014-01-01

    四川雅砻江卡拉至杨房沟水电站交通专用公路洪水沟大桥桥墩施工时,利用2台10 t缆索吊吊运材料、设备,墩侧安装塔吊提升桥墩模板,缓冲溜管配合混凝土输送泵浇筑混凝土。安全、快速地完成了墩柱施工,保证工程质量,加快施工进度。该技术对其他类似工程具有借鉴作用。%In the construction of the pier of the accommodation road bridge for hydropower traffic (Hongshuigou Bridge) from Kala to Yangfanggou along Yalong River in Sichuan, two cable cranes with the lifting capacity of 10 tonnages were used to lift the materials and instruments while the pier formwork was lifted by the tower crane alongside and the concreting was done by the buffer chute and the concrete pump. The construction was completed fast and safely and will provide reference for other similar projects.

  3. Cause Analysis on Crack in Railway Bridge Pier Tray and Its Reinforcement Method%铁路桥梁桥墩托盘裂缝原因分析及加固方案

    Institute of Scientific and Technical Information of China (English)

    邵建国; 王起才

    2011-01-01

    文章基于宁夏灵武黄河特大桥桥墩托盘的裂缝调查情况,利用有限元模型从力学角度分析了托盘裂缝产生的原因,提出了预应力筋、碳纤维布、预应力筋+碳纤维布三种加固方案,并对比分析了各方案的加固效果。%Based on the crack investigation bridge pier tray of Ningxia Lingwu Huanghe Bridge,the article uses finite element model to analyze the formation of crack.It also proposes three reinforcement plan such as prestress reinforcing steel,carbon fiber sheet and steel + fiber sheet,and compares their performance.

  4. Cyclic Testing on Rectangular Hollow Bridge Piers Under Axial Load and Biaxial Bending%双向压弯状态下矩形空心桥墩循环试验

    Institute of Scientific and Technical Information of China (English)

    韩强; 杜修力; 赵彦; 王利辉

    2013-01-01

    To investigate the seismic performance of reinforced concrete (RC) rectangular hollow bridge piers, cyclic testing on five well-confined specimens was performed under constant axial load and biaxial bending. The test variables included axial load ratio, longitudinal reinforcement ratio and lateral reinforcement ratio. The results show that these specimens are flexural failure modes; biaxial force and displacement hysteretic loops show significant stiffness and strength degradation, pinching effect and coupling interaction of the structural seismic resistances in both directions; the ductility coefficient, varying from 3. 5 to 5. 7, and the equivalent viscous damping ratio, varying from 0. 19 to 0. 26, can meet the requirements of seismic design; RC rectangular hollow bridge piers with configurations of lateral reinforcement subject to bi-directional earthquake components have excellent earthquake resistance, and can substitute for current hollow RC rectangular section configurations described in the Chinese Guideline for Seismic Design of Highway Bridges (JTG/T B02-01-2008); and the length of the plastic hinge region is found to approach one sixth of the the hollow RC rectangular bridge pier height for all specimen piers, which is far less than the currently specified minimum value in Chinese Guideline, so the length of plastic hinge region is more concentrated for RC rectangular hollow bridge piers.%为了研究水平双向地震作用下矩形空心桥墩的抗震性能,对约束良好但轴压比和纵向、横向配筋率不同的5个钢筋混凝土(RC)矩形空心桥墩在轴力和双向弯曲作用下的性能进行了循环试验研究.结果表明:试件破坏形态为桥墩底部形成塑性铰的弯曲形破坏,桥墩双向力-位移滞回曲线显示了双向压弯状态下RC矩形空心桥墩刚度和强度退化、捏拢效应以及2个水平方向抗震性能的相互影响;试件桥墩的延性系数在3.5~5.7之间,等效粘滞阻尼系数在0

  5. 桥墩防撞导偏轮受撞后作用力及能量转换特性%Acting forces and energy transformation characteristics of anti-collision idler pulley for bridge pier under colliding

    Institute of Scientific and Technical Information of China (English)

    洪娟; 陈云鹤; 吴广怀

    2012-01-01

    为了避免船舶直接撞击运河桥墩,设计了—种适用于京杭运河航道的新型桥墩防撞导偏轮设施.依据船桥碰撞相关理论,通过不同船型与该新型防撞导偏轮设施碰撞过程的三维数值模拟,对船舶和防撞导偏轮设施碰撞后的作用力、能量转换及主要构件的碰撞损伤等特性进行了深入分析和评估.结果表明,该设施延长了撞击作用时同,可较好地保护碰撞船舶及桥墩,能够满足京杭运河桥墩防撞要求,并具有易更换、占地小和吸能效果明显的优点,适用于不同水深、流速、桥位的情况,可为内河桥墩防撞设计提供参考.%To avoid the loss from the direct collision between ships and bridge piers, a new anti-collision device of idler pulley was studied and designed to satisfy the characteristics such as the narrow channel of the Grand Canal. According to the relative ship-birdge collision theories, the acting forces, energy transformation characteristics and main components' collision damages during the colliding course between different types of ships and the new anti-collision device were analyzed and evaluated by 3D numerical simulation. The results indicate that the new device can prolong the collision acting time, protect both the ship and birdge pier and meet the anti-collision requirements for the bridge piers on the Grand Canal, which possesses the advantages such as easy replacing, little occupying area and obvious energy dissipating effect, and can be applied under different water depth, flow velocities and bridge positions. This new device can also provide a reference for the anti-collision design of canal bridges.

  6. The Reliability Analysis of Ship Collision with Thin-Walled High Bridge Pier Based on the Finite Element%基于概率有限元的船撞薄壁高桥墩可靠性分析

    Institute of Scientific and Technical Information of China (English)

    包龙生; 李亮; 于玲; 石玉洪; 张肇红

    2011-01-01

    目的 对大跨径连续刚构桥薄壁高墩施工期间船撞荷载作用下进行可靠性计算及敏感性分析,得到薄壁高墩在船撞荷载下的可靠概率.方法 采用ANSYS有限元软件提供的APDL语言与求解可靠度的Monte-Carlo法相结合,通过对随机输入变量的抽样,对船舶撞击薄壁高墩进行可靠性计算,并对设计参数进行敏感性分析.结果 在置信度为95%时,薄壁高墩在船撞荷载作用下的可靠性为100%;船撞荷载的变异性对最大应力的相关系数最大为0.2916.结论 利用Monte-Carlo法中的拉丁超立方抽样方法计算桥梁的可靠度能够真实反映出桥梁的可靠性,该方法具有较高的效率和使用价值.%This paper aims at analyzing the reliability and sensitivity of ship collision with thin-walled high pier during the span continuous rigid frame bridge construction. And the structural failure caused by the potential risk can be calculated. Combined the APDL language in the finite element software ANSYS with Montecarlo method about reliability solution, the reliability of ship against thin-walled high pier was calculated and the parameters' sensitivity was analyzed through the sampling of random input variables. In the confidence level of 95% ,the reliability of the thin-walled high pier with ship collision loads is 100%. And the variation of ship collision loads on the correlation coefficient of maximum stress is 0.2916, which is the biggest. The reliability of the bridge calculated by Latin hypercube sampling method of Montecarlo method can reflect reliability of the bridge truly. The method has high efficiency and value.

  7. V形墩连续刚构桥静动力行为及地震响应分析%Analysis of Static and Dynamic Behaviors of Continuous Rigid Frame Bridge with V-Shaped Piers and Seismic Response

    Institute of Scientific and Technical Information of China (English)

    程炜钢; 徐伟; 冯东明

    2012-01-01

    Based on a 3-D FEM simulation model of Xinyanggang continuous rigid frame bridge with V-shaped piers, a space finite element model is established by using Midas/civil 2010, a structure analysis software, to simulate and study the whole construction process of the bridge. In addition, the internal force, stress and deformation of the main bridge under unfavorable load combination at different construction and running stages are calculated; a dynamic analysis is then carried out. Also, the stress and the seismic response of this bridge under E1 earthquake action are analyzed by adopting response spectrum method and dynamic time-history analysis method, respectively. The calculation results indicate that the stress of the main bridge in the course of construction and running is reasonable, which satisfies the standard requirements; the displacement response of the main bridge in an earthquake is not strong; vertical seismic force produces enormous impacts on the axial force of the V-shaped piers and the internal force of the middle main span. The results of the calculation can provide reference for antiseismic designs.%以新洋港V墩连续刚构桥为工程背景,采用结构分析软件Midas/civil2010建立空间有限元模型,进行施工全过程仿真分析,计算主桥各个施工阶段和运营阶段不利荷载组合下的内力、应力和变形情况;同时,进行动力特性分析,并分别用反应谱法和一致时程激励法计算主桥在El地震作用下的内力和位移响应.计算表明,施工及运营阶段主桥受力合理,满足规范要求;地震作用下的位移响应较小,考虑竖向地震作用对V墩轴力和主跨跨中内力影响较大,计算结果可为抗震设计提供依据.

  8. 嘉绍大桥主墩双壁钢围堰施工技术%Construction Techniques of Double-Wall Steel Cofferdams for Main Piers of Jiashao Bridge

    Institute of Scientific and Technical Information of China (English)

    宋华清; 唐衡; 林道锦

    2012-01-01

    The main shipping channel bridge of the Jiashao Bridge is a steel box girder cable-stayed bridge with six pylons and four cable planes and the six pile caps of the main piers of the bridge were constructed by the double-wall steel cofferdams. The maximum diameter of the cofferdams is 43. 65 m, the spacing distance between the inner and outer walls of a cofferdam is 1. 5 m, the height of the cofferdam is 26 m and additionally a cofferdam was also provided with eight groups of the combined guiding and positioning devices (guiding piles-sliding steel brackets) arranged in a center-tocenter symmetric way. All cofferdams were manufactured piece by piece in the workshop and at a pier site, the assembling platform for the cofferdam was set up in between the steel casings and platform piles and the cofferdam was well assembled in one time by the gantry carne, using the pier site assembling construction technology. The cofferdam was then lowered down by the sinking system synchronously controlled by computer and was sunk down in place by the aid of the unbalanced ballast and the "inverse pan" dredging. Practice proves that the six cofferdams for the main piers of the bridge have been finally smoothly sunk down in place. The plan deviations of the cofferdams are 50~90 mm and the perpendicularity is less than 1/400, which all satis.fy the relevant requirements in the codes.%嘉绍大桥主航道桥为六塔四索面钢箱梁斜拉桥,6个主墩承台均采用双壁钢围堰方案施工.钢围堰最大直径43.65m,内、外壁间距1.5m,高26 m,以中心对称的方式布设8组组合导向定位装置(导向桩+滑动钢牛腿).钢围堰在加工场内分片制作,在钢护筒与平台桩间搭设拼装平台,采用原位拼装工艺,利用龙门吊一次组拼成型;采用计算机同步控制下沉系统下放,辅以不均衡配载和“倒锅底形”吸泥工艺下沉到位.实践证明,该桥6个主墩钢围堰均顺利下沉到位,平面偏位50~90 mm

  9. Application of viscous dampers to seismic response control of a high-pier continuous bridge%粘滞阻尼器在高墩连续梁桥抗震设计中的应用

    Institute of Scientific and Technical Information of China (English)

    刘朝福; 杨起; 保石才

    2011-01-01

    以大理州鸡足山旅游公路宝丰寺大桥为工程背景,基于桥梁地震动方程建立了空间非线性有限元模型,研究粘滞阻尼器参数及其设置位置对山区高墩连续梁桥减震效果的影响,并同其他减震措施进行了比较,以分析进行高墩连续梁桥减震设计的合理方法.计算结果表明,粘滞阻尼器在高墩连续梁桥的抗震设计中具有优越的性能,对结构的位移控制以及内力的耗散作用非常明显,而铅芯橡胶支座由于附加刚度的影响造成边矮墩内力过于集中,在减震性能上不及粘滞阻尼器;粘滞阻尼器的安装位置对结构减震性能具有较大的影响,设计时须充分考虑,以确保结构的减震性能和工程的经济性.%By taking the Baofengsi Bridge on the tourist road of Jizu Mountain in Dali Autonomous Prefecture as the research object, a spatial nonlinear finite element model was established based on the seismic dynamic equation of bridge. The proposed model was used to analyze the effects of the parameters and locations of viscous dampers on the seismic response of the high-pier continuous bridge in mountainous area, then the results were compared with other measures of mitigating seismic response in order to explore the most effective means for getting seismic response control of the high-pier continuous bridge. The results indicate that the viscous damper has superior performance on mitigating the seismic response of the high-pier continuous bridge, particularly on the displacement control of the structure and the dissipation of inner force. The seismic response control of lead rubber bearing is not as good as that of viscous damper, because the force of low piers is too centralized by its added stiffness. In order to ensure the seismic response control of the structure and the economy of project, the designers must take the location of the viscous damper into account because it has a major impact on the mitigation of the

  10. 高墩大跨连续刚构桥的稳定性分析%Analysis of Stability of Long-span Continuous Rigid Frame Bridge with High Pier

    Institute of Scientific and Technical Information of China (English)

    王菲; 田山坡; 禚一

    2012-01-01

    Research purposes: The highway in western China or the remote region needs to cross over rivers and valleys and passes the regions with complex terrains due to the limitation of topographical condition . For this reason, the long -span continuous rigid frame bridge with high pier becomes more and more and the height of the bridge increases from several decameters to hundreds of meters. With increases of the pier height and the span length, the research on the stability of such kind of bridge is becoming more and more important. Research conclusions:Taking the long - span continuous rigid frame bridge with(90 + 168+90) m high pier in Shanxi province as the engineering background, the basic principle related to the structure stability is discussed and the stability of the high pier, the stability of the longest cantilever during construction and the stability in complete stage of the bridge are analyzed. From the calculation results it can be seen that for the bridge presented in this paper, the temperature effect has a little influence on the high pier stability, the wind load along the bridge axial direction has the most negative impact on the structure stability in the construction stage of the longest cantilever, and during the complete stage of the bridge, the lane load and the load of the crowded people set on the middle span has the most negative impact on the bridge stability. Furthermore, wind has a little influence and the influence of the temperature effect can be ignored in this stage. The calculation results also show this bridge has a good stability during its construction process and in the complete stage of bridge. The calculation and analysis processes presented in this paper can provide the reference to the similar works.%研究目的:西部地区及偏远地区受地形条件的限制,修建公路时常需要跨越河流、沟谷等复杂地形,因此高墩大跨连续刚沟桥的修建日益增多,其墩高也由原来的几十米提

  11. Analysis of P-△ effect of railway bridge with high-rise piers under action of vertical earthquake%竖向地震动作用下的高墩桥梁P-△效应分析

    Institute of Scientific and Technical Information of China (English)

    杨涛

    2012-01-01

    以在建的西平线上某高墩铁路桥为工程背景,建立相应的动力模型,重点分析竖向地震动作用时P-△效应对高墩铁路桥梁的影响。结果表明,在同时考虑到竖向地震作用和P-△效应之后,由于非线性的影响,竖向作用加强了水平地震动的影响,从而加大了桥梁的水平反应。%This article takes the railway bridge as an engineering background, using finite element software to establish dynamic model. Analysis of P -△ effect of railway bridge with high-rise piers under the action of vertical earthquake. The results of the study show that due to the influence of nonlinear, the action of vertical earthquake strengthened the influence of horizontal earthquake reaction considering the action of vertical earth- quake and effect of P -△effect. Provide a reference for Aseismic optimum design of this bridge.

  12. 浅埋式桩基础钢筋混凝土拱桥桥墩防撞安全性评价与加固技术研究%Pier anti-collision safety evaluation of reinforced concrete arch bridge with shallow-buried piles and its strengthening technology research

    Institute of Scientific and Technical Information of China (English)

    吴超; 李德建; 宁夏元; 胡先春

    2013-01-01

    On the background of Yuan River bridge in Wuqiangxi,a method of pier anti-cillision safety evaluation,based on "Highway Bridge Code for Design",was put forward for reinforced concrete arch bridge with shallao-buried piles.On the basis of safety evaluation of Yuan River Bridge pier,a pier strengthening project of Yuan River Bridge in Wuqiangxi was proposed.In order to simulate the interaction of new and old concrete after strengthening of foundation,three-dimensional solid elements were adopted,where two situations of the interface between new and old concrete,i.e.,fully bonded or sliding were taken into account.The feasibility of this pier reinforcement project was studied,which can also provide reference for the similar bridge strengthening engineering.%以五强溪沅水大桥为工程背景,针对浅埋式桩基础钢筋混凝土拱桥,提出基于我国公路桥涵设计规范桥墩防撞安全性评价方法.通过对该桥的桥墩防撞安全性评价提出了相应的桥墩加固方案.采用三维实体单元来模拟基础加固后新老混凝土的共同作用,同时考虑新老混凝土接触面按完全粘结与滑动2种情况建立计算模型,对桥墩防撞加固方案的可行性进行了研究,亦可供同类桥梁加固参考.

  13. 地震作用下超高墩刚构桥倒塌易损性分析%Seismic Collapse Fragility Analysis of Rigid Frame Bridge with Super High Piers

    Institute of Scientific and Technical Information of China (English)

    范振华; 张谢东; 张行

    2013-01-01

    防止地震作用下结构倒塌是基于性能的地震工程的核心目标,目前基于弹塑性时程分析的倒塌易损性分析是结构抗倒塌能力评价最合理的方法.倒塌易损性分析的关键之一是建立合理的倒塌判别准则,文中提出了超高墩刚构桥地震倒塌破坏的判别准则.结合某工程实例,基于OpenSees建立了结构的非线性分析模型,对其进行了非线性地震时程分析,在此基础上建立了结构的易损性曲线,并讨论了混凝土保护层剥落和钢筋锈蚀等结构劣化对倒塌易损性的影响.%An important goal of performance-based seismic design is to prevent collapse of bridges.At present collapse fragility analysis based on the elasto-plastic time-history calculation is the most reasonable method to evaluate the collapse ability.The collapse criterion is the most important problem to be resolved.In this paper,a criterion of collapse for rigid frame bridge with high piers is proposed.An engineering example is demonstrated to study the collapse fragility of a rigid frame bridge with super high piers.The structure model is establish by OpenSees and the nonlinear time-history calculation is carried out to obtain the collapse fragility.Also the effect of deterioration,such as concrete spalling,the decreasing of strength and area of reinforcement,on the collapse fragility is discussed in detail.

  14. 船桥碰撞过程中桥墩塑性防撞装置性能研究%Study on performance of plastic anti-collision device of pier suited to collision of boat against bridge pier

    Institute of Scientific and Technical Information of China (English)

    韩东; 钟铁毅; 信坤; 贾鹏

    2014-01-01

    随着交通运输的发展,船桥碰撞事件时有发生。现有规范中撞击力计算公式通常只考虑船舶质量和速度,对刚度考虑不足。本文利用有限元软件ANSYS LS-DYNA进行仿真模拟,以不同的钢板厚度反映刚度变化,分析船舶结构和防撞装置刚度变化对撞击力以及碰撞过程的影响。研究结果表明:碰撞过程中船舶的动能主要被防撞装置和船舶结构通过塑性变形吸收,防撞装置相对刚度越小,其吸收的碰撞能越大;最大撞击力主要受船舶结构和防撞装置二者刚度较小者的影响,船舶结构刚度相对较小时,最大撞击力随船舶结构刚度的增加而增加;防撞装置的刚度较小时,最大撞击力随着防撞装置刚度的增加而增加;在进行桥梁防撞设计和验算时,除要考虑船舶刚度的影响外,还应根据通航水域的实际情况,确定防撞装置钢板厚度的合理范围。%With the development of transportation ,ship-bridge collision incidents have always occurred . The calculation formula of the collision force in the existing standard only cares about the quality and the speed of the ship and the stiffness factor is not under consideration .This paper analyzed the impact of stiffness of ship structures and anti-collision devices on the collision force and the collision process by using finite element software ANSYS LS-DYNA, which simulates the stiffness variation reflected by different steel plate thickness .The results showed that kinetic energy in the ship-bridge collision process is mainly absorbed by the plastic deformation of the anti-collision device and the ship structure , the smaller the relative stiffness of anti-collision devices is,the more will the collision energy be absorbed , the maximum collision force is mainly affected by the smaller one between ship structures stiffness and anti-collision devices stiffness, the maximum collision force will increase with the

  15. 大差异墩高桥梁隔震性能对比分析研究%Seismic Isolation Analysis Study on Big Different Pier Height Bridge With Plate and Lead Rubber Bearing

    Institute of Scientific and Technical Information of China (English)

    伍波

    2015-01-01

    For the comparation of plate bearing and lead rubber bearing under severe earthquake, the seimic analysis subject of setting plate bearing and lead rubber bearing in the bridge were studied on the basis of SaMiKa bridge. Two bridge models with ordinary plate bearing and lead rubber bearing were calculated separately, and the dynamic characteristics of the bridge, the changes of moment, shear force and displacement of the bridge columns were compared under the design basis earthquake and maximum considered earthquake. The calculated results show that, the thickness and anti-slide stability of the ordinary plate bearing do not meet the requirements of specification when it subject to the maximum considered earthquake in the dynamic analysis of the bridge. While using lead rubber bearing, the internal force performance was improved greatly, pier column anti-shear strength all met the requirements, the bending resistance ability was also improved.%本文以撒米卡大桥为例,对桥梁设置普通板式支座和铅芯隔震橡胶支座这两种工况下该桥梁的隔震性能进行了对比分析研究。分别计算了设置普通板式支座和铅芯隔震橡胶支座的两种桥式,比较了在设防地震和大震作用下,两种桥式结构的动力特性及桥墩墩柱的弯矩、剪力、位移变化的情况。计算结果显示,对于动力特性,采用铅芯橡胶隔震支座的结构自振周期明显小于普通板式支座;对于结构内力,在大地震作用下,普通板式支座的厚度及抗滑稳定性均不满足规范要求;墩的内力还是远远超过塑性极限,不满足理论要求。而采用铅芯隔震橡胶支座,墩的内力得到大大改善,隔震计算后墩柱抗剪均满足要求,抗弯能力也得到一定的改善。

  16. Seismic Damage Analysis of Reinforced Concrete Bridge Piers Based on Beam-Column Elements%基于梁柱单元的钢筋混凝土桥墩地震损伤分析

    Institute of Scientific and Technical Information of China (English)

    李正; 李忠献

    2011-01-01

    Faria-Oliver model is a simple and effective damage model for concrete.The uniaxial version of the FariaOliver damage model was proposed in the present paper.Meanwhile, the modification of Faria-Oliver model was introduced to describe the unilateral effect of concrete more properly.In addition, the material subroutines i.e.the modified Menegotto-Pinto model for reinforcing steel and the uniaxial modified Faria-Oliver model for concrete were implemented into VUMAT and the equivalent modeling strategy of fiber model was established within the FEA software ABAQUS.Furthermore, the numerical simulations of a cyclic loading test and a shaking table test of the reinforced concrete (RC) bridge piers were conducted.The results of the numerical simulations agreed well with the experimental ones.The present study indicates that the aforementioned uniaxial constitutive models and the equivalent modeling strategy of fiber model are effective and the seismic analysis of RC bridge piers using beam-column elements not only has a high computational efficiency but also provides information about seismic damage evolution.%Faria-Oliver模型是一个简单而有效的混凝土损伤模型.基于Faria-Oliver模型提出了混凝土单轴损伤模型,且加以修正以更好地模拟混凝土单边效应;在ABAQUS软件平台上,编制了含有钢筋修正Menegotto-Pinto模型和混凝土单轴修正Faria-Oliver损伤模型的用户材料子程序VUMAT,建立了纤维模型等效模拟方法;分别模拟了一钢筋混凝土桥墩试件的循环加载试验和一钢筋混凝土桥墩试件的振动台试验,模拟结果与试验结果基本吻合.研究表明:本文所给出的单轴本构模型及纤维模型等效模拟方法有效、适用;基于梁柱单元的钢筋混凝土桥墩地震损伤分析不仅计算效率高而且提供了地震损伤演化过程信息,具有较强的工程实用性.

  17. USE OF SURFACE GUIDE PANELS AS PIER SCOUR COUNTERMEASURES

    Institute of Scientific and Technical Information of China (English)

    Chin-Kun HUANG; Chii-Jau TANG; Ting-Yuan KUO

    2005-01-01

    This paper presents a laboratory study on bridge pier protection with surface guide panels (SGP) in clear-water experiments. The SGP is installed by piercing a set of two vertical panels partially into the water, with some interior angle and leading opening, setting at a distance ahead of the protected pier. The suitable installation of the SGP can effectively adjust the flow pattern to reduce the downflow motion and the horseshoe vortex ahead of the pier. We consider some dominant factors to set up SGP for pier protection, including the interior angle θ, leading opening Ow, distance between panel and pier L, submerged depth of panel Pd, pier diameter D and water depth H. After evaluation of these parameters through laboratory tests, the optimal setup conditions of θ=60o, Ow/D=0.1~0.2, L/D=2~2.5 and Pd/H=0.7 are determined. Under these conditions, the usage of SGP leads to a best performance on decrement of the maximum scour depth at pier up to 90% with ignorable side effects on the SGP scour.

  18. Segmental joint behavior analysis of a high performance multifunctional permanent form work of a bridge pier%高性能多功能桥墩永久模板节段节点性能分析

    Institute of Scientific and Technical Information of China (English)

    吴香国; 陈思远; 赵新宇

    2012-01-01

    为了给高性能多功能桥墩永久模板节段节点设计提供科学依据,根据超高性能水泥基复合材料( UHPCC)纵向节段间的节点联接构造,分析了界面应力,建立了切向应力和法向应力分量的表达,提出了界面联接率的设计参量,并给出了焊缝节点应力极限状态方程.基于荷载规范,给出了永久模板的施工荷载计算参量表达.简要介绍了UHPCC的基本性能、计算模型,提出了将UHPCC应用于桥墩用多功能永久模板的设计概念,并结合典型墩柱结构进行了UHPCC管界面节点性能的计算,分析了壁厚、焊缝有效厚度等设计参量对节点性能的影响规律,分析了界面联接参量对焊缝应力的影响规律,提出了UHPCC管连接节点的设计方案.该研究为UHPCC永久模板管结构节段节点强度设计奠定了基础.%In order to propose trre scientific basis for the segmental joint design of the high performance and multifunctional permanent form work of a pier, the interfacial stress was analyzed according to the segmental joint structure of longitudinal sections of ultra high performance cementitious composites (UHPCC), and the expressions of tangential stress and normal stress were given, the design parameters of interface connection rate was proposed, and the ultimate state equation of the weld joint stress was given. Based on the construction load code, the calculating parameter expressions of construction loads for the UHPCC thin circular tube were presented. The basic properties and calculating constitutive model of UHPCC were introduced. The design concept of applying UHPCC into multifunctional permanent form work for bridge piers was presented in this paper. With geometrical dimensions of a typical pier, the interfacial joint performance parameters of a UHPCC tube under typical construction loads were calculated. The effect of the geometrical parameters such as wall thickness and effective thickness of a weld joint on the

  19. RISK LEVEL ANALYSIS ON THE PREVENTIVE EROSION CAPACITY OF BRIDGES

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Deficiency of the Preventive Erosion Capacity (PEC) of a bridge pier is the main factor leading to bridge failures. In this paper, the PEC of bridge piers was analyzed using the stochastic analysis method. The definitions of the reliability and risk level of a bridge pier subjected to water erosion were proposed and a computational model for erosion depth and risk level in was suggested.

  20. Stress Analysis of Pier-tower-girder Fixed Region of Cable-stayed Bridge with Trough Girder%槽型断面梁斜拉桥塔梁墩固结区受力特性研究

    Institute of Scientific and Technical Information of China (English)

    戴公连; 粟淼; 刘文硕; 闫斌

    2014-01-01

    In order to increase the structural longitudinal stiffness and facilitate the swing method,the side girders of trough section of the cable-stayed bridge on the Kunming-Shanghai passenger line were in-serted into the pylon so as to form the pier-tower-girder fixed region.For the (32+80+112)m single tower cable-stayed bridge,the structure and force of the fixed region are very complicated.The large gen-eral-purpose finite element software ANSYS was used to establish the pier-tower-girder fixed region model to study the stress distribution of the fixed region.The correctness of this model was verified.Based on this region model,the force transmission and stress distribution of the fixed region were investigated,and the effect of the local structural details on the fixed region stress was studied.The analysis results show that the global stress level of the fixed region is lower than the girder and tower,but there are stress con-centration phenomena in the fixed region,such as the intersection point between the floor of the trough girder and upper tower,and the corner of the human tunnel in the fixed region.The degree of the stress concentration was relieved significantly by improving the structural details.%为增大桥梁纵向刚度、便于转体施工,沪昆客运专线上某(32+80+112)m 槽型截面独塔斜拉桥将槽型梁两边箱插入塔柱中形成塔梁墩固结体系,其构造和受力情况极为复杂。为研究该桥塔梁墩固结区域的应力分布情况,采用大型通用有限元软件 ANSYS建立塔梁墩固结区局部模型并验证模型正确性。在此基础上,分析固结区域结构传力路径和应力分布规律,探讨局部设计细节对固结区应力的影响。研究表明:塔梁墩固结区内整体应力水平低于固结区范围以外截面,但在槽型梁过渡至固结区内部的交接角以及固结区内部过人洞折角等处存在应力集中现象。通过改进结构设计细节可有效缓解各处的应力集中现象。

  1. 襄樊汉江三桥主墩承台大体积混凝土施工技术%Large Volume Concrete Construction Technology of Hanjiang the Third Bridge Main Pier Pile Cap in Xiangfan

    Institute of Scientific and Technical Information of China (English)

    吴刚; 蒲赞全; 钟启凯; 刘开扬

    2011-01-01

    Based on the large volume pile cap construction of Hanjiang the Third Bridge main pier in Xiangfan,the construction technology of the large volume pile cap is analyzed. , including cofferdam construction of steel sheet pile, bottom sealing of underwater concrete. A series of measures from concrete raw material to concrete pouring are taked to prevent exorbitant hydration temperature in mass concrete causing concrete crack, including mix design of low hydration heat concrete, temperature control calculation of concrete, field temperature control measures of mass concrete, temperature monitoring during construction. Thus,pile cap construction is completed successfully.%结合襄樊汉江三桥主墩大体积承台施工,分析了大体积承台施工技术,包括:钢板桩围堰施工,水下混凝土封底.为防止大体积混凝土在水化过程中结构内部产生过高的水化热温度,致使结构产生有害裂缝,从混凝土原材料到混凝土浇筑施工采取了一系列有效的技术控制措施,包括低水化热混凝土配合比设计、混凝土温控计算、大体积混凝土温度现场控制措施,以及施工过程中的温度监测,从而使得承台施工得以顺利完成.

  2. 大跨高墩小半径刚构—连续组合梁桥地震响应分析%Analysis of Seismic Response of Long Span, High-Rise Pier and Short Radius Curved Hybrid Bridge of Rigid Frame and Continuous Girder

    Institute of Scientific and Technical Information of China (English)

    揭志羽; 卫星; 李亚东; 顾颖

    2013-01-01

    To study the seismic response of the long span, high-rise pier and short radius curved hybrid bridge of rigid frame and continuous girder, a railway bridge of the same structural type with span arrangement (40 + 6×80 + 40) m was cited as an example and analyzed. The AN-SYS was used to set up the finite element model for the whole bridge of the bridge, the dynamic properties of the bridge were calculated and the internal forces and displacement under the seismic action were analyzed, using the response spectrum method and the time-history analysis method. The results of the analysis reveal that the increase of rigidity of the bridge piers and the application of rigid fixity of the piers and girder can improve the integrality of the curved hybrid bridge of rigid frame and continuous girder and are advantageous to the seismic resistance. In comprehensive consideration of the seismic response (e. g. displacement and moment) , the worst seismic wave excitation angles of the bridge of such type are 0°and 90° (respectively corresponding to the longitudinal and transverse directions of the bridge). The increase of the transverse rigidity can decrease the displacement of the bridge in the transverse direction and the increase of the sectional areas of footings of the piers can reduce the seismic response of the bridge under the horizontal seismic action. In general, the transverse displacement and out-of-plane moment of the bridge under the seismic wave excitation in the transverse direction are the maximum while the longitudinal displacement and in-plane moment of the bridge under the excitation in the longitudinal direction are also the maximum.%为研究大跨高墩小半径刚构-连续组合曲线梁桥的地震响应,以某(40+6×80+40)m的刚构-连续组合梁铁路特大桥为背景进行分析.采用ANSYS建立全桥有限元模型,计算桥梁动力特性,并采用反应谱法和时程分析法对桥梁在地震作用下的内力和位移进行分析.分析

  3. Application of ANSYS in Analysis for Stress Stability of Bridge Piers under Effect of Impact (Collision) Load%ANSYS在冲击(撞击)荷载作用下桥墩应力可靠度分析中的应用

    Institute of Scientific and Technical Information of China (English)

    詹万成; 吴云果; 吴士金

    2013-01-01

    On the basis of large universal finite element software-ANSYS probability design system,this paper proposes the methods of analysis for reliability of bridge piers at the maximum stress under the effect of impact load by means of the ANSYS probability analysis function.This paper calculates structural reliability of bridge piers under the effect of random variables including impact load,load position,elastic modulus and density,etc.by means of the central composite design of ANSYS to obtain series conclusions of important values such as reliability index of response to stress and failure probability of bridge piers as well as relative sensitivity of the max.stress to various random variables.%基于大型通用有限元软件ANSYS概率设计系统,提出利用ANSYS概率分析功能对桥墩在冲击荷载作用下最大应力进行可靠性分析的方法.采用ANSYS的中心复合设计法,对桥墩在冲击荷载、荷载位置、弹性模量以及密度等随机变量作用下的结构可靠度进行计算,获得桥墩应力响应的可靠度指标和桥墩的失效概率,以及最大应力与各个随机变量的相关灵敏度等一系列具有重要价值的结论.

  4. 辅助墩对混合梁斜拉桥非线性静动力特性的影响%Impacts of auxiliary pier upon non-linear static and dynamic characteristics of single staved-cable bridge with composite beam

    Institute of Scientific and Technical Information of China (English)

    钟加峰

    2012-01-01

    利用有限元分析软件建立了混合梁独塔斜拉桥的空间模型,分析了混合梁独塔斜拉桥在有、无辅助墩情况下的非线性静动力特性的异同,讨论了在有、无辅助墩情况下对混合梁独塔斜拉桥非线性静动力特性的影响,得出了有指导意义的结论。%The paper establishes spatial model of single stayed-cable bridge with composite beam by using finite element analysis software, ana- lyzes similarities and differences of non-linear static and dynamic characteristics of single stayed-cable bridge with composite beam under the con- dition of with and without auxiliary pier, and discusses the impacts of within and without auxiliary pier upon non-linear dynamic and static char- acteristics of single stayed-cable bridge with composite beam, and finally draws some guiding conclusions.

  5. 自重作用下高墩大跨曲线连续刚构桥空间受力分析%Space Structural Analysis of Curved Continuous Rigid-frame Bridge with High Piers and Long Spans under the Gravity Action

    Institute of Scientific and Technical Information of China (English)

    张坚; 吕昌武

    2013-01-01

      以一座典型的连续刚构桥为背景,考虑悬臂施工阶段结构自重与悬浇预应力的影响,通过选取不同的曲率半径及墩高,利用有限元程序对最大悬臂状态施工阶段的曲线连续刚构桥应力和变形进行了分析,重点研究了曲率及墩高的影响。通过分析,为曲线刚构桥提供了相应的设计建议和施工控制思路。%Take a typical continuous rigid-frame bridge as the background, and through the selection of curvature radius and pier height, this paper takes the influences of stage structure self-gravity of cantilever construction and suspended casting prestress into consideration, and analyses the stress and deformation of curved continuous rigid-frame bridge in the biggest cantilever construction stage with finite element program, pays much attention to the research of the influences of curvature and pier high. Through the analysis, the author provides the corresponding design suggestions and construction control ideas for the curved rigid-frame bridge.

  6. 粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅱ:动力响应数值分析%Anti-seismic properties of damaged concrete bridge piers with hollow cross-section strengthened with adhering steel platesⅡ:numerical analysis on seismic dynamic responses

    Institute of Scientific and Technical Information of China (English)

    邓江东; 宗周红; 黎雅乐; 刘爱荣

    2013-01-01

    The flexibility method and the fiber model were used to numerically simulate the earth-quake dynamic response of the damaged concrete bridge piers with hollow cross-section strengthened with adhering steel plates.The performance index,such as the seismic forces at the piers bottom, pier top displacement and residual stiffness,were analyzed,and on the basis of model tests the seis-mic mechanics behaviors of the strengthened piers were comprehensively studied.The analysis re-sults show that the failure modes of the strengthened bridge piers under the earthquake actions are al-so displayed as the occurrences of plastic hinge in the superior margin of the steel plates,which coin-cides with the pier model testing results.The comparison of the seismic performances before and af-ter strengthening validates the effectiveness of the strengthening method with steel plates of making new plastic hinge.The effects of the initial damage degree,steel plate thickness and slenderness rati-os on the seismic safety degrees of the bridge piers are small.However,when the axial compression ratio is large,the seismic safety degrees decrease quickly.%针对具有初始弯曲损伤的粘钢加固混凝土箱型桥墩,采用柔度法和纤维模型,进行了系统的地震动力响应数值模拟计算,分析了地震作用下加固桥墩的地震剪力、墩顶位移、剩余刚度等性能指标,并在拟静力试验的基础上综合研究其抗震加固力学行为。分析结果表明,地震荷载作用下地震中桥墩仍然发生加固钢板上缘产生塑性铰的破坏模式,与拟静力试验结果一致。加固前后桥墩抗震性能的对比结果表明,经粘钢加固形成新塑性铰的加固方式可有效增强桥墩的抗震能力。初始损伤程度、加固钢板厚度和长细比等对加固桥墩抗震安全度的影响较小。大轴压情况下,安全度快速降低。

  7. 差动和波浪力激励下海床-桩-墩-桥的地震弹塑性:原理、方法、程序与智能建模%ELASTO-PLASTICITY ANALYSIS OF BRIDGE ACCOUNTING FOR SPATIAL VARIABILITY OF EARTHQUAKE MOTIONS AND BRIDGE PILE-PIERS-SOIL INTERACTION: THEORY, METHOD, PROGRAM AND INTELLIGENT MODELLING

    Institute of Scientific and Technical Information of China (English)

    柳国环; 练继建; 燕翔

    2015-01-01

    Numerical studies on seismic responses of a long-span bridge pier-pile-soil system relate with the following several aspects:the reasonability and convenience of the finite element model for a long-span bridge pier-pile-soil system,the validity of approach for multi-point earthquake motions at underground locations,the wave force and effect of hydrodynamic pressures-induced added mass;and multi-source visco-elastic artificial boundary conditions.Firstly,the essential difference between the long-span bridge pier-pile-soil system with and without artificial boundary conditions is expounded and pointed out.Then,a feasible and effect path for the inversion of earthquake motions is given and proposed,accounting for spatial variability,at under-ground location from ground surface,and the corresponding visible program called MEMS_c (Multiple Earthquake Motions Simulation_c) is further developed successfully.Further,a visual program named WFS (Wave Force Simulation) is developed and illustrated based on the wave force and its spectral characteristics for small-scale structures.At last,in order to improve the efficiency and flexibility of preprocessor,a quick workflow for establishing numerical modeling is presented and the visual modeling tool Foundation 2013.6 is developed.The content involves theory and practicability.It can be directly applied to the follow-up engineering.%跨海大跨桥梁体系在地震作用下的弹塑性数值模拟涉及四个问题:1)海床(地基)-桩-墩-桥建立整体模型的合理性便捷性;2)地下地基位置多点地震动反演途径的有效性;3)波浪力和水动附加质量;4)无限域地基被有限域地基代替后,粘弹性人工透射边界及其多源性.首先,阐述并指出了有无粘弹性人工透射边界下,土-结构体系地震差动输入模型的激励输入模式的本质区别;然后,提出了一种有效的地基位置具有空间变异性的地震差动反演途径,并据此成功开

  8. 安庆长江铁路大桥主墩大型深水基础施工方案与关键技术%Construction Scheme and Key Construction Techniques for Large Deepwater Foundations of Main Piers of Anqing Changjiang River Railway Bridge

    Institute of Scientific and Technical Information of China (English)

    农代培; 季跃华; 徐炳法

    2012-01-01

    宁安铁路安庆长江铁路大桥主桥为双塔多跨连续钢桁梁斜拉桥,该桥3号、4号墩均采用高桩承台基础.为解决桩基汛期施工风险大和3号墩深水无覆盖层斜岩面环境下桩基施工平台搭建难题,经方案比选,3号、4号墩基础采用先围堰(直径56 m)后平台的双壁钢围堰施工方案.施工中采取了以下关键技术:3号墩围堰采用气囊法下河,4号墩围堰采用整体起吊下河;围堰采用无导向船重锚锚碇系统定位;采用活动插板法快速完成了斜岩面围堰底缺口封堵;围堰采取了分区封底施工.%The main bridge of Anqing Changjiang River Railway Bridge on Nanjing-Anqing Railway is a double-pylon and multi-span continuous steel truss girder cable-stayed bridge and the main piers No. 3 and No. 4 of the bridge are supported on the elevated pile cap foundations. To cope with the problems that the construction risk of the pile foundations would be high in the flood period and the setting-up of the working platform would be difficult for the foundation of the Pier No. 3 on the inclined rock surface in deepwater and without overburden, it was determined through comparison that the construction scheme of building the circular double-wall steel boxed cofferdams (each being 56 m in diameter) for the Piers No. 3 and No. 4 first and setting up the platforms late would be adopted. In the process of the construction, the following key techniques were applied, I. E. The cofferdam for the Pier No. 3 was launched to the river by the air bag method and the cofferdam for the Pier No. 4 was integrally lifted down to the river. Both the cofferdams were positioned at the pier sites by the heavy anchor anchorage systems without utilizing the guiding barges. The opening at the bottom of the cofferdam on the inclined rock surface was fast blockaded by the movable inserted steel plate method and the bases of the two cofferdams were sealed by tremie concrete in areas.

  9. 76 FR 66274 - Small Takes of Marine Mammals Incidental to Specified Activities; Pier 36/Brannan Street Wharf...

    Science.gov (United States)

    2011-10-26

    ... similar to an APE 150, which produces up to 1,800 vibrations per minute. All impact pile driving would use... Bay Bridge. More specifically, this area is located between Pier 30-32 and Pier 38, directly adjacent... background, sound is a mechanical disturbance consisting of minute vibrations that travel through a...

  10. Design of Main Pier Foundations for Guyumen Channel Bridge of Pingtan Strait Rail-cum-Road Bridge%平潭海峡公铁两用大桥鼓屿门航道桥主墩基础设计

    Institute of Scientific and Technical Information of China (English)

    孙英杰; 梅新咏

    2016-01-01

    平潭海峡公铁两用大桥鼓屿门航道桥采用主跨364 m的钢桁混合梁斜拉桥方案,桥址区水深流急、风大涌险、潮大浪高、地质复杂、冲刷严重、航道等级高、有效作业时间短。为适应该桥桥址气象、水文、地质等条件,考虑通航安全、技术可行及工程经济性等要求,确定采用高桩承台方案,并对φ3.0m、φ4.0m、φ4.5m钻孔桩基础方案进行比选,确定选用φ4.5m钻孔桩基础方案,按先平台后吊箱围堰的顺序施工。大直径桩基础中各桩采用单独配筋设计;防撞结构由吊箱围堰、V形防撞梁及联结系组成,采用可拆卸式设计,并在围堰外壁设置消波孔;钻孔桩采用KTY5000型动力头钻机,并配制PESF935型中压空压机循环排渣,利用泥浆护壁、锲齿或球齿滚刀钻头钻具切削岩面成孔;采用内径406 mm的单导管法施工水下C45混凝土。%The Guyumen Channel Bridge of the Pingtan Strait Rail‐cum‐Road Bridge adopts the scheme of a steel truss hybrid girder cable‐stayed bridge with a main span of 364 m .The construc‐tion of the bridge is constrained by the complex geological and hydrological conditions at the bridge site ,including deep water ,strong currents ,heavy winds ,hazardous torrents ,high tides and tur‐bulent waves ,severe scour ,high grade of navigational channel and tight efficient operation time . To suit the meteorological ,hydrological and geological conditions at the bridge site ,by considering the safety and technical feasibility and engineering economy ,it was determined that the elevated pile cap scheme be adopted .The pile foundations formed of bored piles respectively with 3 .0 m , 4 .0 m and 4 .5 m diameters were compared ,and the foundation scheme of 4 .5 m diameter bored piles was finally chosen .The foundation was constructed following the sequence of constructing the platform first and then the suspended box cofferdam .For the

  11. Generalized fragility curves for bearing-supported skew bridges, for arbitrary angle of incidence of the seismic action

    OpenAIRE

    Moschonas, I. F.; Kappos, A. J.

    2011-01-01

    In a previous work by the authors and their co-workers an analytical methodology for the derivation of seismic fragility curves for bridges was proposed. Bridges were classified into three main categories according to their seismic energy dissipation mechanism: bridges with yielding piers of the column type, bridges with bearings and non-yielding piers of the wall type, and bridges with bearings and yielding piers of the column type. Then, damage states were defined using deck displacement at...

  12. 高墩大跨连续刚构桥顶推合龙控制技术研究%Study of Control Techniques for Closure of Long-Span Continuous Rigid-Frame Bridge with High-Rise Piers by Pushing

    Institute of Scientific and Technical Information of China (English)

    魏建斌; 魏家乐; 马玲

    2014-01-01

    高墩大跨连续刚构桥通常采用悬臂浇筑法施工,合龙控制难度较大,以国家高速公路包头至茂名线(G65)陕西境内铜川至黄陵公路某连续刚构桥为背景,对顶推合龙控制技术进行研究。结合顶推合龙的关键工序及要求,采用有限元软件建立该桥有限元模型,计算收缩徐变、高温合龙产生的墩顶顺桥向位移规律和墩身刚度、约束情况对顶推力的影响规律,得到收缩徐变和高温合龙会造成梁体缩短和墩顶顺桥向位移,合龙前进行顶推可有效解决该问题;顶推力受墩身刚度、约束情况的影响较大,也将产生较大的结构响应,应进行严格控制;依据分析结果及相关经验确定了合理的顶推力及合龙控制参数。控制结果表明:顶推合龙技术有效达到了补偿收缩徐变和高温合龙产生的顺桥向位移的目的,该桥最终合龙误差满足要求,控制精度较高。%Long-span continuous rigid-frame bridges are usually constructed by cantilever cast-ing method , w hich brings great challenges to the control of closure . A continuous rigid-frame bridge on the Tongchuan to Huangling Highway in Shaanxi Province which belongs to part of the Baotou-Maoming National Highway (G65) was taken as the background to study the control tech-niques for the closure of the bridge of this type by pushing .Combined with the key construction procedure and demands of the closure carried out by pushing ,the finite element software was used to build the finite element model of the bridge ,so as to calculate the law of pier top displacement along the bridge length under the effect of concrete shrinkage and creep and high-temperature clo-sure as well as the influential law of the pier shaft stiffness and constraint condition on the pushing force .It is concluded that concrete shrinkage and creep and high-temperature closure can result in the girder shortening and pier top displacement

  13. 粘钢加固损伤混凝土箱型桥墩的抗震性能Ⅰ:双向拟静力试验%Anti-seismic properties of damaged concrete bridge piers with hollow box-section strengthened with adhering steel plates Ⅰ:bi-directional quasi-static test

    Institute of Scientific and Technical Information of China (English)

    宗周红; 邓江东; 黎雅乐; 刘爱荣

    2013-01-01

    11 scaled models of reinforced concrete bridge piers with hollow box-section were de-signed and fabricated in the lab.Bi-directional quasi-static tests for these scaled pier models strength-ened with adhering steel plates were carried out.Several seismic performance indicators, such as load-displacement hysteretic and skeleton curves, ductility, degradation of rigidity, and energy dissi-pation were investigated.The experimental results show that all the strengthened piers present typical flexural failure modes, and plastic hinge appears in the superior margin of steel plates in stead of in the bottom for piers without strengthening.The improvement of anti-seismic properties exhibits that it was an effective method to change the plastic hinge position by adhering steel plates.The load ca-pacity and the lateral rigid along the strong axis direction are greater, while the energy dissipation a-long the weak axis direction is stronger.The hysteretic curves of the weak axis exhibit notable pinch effects.The initial damage only has small effect on the degradation of rigidity and energy dissipation of the strengthening piers.Meanwhile, the changes of axial compression ratio and slenderness ratio have a great impact on the seismic performance.With the increase of the axial compression ratio, the carrying capacity, the ductility performance and energy dissipation of models increase, but the ulti-mate displacement decreases.With the decrease of the slenderness ratio, the carrying capacity of piers strengthened with adhering steel plates increases;however the ultimate deformation capacity de-creases, while the degradation of rigidity becomes more serious.%设计制作了11个钢筋混凝土箱型截面桥墩缩尺模型,对其进行了粘钢加固后的双向拟静力试验,分析了加固桥墩的荷载位移滞回曲线、骨架曲线、延性能力、刚度退化和耗能能力等。结果表明,加固墩柱均发生以弯曲破坏为主的延性破坏,破坏塑性

  14. 可液化场地桥梁群桩-独柱墩结构地震反应振动台试验研究%Shaking table tests for seismic response of pile-supported bridge structure with single-column pier in liquefiable ground

    Institute of Scientific and Technical Information of China (English)

    唐亮; 凌贤长; 徐鹏举; 高霞; 王东升

    2009-01-01

    针对两种土层结构的可液化场地条件,采用2×2低承台群桩一独柱墩结构形式,完成了两个试验体的群桩-独柱墩结构地震反应振动台试验,很好地再现了自然地震触发场地液化及结构反应的各种宏观现象.结果表明,桩的最大加速度反应位置与地层结构关系密切且随场地液化发展而不断变化;低承台条件下,三层土场地较二层土场地对墩顶的加速度反应放大作用更显著;场地液化过程中,承台附近或液化与非液化土层分界处桩发生最大或较大动应变;低承台下,二层土场地中柱墩反应较小、桩反应较强,三层土场地中柱墩反应较强.%Two shaking table tests for seismic pile-soil-bridge interaction in liquefiable ground, with a low-cap 4-pile group and two typical soil profiles, were performed. The tests reproduced the macroscopic phenomena of soil liquefaction and seismic response of the structures in liquefiable ground. It is observed that the portions of the piles with maximum acceleration were in close contact with the soil layers and varied with the development of soil liquefaction. For the low-cap pile-supported bridge structure, the ground with three soil layers exerted more significant amplification effect on the acceleration response of the pier top than the ground with two soil layers. During soil liquefaction, the strains of the piles near the cap and the soil interface between liquefied soil and non-liquefied soil were comparatively greater than those at other positions. For the low-cap pile groups, the response of the pier was comparatively less significant and the pile strongly responded to the input motion of the ground with two soil layers, while the response of the pier was more significant under input motion of the ground with three soil layers.

  15. Nonlinear Seismic Response Characteristics of Bridge with Double-column High-rise Piers Considering Pounding Effect%考虑碰撞效应的双柱式高墩桥梁非线性地震反应特性研究

    Institute of Scientific and Technical Information of China (English)

    高玉峰; 蒲黔辉; 李晓斌

    2011-01-01

    以西南山区线路中常用的双柱式高墩桥梁为研究对象,建立典型桥跨结构的空间动力分析模型,采用非线性动力时程分析方法,详细研究了考虑地震碰撞效应时桥梁结构的地震响应特性,并探讨了接触单元刚度取值、间隙宽度、桥台刚度以及支座滑动性能等非线性边界条件的影响.结果表明:梁间碰撞作用主要发生在近桥台伸缩缝处,碰撞作用减小桥墩的地震响应,同时在梁体中产生较大的短时加速度脉冲效应;考虑桥台的纵向约束作用将使得梁间碰撞效应增强;对于通常设计采用的间隙宽度范围,强震作用时碰撞现象会不可避免地发生;支座滑动性能对桥墩的地震响应起到隔震的作用,考虑支座滑动性能后梁间碰撞次数减少;各种非线性边界条件因素的综合作用使得桥跨结构的地震响应变得较为复杂,为获得结构真实响应结果应该合理考虑这些因素的影响.%Based on the double-column highway bridges with high-rise piers in southwest mountain area, the spatial dynamic analysis models of representative bridge span were established. The seismic response characteristics of the bridge considering the pounding effect were studied in detail by using nonlinear dynamic time history analysis method. The influence of some nonlinear boundary conditions, including value of contact element stiffness, gap width, abutment stiffness and sliding performance of bearings, were discussed. The results indicate that ( 1 ) the seismic pounding effect between adjacent beams occurs mainly in the expansion joint near the bridge abutments, the pounding reduces the seismic response of piers but generates high magnitude and short duration acceleration pluses in the beams; (2) the pounding effect between adjacent beams will be enhanced when the longitudinal constraint effect of abutments is considered; (3) for the range of gap width usually· adoptod in design, the pounding

  16. 基于支持向量机的高墩大跨桥梁体系可靠度计算%Computation of Structural System Reliability of High-Rise Pier and Long Span Bridge Based on Support Vector Machine

    Institute of Scientific and Technical Information of China (English)

    张士福; 康海贵; 郑元勋; 李玉刚

    2012-01-01

    为解决高墩大跨桥梁结构体系可靠度求解过程中失效模式复杂、极限状态方程无法显式表达等问题,提出一种基于支持向量机(SVM)分类技术的体系可靠度计算方法.该方法采用拉丁超立方抽样法产生样本库,通过重复筛选构造一个精确的SVM分类器函数(而不是构造功能函数本身的响应面函数),然后采用蒙特卡罗法进行数值模拟计算体系失效概率.以济邵高速公路逢石河特大桥为例验证了采用该方法计算高墩大跨桥梁体系可靠度的实用性,计算结果表明该桥体系可靠度满足设计要求.%To cope with the problems that the failure modes in the solving process of structural system reliability of high-rise pier and long span bridge are complicated and the limit state e-quations can not be displayed and expressed, a method for computation of the system reliability based on the support vector machine (SVM) classification technique is proposed. The proposed method can generalize the sample bank, using the Latin hypercube sampling method and can construct a precise SVM classifier function (rather than the response surface function of the structure function itself) by repeated screening and the numerical simulation and computation of the system failure probability are accordingly carried out, using the Monte Carlo method. By way of example of the Fengshi River Bridge on Jiyuan-Shaoyuan Expressway, the practicability of the method for computation of the system reliability of the high-rise pier and long span bridge is verified and the results of the computation prove that the system reliability of the bridge can meet the design requirements

  17. Scheme Comparison on Ship Anti-collision System for the Main Pier of Guan River Super Large Bridge in the Newly-built Lianyungang-Yancheng Railway%新建连盐铁路灌河特大桥主墩防船撞系统方案比选

    Institute of Scientific and Technical Information of China (English)

    周衍领

    2016-01-01

    Combined with the characteristics of the main pier structure in the water of Guan River Super Large Bridge in the newly-built Lianyungang-Yancheng Railway,as well as the meteorological,hydrological and geological conditions of the bridge location,navigable condition,and the harbor planning,three kinds of schemes on ship anti-collision system are de-signed for Guan River Super Large Bridge.The above schemes are introduced in detail,and the advantages and disadvanta-ges of each scheme are analyzed and compared.By scheme comparison,a ship anti-collision system suited for the charac-teristics of the structure of Guan River Super Large Bridge is finally determined.%结合新建连盐铁路灌河特大桥水中主墩结构特点,以及桥位处气象、水文、地质条件、通航条件、港口规划,为灌河特大桥设计了3种防船撞系统方案,对各防船撞系统方案进行了详细介绍,并进行了优缺点分析和对比。通过方案对比,最终确定了一种适合连盐铁路灌河特大桥结构特点的防船撞系统。

  18. Impact Analysis of the Bridge Pier Anti-collision Floating Box Sets Made by Sandwich Structure with Curved-shaped%夹层结构曲面环形浮式桥墩防撞套箱碰撞分析∗

    Institute of Scientific and Technical Information of China (English)

    许薛军; 单成林

    2015-01-01

    To improve the crashworthiness of bridge piers,a new type of annular anti-collision box with curved-shaped made by steel-polyurethane-steel sandwich plate was proposed.Using the ANSYS/LS-DYNA software with explicit dynamic transient nonlinear,the simulation model of ship collision with pier was established.This paper ana-lyzes the energy conversion between the ship,the anti-collision box,the rubber fender and the pier with the changes of the impact force and the speed of the ship in impact process.It also analyzed the stress and deformation of impact parts of anti-collision box.The results show that the bridge pier's annular anti-collision box with curved-shaped made by the sandwich plate can absorb 70% of the ship impact energy when the anti-collision box is unfavorably impacted, and that the anti-collision box has a saving stiffening plates and brackets,simple structure,and light weight.The study not only shows that the anti-collision box can fully play the impact property and excellent elastoplastic property of the sandwich plate itself,but also provides a theoretical basis for its engineering application.%针对船舶撞击桥梁的安全问题,提出一种钢聚氨酯钢夹层板制作的新型曲面环形浮式桥墩防撞套箱。采用显式动力瞬态非线性有限元软件 ANSYS/LS-DYNA 建立了船舶撞击桥墩的仿真模型,通过撞击过程中船舶撞击力和速度的变化,分析了船舶、防撞套箱、橡胶护舷、桥墩之间的能量转换以及防撞套箱撞击部位的受力和变形。研究表明:当防撞套箱受最不利撞击时,夹层板曲面环形桥墩防撞套箱能吸收70%的船舶撞击能量,且具有节省箱内加劲板及支架、构造简单、质量轻等特点。本文提出的桥墩防撞套箱具有良好的抗冲击性能和弹塑性能,为工程应用提供了理论依据。

  19. Numerical and Experimental Study on Seismic Performance of Bridge Piers by Steel Fiber Reinforced Concrete%钢纤维混凝土桥墩抗震性能数值模拟与试验

    Institute of Scientific and Technical Information of China (English)

    张于晔; 魏红一; 袁万城

    2013-01-01

    基于纤维模型的有限元分析技术,采用考虑钢纤维影响的混凝土材料模型和考虑黏结-滑移效应的钢筋材料模型,建立了在反复荷载作用下普通混凝土和钢纤维增强混凝土桥墩的非线性有限元模型.采用数值分析方法得到钢纤维体积分数、配箍率和钢纤维混凝土区高度对钢纤维混凝土桥墩模型滞回曲线、骨架曲线和延性性能等抗震能力的影响规律,并与试验结果进行了对比.结果表明:数值模拟与拟静力试验结果基本一致,呈现出相似的规律性;钢纤维可部分代替箍筋的抗震作用,在一定范围内随着钢纤维体积分数的增加,桥墩试件的抗震性能增强;在桥墩局部采用钢纤维混凝土,可达到与整体采用钢纤维混凝土相近的抗震能力.%The nonlinear finite element models of concrete piers under cyclic loading were established with the analytical method of fiber model.The concrete material model with a consideration of the effect of steel fiber and the steel material model with a consideration of the bond-slip effect were adopted.The influences of steel fiber volume fraction,stirrup ratio and the height of steel fiber reinforced concrete(SFRC) region on seismic capacity of the piers,such as hysteretic characteristics,skeleton curves and ductility,were obtained by the numerical analysis.The comparison numerical results were compared with the test results.The results show that the simulation results of seismic response are basically identical with the pseudo-static test results; parts of the stirrups' roles of seismic resistance can be substituted by the addition of steel fibers,and the seismic capacity of concrete piers is improved with the increase of steel fiber content in a certain range; similar seismic capacity can be sustained when the piers are constructed with a local or a whole application of SFRC.

  20. Effects of Multiple-mode Vibration on Elastic-plastic Seismic Responses of High Flexible Piers of Railway Bridge%多振型效应对铁路高柔桥墩弹塑性地震响应的影响

    Institute of Scientific and Technical Information of China (English)

    李宇; 朱晞; 杨庆山

    2011-01-01

    Nonlinear static analysis considering multiple-mode effects in FEMA356 and ATC-40 is improved. Basing on the capacity spectrum method (CSM) of soil-structure interaction effects (SSI) in FEMA440, taking the piers of one extra-long bridge of a railway line in southwest of China as the object of research and choosing eighty strong ground motion records in agreement with stipulations of site H specified in the Code of Seismic Design for Railway Engineering, the ductility and performance points of high flexible piers are solved by using the modified acceleration-displacement response spectrum (MADRS) locus of possible performance points introduced in FEMA440. From nonlinear time history analyses, the rationality and feasibility of the improved nonlinear static analysis method considering multiple-mode effects is verified by comparing with the average of seismic responses. The practicability of CSM considering SSI for railway bridge aseismic assessment is also verified.%对FEMA356和ATC-40中考虑多自度效应的非线性静力分析法进行改进.并在FEMA440考虑土-结构相互作用能力谱法基础上,以我国西南某铁路特大桥桥墩为研究对象,选取与我国《铁路工程抗震规范》Ⅱ类场地相符合的80条强震记录,利用FEMA440性能点轨迹法求解高柔桥墩结构延性及性能点;并与80条强震记录非线性时程分析计算结果平均值进行比较.验证本文改进的非线性静力分析法反映高柔桥墩多自度效应的合理性,及考虑土-结构相互作用能力谱法在铁路桥梁工程中应用的可行性.

  1. Docks and Piers, Fishing Piers in, Published in unknown, Manatee County Information Services Dept..

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset as of unknown. It is described as 'Fishing Piers in'. Data by this publisher are often provided in State Plane coordinate system; in a...

  2. Brief Discussion on Anti-collision Design Example for Piers of Rugao Changqingsha Bridge%浅谈如皋市长青沙大桥桥墩防撞设计实例

    Institute of Scientific and Technical Information of China (English)

    魏东海; 张兆民

    2011-01-01

    With the continuous emergence of large-size bridge along Changjiang water area and rapid increase of ship quantity and tonnage,the safety control project design for navigation span of Rugao Changqingsha Bridge of dredging harbor highway are made to ensure the safety of ship's navigation and bridge facilities.%随着沿长江水域大型桥梁的不断涌现以及船舶数量、吨位的快速增加,为有效保障船舶航行和桥梁设施安全,进行了如皋市疏港公路长青沙大桥通航孔安全保障工程的设计。

  3. MULTIPHASE BLASTING OF THE BRIDGE ACROSS THE DRENICA RIVER

    OpenAIRE

    Branko Božić

    1989-01-01

    The construction of new bridges on the sites of the existing ones require demolition of the old bridge. Due to closeness of newly erected bridge elements the fundations of old bridges are demolished by multiphase blasting process. The blasting of the piers and anchorages of the bridge across 'the Drenica river carrying the Balačevac—Goleš industrial railway was done in four phases. The piers and anchorages of a new bridge and its construction elements have been erected before (the paper is pu...

  4. Analysis and Verification of Local Stress on Pier-Tower-Girder Fixed Segment of High-Speed Railway Low-pylon Cable-stayed Bridge%高速铁路矮塔斜拉桥墩塔梁固结段局部应力分析与验证

    Institute of Scientific and Technical Information of China (English)

    邓江涛

    2016-01-01

    Local analysis is an important method often used in bridge design and also an indispensable part of the design. The solid finite element model is used to reflect in detail the local stress of structures, playing a guiding role in investigating real stress state of important structures and in the design of reinforcement. In order to investigate real stress state of the pier-tower-girder fixed segment of the prestressed concrete low-pylon cable-stayed bridge and verify the accuracy of local boundary condition analysis, a refined space solid finite element model is established and the accuracy of local boundary condition analysis is verified with reference to a (115+95)m unballasted double line prestressed concrete low-pylon cable-stayed bridge on Beijing-Shenyang dedicated passenger line. The analysis shows that the pier-tower-girder fixed segment experiences a stress concentration at the hole, where reinforcement should be strengthened appropriately, and the stress on the remaining parts meets the requirement. The accuracy of resulted stress is guaranteed by validation of the local model’s internal force transmission and support reactions, and structural safety is ensured. Finally, a typical local analysis method is concluded, which may provide some references for other local stress analysis.%局部分析是桥梁设计中常采用的重要手段,也是设计中不可或缺的重要环节,利用实体有限元模型能反应出结构细部的受力状况,对考察结构重要部位的真实应力状态、结构设计配筋有着指导性作用。为了解高速铁路矮塔斜拉桥墩塔梁固结段的真实应力状态及验证局部分析中边界条件表达的准确性,以京沈客运专线(115+95) m双线无砟轨道预应力混凝土矮塔斜拉桥为工程背景,利用Ansys有限元建立细化的空间实体有限元模型,并对局部模型的边界条件模拟的正确性进行验证,分析表明,墩塔梁固结段进人洞角点处应

  5. 公安长江公铁两用特大桥4号墩基础施工关键技术%Key Techniques for Construction of Foundation of Pier No .4 of Gong′an Changjiang River Rail-cum-Road Bridge

    Institute of Scientific and Technical Information of China (English)

    房保华

    2015-01-01

    T he main bridge of Gong′an Changjiang River Rail‐cum‐Road Bridge is a steel truss girder cable‐stayed bridge with double pylons and with span arrangement (98+182+518+182+98) m .The foundation of Pier No .4 of the bridge is the one of bored piles plus pile cap ,of which the piles are in variable diameters of 2 .8 m/3 .1 m ,the numbers of the piles are totally 36 and the pile cap ,designed in the rounded end shape ,is 58 .4 m long ,33 .6 m wide and 6 m high and is em‐bedded in the riverbed .The foundation of the pier was constructed by the scheme of double‐wall steel boxed cofferdam in the sequence that the cofferdam was set up first ,the working platform was late ,the boring of the piles was carried out first and the base sealing of the cofferdam was late and the pile cap was concreted finally .In the construction of the foundation ,the following key techniques were applied .The first lift of the cofferdam (68 .2 m long ,40 m wide and 16 m high) was integrally launched to the river by the air bag method .The first lift of the cofferdam ,the in‐ternal support trusses of the cofferdam and the steel casings at the pier site were used to form a semi‐floating boring platform .The bored piles were constructed by the air lifting reverse circula‐tion boring aided by the bored hole wall mud protection .At the time the construction of the bored piles was completed ,the cofferdam was lowered down ,the height of the cofferdam was extended , the water was pumped into the cofferdam ,the dredging inside the cofferdam was carried out and the cofferdam was sunk down .After the cofferdam was sunk down in place to the designed eleva‐tion and the base of the cofferdam was sealed in areas .The water inside the cofferdam was pumped out and the pile cap was finally concreted in two layers according to the workmanship of massive concrete .%公安长江公铁两用特大桥主桥为(98+182+518+182+98) m双塔钢桁梁斜拉桥,该桥4号主墩采用2.8m

  6. Shaking Table Tests of Curved Bridge considering Bearing Friction Sliding Isolation

    Directory of Open Access Journals (Sweden)

    Lei Yan

    2016-01-01

    Full Text Available Specific to severe damage to curved bridges in earthquakes caused by the excessive force of the fixed bearings and piers, a new seismic design method on curved bridges considering bearing friction sliding isolation is proposed in this paper. Seismic model bridge and isolation model bridge with similarity ratio of 1/20 were made and the shaking table comparison test was conducted. The experimental results show that the isolation model curved bridge suffered less seismic damage than the seismic model curved bridge. The fundamental frequencies of the seismic model bridge and isolation model bridge decreased and the damping ratio increased with the increase of seismic intensity. Compared with seismic curved bridge, the maximum reduction rates of peak acceleration along the radial and tangential directions on the top of pier of the isolation model curved bridge were 47.3% and 55.5%, respectively, and the maximum reduction rate of the peak strain on the bottom of pier of the isolation model curved bridge was 43.4%. For the isolation model curved bridge, the maximum reduction rate of peak acceleration on the top of pier was 24.6% compared with that on the bottom of pier. The study results can provide experimental basis for the seismic design of curved bridges.

  7. MPA 方法在不同高度桥墩地震响应分析中的适用性研究%Application of Modal Pushover Analysis Method to Seismic Response of Piers with Different Heights

    Institute of Scientific and Technical Information of China (English)

    蒋崇文; 王典斌; 卢皓

    2015-01-01

    Bridges are usually lifeline engineering-in-traffic projects,and their seismic performance is very important.As an important bridge construction component,piers are vulnerable to dam-age under strong ground motion.In this paper,in accord with the typical pier structure form of bridge piers in mountainous areas,a nonlinear numerical analysis model is constructed based on a fiber model.The seismic response of different piers under El-Centro is performed using modal pushover analysis (MPA).By comparison with the nonlinear time history analysis method,the applicability of the MPA method for the seismic analysis of different piers is investigated.The results show that the MPA method is not suitable for higher piers where the contribution of higher modes in seismic response is significant.With the implementation of the Western Develop-ment Program in recent years,a lot of highways and railways have been planned and built in western China.For bridges with high piers in mountainous areas,a nonlinear numerical analysis model is constructed based on a fiber model.The finite-element analysis is simulated with the code Open Sees,which was developed by Pacific Earthquake Engineering Research (PEER).The Mander model is used to imitate the constitutive model of concrete,and the Giuffré-Menegotto-Pinto model is used to imitate the constitutive model of reinforcement.The incremental dynamic analysis is used to research distribution features of pier section curvature under strong earthquake motions.As a result of the effects of higher modal contributions,the seismic response and seis-mic performance of bridges with high piers are complicated.The forming and development of a plastic range in the upper position of a pier,the damage process,and the failure mechanism of high piers under different earthquake motions are studied.The base section curvature of high piers and its top displacement are not simultaneous;it is inappropriate for pier top displacement to be used as the

  8. 连续梁墩柱合理设计的影响因素分析%Factor Analysis of Continuous Beam Pier Columns Rational Design

    Institute of Scientific and Technical Information of China (English)

    张帅; 肖锋文; 赵杰丽

    2012-01-01

    随着连续梁桥的广泛应用,连续梁桥墩柱的合理设计值得深入研究.从影响连续梁桥墩柱设计的主要因素出发,深入分析各影响因素的重要性,为连续梁桥墩柱合理设计提供参考.%With the wide application of the continuous beam bridge, the rational design of continuous beam pier column worthy of further study. In this article, starting from the main factors affecting the continuous beam bridge pier column design. In-depth analysis of the importance of each factor in order to give reference for the rational design of continuous beam bridge pier column.

  9. Ultimate Flexural Capacity of Unbounded Prestressed Concrete Pier

    Directory of Open Access Journals (Sweden)

    Wang Hui-li

    2014-01-01

    Full Text Available Based on the plastic-hinge method, the influence of different factors on the ultimate flexural capacity is analyzed, including relationship between the ultimate bearing capacity and prestressing tendon area, the regular reinforcement area, the strength of concrete and other influence factors. The results show that, the increase in the area of regular reinforcement and the strength of concrete can enhance the ultimate flexural capacity. Moreover, the ultimate bending moment increases first and then decreases, with the increasing of the prestressing tendon. Thus, the most effective method to increase the ultimate flexural capacity of prestressed concrete bridge pier is to increase regular reinforcement ratio, and to control the number of prestressing tendon simultaneously.

  10. General design of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Yuan Hong; Pei Minshan; Dai Jie; Xu Lin

    2009-01-01

    The main span of Sutong Bridge is a double-pylon, double-plane cable-stayed bridge with steel box girder, which has the world's longest central span of 1 088 m within cable-stayed bridges. To overcome problems caused by severe meteorological conditions, perplexing hydrological conditions, deep buried bedrock and higher navigation level, many new technics and methods were created. Keys including structural system, steel box girder, stayed cable, tower, pier, tower foundation, collision avoidance system, wind-resistance, seismic-resistance, structural nonlinear response and structural static stability were presented individually in this paper.

  11. 安庆长江铁路大桥3号墩围堰锚碇系统设计与施工%Design and Construction of Mooring System for Cofferdam of Pylon Pier No.3 of Anqing Changjiang River Railway Bridge

    Institute of Scientific and Technical Information of China (English)

    刘爱林; 农代培

    2011-01-01

    The bored pile foundation of pylon pier No. 3 of Anqing Changjiang River Railway Bridge was constructed with the circular double-wall steel boxed cofferdam. To realize the accurate positioning and construction safety of the cofferdam, through comparison of the different schemes, it was decided that the cofferdam would be positioned by the mooring system from the front and rear positioning barges without utilizing guiding barge. The types and numbers of the mooring anchors, the mooring ropes and positioning barges were determined according to the calculation of the total tensile force of the main anchors and the force of each anchor after sinking thecofferdam in place. In the design, the problem of steering and reeling of the large diameter mooring ropes was tackled by the tie points on the sides of the cofferdam and by the one-way or multi-way rolling fairleaders set at the top of the cofferdam. The side anchors were heaved by the winches installed on the anchor weighing platforms on the front and rear positioning barges and at the top of the cofferdam and the anchors could be therefore cast, weighed and changed. The side anchors on the shore and ground anchors were embedded in the excavated pits and the anchors under water were cast by the 240 t barge. The mooring ropes were timely tied, untied, tightened and the anchors were adjusted in pace of sinking of the cofferdam to finally complete the construction of the mooring system.%安庆长江铁路大桥3号桥塔墩钻孔桩基础采用圆形双壁钢套箱围堰施工.为实现围堰的精确定位和施工安全,经方案比较采用无导向船的前、后定位船锚碇系统定位方案,锚型与数量、锚绳及定位船通过计算围堰下沉到位后主锚总拉力及各锚碇受力确定.设计中通过在围堰侧面的边锚拉结点及围堰顶面设置单向或多向转动的辊轴式马口解决大直径锚绳转向和收放难题;通过在前、后定位船和围堰顶的收锚平台上安装

  12. Nondestructive evaluation techniques for enhanced bridge inspection

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.; Benson, S.; Durbin, P.; Del Grande, N.; Haskins, J.; Brown, A.; Schneberk, D.

    1993-10-01

    Nondestructive evaluation of bridges is a critical aspect in the US aging infrastructure problem. For example in California there are 26,000 bridges, 3000 are made of steel, and of the steel bridges, 1000 are fracture critical. California Department of Transportation (Caltrans), Federal Highway Administration, and Lawrence Livermore National Laboratory (LLNL) are collaborating to develop and field NDE techniques to improve bridge inspections. We have demonstrated our NDE technologies on several bridge inspection applications. An early collaboration was to ultrasonically evaluate the steel pins in the E-9 pier on the San Francisco Bay Bridge. Following the Loma-Prieta earthquake in 1989 and the road way collapse at the E-9 pier, a complete nondestructive evaluation was conducted by Caltrans inspectors and several ultrasonic indications were noted. LLNL worked with Caltrans to help identify the source of these reflections. Another project was to digitally enhance high energy radiographs of bridge components such as cable end caps. We demonstrated our ability to improve the detection of corrosion and fiber breakage inside the end cap. An extension of this technology is limited view computer tomography (CT). We implemented our limited view CT software and produced cross-sectional views of bridge cables from digitized radiographic films. Most recently, we are developing dual band infrared imaging techniques to assess bridge decks for delaminations. We have demonstrated the potential of our NDE technology for enhancing the inspection of the country`s aging bridges.

  13. 高桥墩的稳定性计算%Calculating on stability of high pier

    Institute of Scientific and Technical Information of China (English)

    李轲

    2009-01-01

    通过对桥梁高桥墩边界条件的分析,建立了以板式橡胶支座为弹性支承的压杆计算模型,导出了在该计算模型下结构临界荷载的计算公武,通过对广东北江特大桥主墩进行稳定性分析和墩身参数分析,得到了桥墩高度与稳定系数的对应关系,对今后类似的设计工作有一定的参考作用.%Through analyzes the limit situation of high pier, the paper establishes rubber bearing plate in elastic support for the calculation mod-el of the bar, derives calculating formula of structure's limit loading ability under the mode. Through analysis on stability and pier body's pa-rameter of Beijiang super huge bridge in Guangdong, it derives relationship between height and stability of the pier, and thus provides guidance for such kind of construction.

  14. FBG sensor networks for the estimation of boundary shear stress around the novel piers

    Science.gov (United States)

    Lü, Chengang; Zhang, Ruifeng; Li, Kejia; Wu, Xing; Ge, Chunfeng

    2010-10-01

    The paper reports results obtained from a field test site in structural monitoring-a "test-to-failure," measuring strain using Fiber Bragg gratings (FBGs) sensor networks on a novel drilled concrete test pier in Huaihe river zone,Anhui province,China. To undertake the study, FBG-based sensors were chosen ,metallic recoated ,steel-tube packaged , and incorporated with steel rebars in this concrete structure. The sensors were interrogated using a compact system based on wavelength-division multiplexing (WDM) and F-P scanning approach. Throughout the test, the FBG sensors were continuously monitored, the incremental increases in the strain caused by boundary shear stress could be seen. The sensors were able to follow the resulting induced changes in load of over a range in excess of 2.5M Newton just prior to failure of the pier and representing extreme levels of strain for such a novel mechanical structure. The measurements made with the FBG-based system were found to be in agreement with the changes expected in the structure, produced by the self-balanced loading applied. The study has demonstrated the successful use of FBG sensor networks used in a test of this root type pier foundation, consequently made assessment about the health and security of the highway bridge.

  15. Structural safety monitoring for Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    黄方林; 何旭辉; 陈政清; 曾储惠

    2004-01-01

    In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.

  16. Abutments influence in the dynamic response of bridges

    OpenAIRE

    Martínez Cutillas, Antonio; Gómez Lera, Sagrario; Alarcón Álvarez, Enrique

    1996-01-01

    A simplified analytical model of a short span bridge is proposed. The inertial interaction effects of pier foundations and abutments has been included in order to evaluate the response sensitivities to different soil-structure interaction variables. The modification of natural frequency and damping properties is shown for typical short span bridges of the integral deck-abutment type for longitudinal vibrations or general bridges for the transverse ones.

  17. Effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge

    Directory of Open Access Journals (Sweden)

    Wang Changfeng

    2014-10-01

    Full Text Available During an earthquake, the nonlinearity of the bridge structure mainly occurs at the supports, bridge piers and restrainers. When entering nonlinear stage, members of the bridge structure affect the elasto-plastic seismic response of the whole structure to a certain extent; for multi-span continuous bridges, longitudinal restrainers can be installed on the movable piers to optimise the distribution of seismic force and enable the movable piers to bear a certain amount of seismic effect. In order to evaluate the effect of nonlinearity of restrainer and supports on the elasto-plastic seismic response of continuous girder bridge, analytical models of continuous girder bridge structure considering the nonlinearity of movable supports, restrainers and bridge piers were built and the nonlinear time history analysis was conducted to evaluate the effect of nonlinearity of restraining devices and supports on the elasto-plastic seismic response of continuous girder bridge. Relevant structural measures and recommendation were made to reduce the seismic response of the fixed piers of the continuous girder bridge.

  18. Scour and Scour Countermeasures at Bridge Sites

    Institute of Scientific and Technical Information of China (English)

    CHIEW Yee-Meng

    2008-01-01

    This paper examines scour and scour countermeasures at bridge piers and abutments.Abutment scour is by far more complex than its counterpart associated with piers because of the possibility of the presence of a floodplain. Notwithstanding this, the mechanism of scour at both piers and abutments is very similar; moreover, the failure mechanisms associated with both armor-ing and flow-altering countermeasures are not very different. In rivers with a floodplain, abutment scour becomes much more complex. In cases where the abutment ends at or near to the flood-plain, it can initiate bank erosion, which clearly is an important erosion problem that is quite distinct from the customary scour at either an abutment in rivers without a floodplain or a pier. For this rea-son, abutment scour can be very site-specific while pier-scour is more generic in nature. To this end, the ability to identify the type of abutment scour that may form in a particular channel is closely related to an engineer's ability to propose devices for effective scour countermeasure.By summarizing research efforts on using riprap as a pier or abutment countermeasure over the past few decades, this paper highlights the deficiencies of riprap in arresting pier scour. To this end,different failure mechanisms are identified. They are shear failure, winnowing failure, edge failure,bedform-induced failure and bed-degradation induced failure. Each failure mechanism can singly or, more likely, combine to cause the eventual breakdown of the riprap layer. The study shows that a riprap layer is vulnerable to other failure mechanisms even though it is adequately designed against shear failure, rendering it ineffective in arresting scour.

  19. On Construction Technology of High Pier Sliding Model%浅谈高墩滑模施工技术

    Institute of Scientific and Technical Information of China (English)

    杨晓军

    2014-01-01

    With the development of economy, China's highway and bridge construction develop rapidly. In order to meet market demand, the bridge structure is now becoming more and more complicated, high pier bridge so does. At present, China's high highway usually through the mountainous and hilly areas with form of long tunnel, bridge with high pier and long span combined. Comparing the common template pouring, the pouring of concrete sliding model construction has good advantages of continuity, high speed, good quality, low consumption of materials etc. Combined with the potential problems of similar construction projects often appear like "terrain","construction period", "safety" and other problems, this paper discusses the high pier construction of Fenhe River Bridge, introduces the structural design calculation and load of high pier bridge pier sliding mode, analyses the measurement and correction measures for high pier bridge sliding model construction process, key points of quality control and assurance measures in detail, aims to improve the construction technology of sliding model construction in the future. And some corresponding policy suggestions are proposed so as to provide reference for high pier sliding model construction.%随着经济的不断发展,我国的公路、桥梁建设事业发展迅速。为了适应市场需求,如今的桥梁结构日趋复杂,高墩柱桥梁更是比比皆是。目前,我国高等级公路多采用长大隧道、高墩大跨度桥梁相结合形式穿越山岭重丘区。滑模施工浇筑混凝土相对于常规模板浇筑具有连续性好,进度快,质量好,材料消耗少等诸多优点。本文以汾河特大桥高墩施工为背景展开论述,结合同类建设工程中常出现的“地形复杂”、“工期紧张”、“安全风险大”等难题,对高墩柱桥梁墩柱滑模的结构设计及荷载计算做介绍,对高墩柱桥梁滑模施工过程中测量及纠

  20. Simulation of the Whole Process of Ship-Bridge Collision

    Institute of Scientific and Technical Information of China (English)

    刘建成; 顾永宁

    2002-01-01

    The simulation of the whole ship-bridge collision process can be effectively carried out by nonlinear dynamic finiteelement method. Based on the simple description of the theory, a scenario of a 40000 DWT oil tanker colliding with abridge across the Yangtze River is designed for simulation. The technology of structure modeling and the determination ofrelated parameters are introduced. The deformation of the bulb bow, the history of collision force change, the exchange ofcollision energy and the stress distribution of the bridge pier are described in detail, which are of great value to bridge de-sign and bridge pier damage estimation, Some mechanical characters in the process of ship-bridge collision are described.More accurate results can be produced by finite element method than that by empirical formulas and simplified analyticalmethods.

  1. Development and evaluation of clear-water pier and contraction scour envelope curves in the Coastal Plain and Piedmont Provinces of South Carolina

    Science.gov (United States)

    Benedict, Stephen T.; Caldwell, Andral W.

    2016-01-01

    The U.S. Geological Survey in cooperation with the South Carolina Department of Transportation collected clear-water pier- and contraction-scour data at 116 bridges in the Coastal Plain and Piedmont Physiographic Provinces of South Carolina. Pier-scour depths collected in both provinces ranged from 0 to 8.0 feet. Contraction-scour depths collected in the Coastal Plain ranged from 0 to 3.9 feet. Using hydraulic data estimated with a one-dimensional flow model, predicted clear-water scour depths were computed with scour equations from the Federal Highway Administration Hydraulic Engineering Circular 18 and compared with measured scour. This comparison indicated that predicted clear-water scour depths, in general, exceeded measured scour depths and at times were excessive. Predicted clear-water contraction scour, however, was underpredicted approximately 30 percent of the time by as much as 7.1 feet. The investigation focused on clear-water pier scour, comparing trends in the laboratory and field data. This comparison indicated that the range of dimensionless variables (relative depth, flow intensity, relative grain size) used in laboratory investigations of pier scour, were similar to the range for field data in South Carolina, further indicating that laboratory relations may have some applicability to field conditions in South Carolina. Variables determined to be important in developing pier scour in laboratory studies were investigated to understand their influence on the South Carolina field data, and many of these variables appeared to be insignificant under field conditions in South Carolina. The strongest explanatory variables were pier width and approach velocity. Envelope curves developed from the field data are useful tools for evaluating reasonable ranges of clear-water pier and contraction scour in South Carolina. A modified version of the Hydraulic Engineering Circular 18 pier-scour equation also was developed as a tool for evaluating clearwater pier

  2. 33 CFR 118.70 - Lights on swing bridges.

    Science.gov (United States)

    2010-07-01

    ... (draw pier protection piers) and each end of the piers protecting the pivot pier (pivot protection pier... side of the pivot pier and the channel side of each draw pier which has a protection pier will be... navigable channel passes on only one side of the pivot pier of any swing span, the District Commander...

  3. 78 FR 32274 - Scorpion Pier Replacement Project, Channel Islands National Park, Santa Barbara County, California

    Science.gov (United States)

    2013-05-29

    ... existing Scorpion Pier is a flatbed railcar that was installed as a temporary facility in 2000. The pier is... hazards and to perform required repair and maintenance activities. The pier sometimes cannot be used by... circulation; Frequent maintenance required to the pier access road, which threatens to expose or...

  4. Docks and Piers, Pier point, line, and polygon locations within Iredell County, NC, Published in 2005, 1:2400 (1in=200ft) scale, Iredell County GIS.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset, published at 1:2400 (1in=200ft) scale, was produced all or in part from Orthoimagery information as of 2005. It is described as 'Pier...

  5. A novel bridge scour monitoring and prediction system

    Science.gov (United States)

    Valyrakis, Manousos; Michalis, Panagiotis; Zhang, Hanqing

    2015-04-01

    Earth's surface is continuously shaped due to the action of geophysical flows. Erosion due to the flow of water in river systems has been identified as a key problem in preserving ecological health but also a threat to our built environment and critical infrastructure, worldwide. As an example, it has been estimated that a major reason for bridge failure is due to scour. Even though the flow past bridge piers has been investigated both experimentally and numerically, and the mechanisms of scouring are relatively understood, there still lacks a tool that can offer fast and reliable predictions. Most of the existing formulas for prediction of bridge pier scour depth are empirical in nature, based on a limited range of data or for piers of specific shape. In this work, the use of a novel methodology is proposed for the prediction of bridge scour. Specifically, the use of an Adaptive Neuro-Fuzzy Inference System (ANFIS) is proposed to estimate the scour depth around bridge piers. In particular, various complexity architectures are sequentially built, in order to identify the optimal for scour depth predictions, using appropriate training and validation subsets obtained from the USGS database (and pre-processed to remove incomplete records). The model has five variables, namely the effective pier width (b), the approach velocity (v), the approach depth (y), the mean grain diameter (D50) and the skew to flow. Simulations are conducted with data groups (bed material type, pier type and shape) and different number of input variables, to produce reduced complexity and easily interpretable models. Analysis and comparison of the results indicate that the developed ANFIS model has high accuracy and outstanding generalization ability for prediction of scour parameters. The effective pier width (as opposed to skew to flow) is amongst the most relevant input parameters for the estimation. Training of the system to new bridge geometries and flow conditions can be achieved by

  6. Cezi Island Crude Pier Put into Operation Successfully

    Institute of Scientific and Technical Information of China (English)

    Wang Jiangge; Liu Haijun; Diao Feng

    2006-01-01

    @@ On Feb. 25th, 2006, the 300,000-ton Cezi Island Pier,a State key construction project was finished. It began to receive crude oil smoothly. Cezi Island was one of the largest crude oil piers in China at present. Its putting into operation will enable the Ningbo - Shanghai - Nanjing pipeline network double its total transmitting capacity to reach 40 million tons a year.

  7. Pier Luigi Nervi architetture voltate Verso nuove strutture

    OpenAIRE

    Solomita, Pasqualino

    2012-01-01

    L’ingegner Pier Luigi Nervi (1891-1979), progettista, costruttore e teorico del “Costruire Correttamente”, ha intrapreso un proprio esclusivo percorso professionale che ha decretato negli anni una notevole fortuna critica fino a un sostanziale oblio dopo la sua morte. La presente ricerca di dottorato intende approfondire le tematiche legate a una significativa tipologia strutturale che ha contrassegnato il percorso professionale di Pier Luigi Nervi: le architetture voltate. Cupole, vol...

  8. Dynamic Soil-Structure Interaction in Bridge Abutments

    OpenAIRE

    Martínez Cutillas, Antonio; Mateo Bermejo, J.; Alarcón Álvarez, Enrique

    1996-01-01

    Strong motion obtained in instrumental short-span bridges show the importance of the abutments in the dynamic response of the whole structure. Many models have been used in order to take into account the influence of pier foundations although no reliable ones have been used to analyse the abutment performance. In this work three-dimensional Boundary Element models in frequency domain have been proposed and dimensionless dynamic stiffness of standard bridge abutments have been obtained.

  9. Aerodynamic stability of cable-stayed-suspension hybrid bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-jun; SUN Bing-nan

    2005-01-01

    Three-dimensional nonlinear aerodynamic stability analysis was applied to study the aerodynamic stability of a cable-stayed-suspension (CSS) hybrid bridge with main span of 1400 meters, and the effects of some design parameters (such as the cable sag, length of suspension portion, cable plane arrangement, subsidiary piers in side spans, the deck form, etc.) on the aerodynamic stability of the bridge are analytically investigated. The key design parameters, which significantly influence the aerodynamic stability of CSS hybrid bridges, are pointed out, and based on the wind stability the favorable structural system of CSS hybrid bridges is discussed.

  10. Study on the Spatial Stress of the Chongqing Yangtze River Bridge in China

    Directory of Open Access Journals (Sweden)

    Yan Li

    2014-09-01

    Full Text Available Continuous rigid-frame bridges are usually used in building bridges with long span and high piers. It is characterized by the consolidation between piers and beams in the middle of bridge piers and flexible bridge piers in the lower part. Among all the factors, curvature has the most obvious influence on the stress of curved continuous rigid-frame bridge, because of which, the curved beam bridge produces coupling effect of bending moment and receives complicated stress, leading to the deformation such as torsion and displacement of radial direction. No matter it is the castscaffold construction or cantilever construction, for continuous rigid-frame bridges, considering that after the long term creep of concrete, structure stress tends to be in a drop-frame state, so it is necessary to know the mechanical properties of the finished bridge. Taking the Chongqing Yangtze River Bridge as an example, this paper mainly analyzes the internal forces and deformations of a finished curved continuotus rigid-frame bridge by establishing a spatial finite element model with Midas Civil 2006 software and by changing the model’s radius of curvature. The results show that as the curvature increases, the vertical deformation and torsion angle of the long-span curved continuous rigid-frame bridge are both reduced under the effect of a dead load and prestressed load, presenting mechanical properties of bridge, namely, “coupling effect of bending moment”. In the model analyzed, the deformation of the bridge in the transverse direction also behaves a trend of gradual decrease with an increase in radius of curvature with the range 500–2000 m.

  11. Near-fault directivity pulse-like ground motion effect on high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 张楠; 蒋丽忠; 曾志平; 陈格威; 国巍

    2014-01-01

    The vehicle-track-bridge (VTB) element was used to investigate how a high-speed railway bridge reacted when it was subjected to near-fault directivity pulse-like ground motions. Based on the PEER NAG Strong Ground Motion Database, the spatial analysis model of a vehicle-bridge system was developed, the VTB element was derived to simulate the interaction of train and bridge, and the elasto-plastic seismic responses of the bridge were calculated. The calculation results show that girder and pier top displacement, and bending moment of the pier base increase subjected to near-fault directivity pulse-like ground motion compared to far-field earthquakes, and the greater deformation responses in near-fault shaking are associated with fewer reversed cycles of loading. The hysteretic characteristics of the pier subjected to a near-fault directivity pulse-like earthquake should be explicitly expressed as the bending moment-rotation relationship of the pier base, which is characterized by the centrally strengthened hysteretic cycles at some point of the loading time-history curve. The results show that there is an amplification of the vertical deflection in the girder’s mid-span owing to the high vertical ground motion. In light of these findings, the effect of the vertical ground motion should be used to adjust the unconservative amplification constant 2/3 of the vertical-to-horizontal peak ground motion ratio in the seismic design of bridge.

  12. 76 FR 1521 - Security Zone: Fleet Industrial Supply Center Pier, San Diego, CA

    Science.gov (United States)

    2011-01-11

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA87 Security Zone: Fleet Industrial Supply Center Pier, San... Fleet Industrial Supply Center Pier. The pier is no longer owned by the U.S. Navy and the existing... of the San Diego Bay, San Diego, CA. The existing security zone is around the former Fleet...

  13. 48 CFR 52.247-40 - Ex Dock, Pier, or Warehouse, Port of Importation.

    Science.gov (United States)

    2010-10-01

    ... Warehouse, Port of Importation. 52.247-40 Section 52.247-40 Federal Acquisition Regulations System FEDERAL... Provisions and Clauses 52.247-40 Ex Dock, Pier, or Warehouse, Port of Importation. As prescribed in 47.303-12..., pier, or warehouse, port of importation: Ex Dock, Pier, or Warehouse, Port of Importation (APR 1984)...

  14. Railroad Bridges

    Data.gov (United States)

    Department of Homeland Security — Bridges-Rail in the United States According to The National Bridge Inspection Standards published in the Code of Federal Regulations (23 CFR 650.3), a bridge isA...

  15. 18 CFR 1304.204 - Docks, piers, and boathouses.

    Science.gov (United States)

    2010-04-01

    ... structure of the maximum size, TVA shall determine the size of facility that may be approved. Applicants are... responsible for submitting plans for proposed docks, piers, and boathouses that conform to the size standards... structure. Access walkways to the water-use structure are not included in calculating the 1000-foot area....

  16. 车—桥碰撞的数值模拟研究%Research on numeric simulation of crash between vehicle and bridges

    Institute of Scientific and Technical Information of China (English)

    邓乙民; 刘吉波

    2012-01-01

    利用有限元分析软件ANSYS/LS-DYNA,建立了汽车—桥墩碰撞的有限元模型,通过对汽车—桥墩的碰撞过程进行数值模拟分析,得到了碰撞过程中的碰撞力、碰撞能量和桥墩墩顶位移,分析了桥墩受撞破坏的机理,对车—桥碰撞研究具有十分重要的意义。%The paper adopts the finite element analysis software,ANSYS/LS-DYNA,establishes the finite element model for the crash between the vehicle and bridge piers,analyzes the numeric simulation the crashing process between the vehicle and bridge piers,achieves the collision force,crashing energy and the displacement of pier top of the bridge piers,and analyzes the mechanism for the damage of the bridge piers,so as to have the important significance for the research on crash between vehicle and bridges.

  17. 考虑支座摩擦和墩柱损伤的桥梁用液体粘滞阻尼器参数确定方法%Parameter determination method for fluid viscous damper used in bridges considering bearing friction and pier damage

    Institute of Scientific and Technical Information of China (English)

    焦驰宇; 张恺; 张连普; 龙佩恒

    2013-01-01

    对桥梁阻尼器参数确定方法的相关文献进行了回顾,指出现有常用参数分析法费时费力;而简化分析法存在仅适用于结构保持在弹性阶段、无法考虑罕遇地震下支座摩擦及墩柱轻度损伤等复杂情况的弊端.以非线性静力分析获得的能力曲线为基础,利用性能点、目标点求解时获得的关键参数,结合等效弹性单自由度体系附加非线性粘滞阻尼器的参数确定公式,提出了考虑支座摩擦和墩柱损伤的桥用阻尼器参数确定方法.将该方法应用于某三跨连续梁桥抗震加固分析,验证了该方法的实用性及准确性.指出了该方法具有的优势及使用时需注意的问题.本文方法可用于中小跨径桥梁抗震加固时液体粘滞阻尼器的参数确定.%By reviewing parameter determination methods for fluid viscous damper ( FVD) applied in structural engineering, the defect of time consuming when using parameter analysis method, and the defect of not considering the bearing friction and other nonlinearity when using normal simplified method were pointed out. A new parameter determinations method which can easily and quickly consider the above effects was proposed. It can be expressed as follows; based on the pushover curve given by nonlinear static analysis, getting the key parameters when calculating performance point and target point, then substituting them into the structural dynamic formula of elastic SDF system with non - linear fluid viscous dampers, the approprite parameter of the viscous damper can be achieved. Taking a seismic retrofitting example of a three-span continuous girder bridge using FVD, the accuracy and practicality of the parameter determination method given in the paper was validated. The advantages and some problems which should be noticed when using this method were given. The parameter determination method can be used in similar seismic retrofit design of medium and small-span bridges when FVD were

  18. 新白沙沱长江特大桥3号墩双壁钢围堰设计与施工%Design & Construction of Double Wall Steel Cofferdam for Pier No.3 of New Baishatuo Changjiang Super Large Bridge

    Institute of Scientific and Technical Information of China (English)

    郭煜

    2016-01-01

    The pylon foundation of No.3 main tower of Xinbaishatuo Extra Large Bridge across Yan-gtze River was constructed by double-wall steel cased cofferdam.In order to meet the structural safety of double-wall steel cased cofferdam in each stage of construction,modeling calculation and analysis were performed respectively to each construction condition in each stage of construction,such as cof-ferdam assembly,bottom seal,capped slab and tower seat,etc.,so as to ensure safe and reliable structure as well as smooth proceeding of each process.Technique of synchronously constructing bored pile and cofferdam is adopted in construction,the objective of quick construction,safety,good quality and cost saving was reached,the safety of double-wall steel cased cofferdam to tide over flood season was ensured,and solid foundation was laid for the construction time limit objective of the whole bridge.%新白沙沱长江特大桥3号主塔墩基础采用双壁钢套箱围堰施工。为满足双壁钢套箱围堰在施工各阶段的结构安全,分别对围堰拼装、封底、承台及塔座施工等各阶段的施工工况进行建模计算分析,以确保结构安全可靠,各工序顺利进行。施工中采用钻孔桩与围堰同步施工技术,达到了快速施工、安全优质、节约成本的目标,确保了双壁钢套箱围堰的渡洪安全,为全桥的工期目标打下了基础。

  19. Study on the shock absorbing technique of high speed railway bridges

    Institute of Scientific and Technical Information of China (English)

    Li Chenggen; Gao Ri

    2011-01-01

    Based on the idea of "bearing function separation", a structural member called shock absorber that makes use of its plastic deformation is presented for reducing the seismic response of the bridge. The design criterion for matching material stress, strain and earthquake fortification aim, is also given. The analysis results show that the high speed railway box girder with the absorber in this paper has great reduction effect in seismic response of the bridge piers.

  20. Extension of direct displacement-based design methodology for bridges to account for higher mode effects

    OpenAIRE

    Kappos, A. J.; Gkatzogias, K.I.; Gidaris, I.G.

    2013-01-01

    An improvement is suggested to the direct displacement-based design (DDBD) procedure for bridges to account for higher mode effects, the key idea being not only the proper prediction of a target-displacement profile through the effective mode shape (EMS) method (wherein all significant modes are considered), but also the proper definition of the corresponding peak structural response. The proposed methodology is then applied to an actual concrete bridge wherein the different pier heights and ...

  1. Simplified Calculation of "Crack front " of Double Reinforced Concrete Rectangular Piers%双筋矩形截面混凝土墩柱的开裂前沿简化计算

    Institute of Scientific and Technical Information of China (English)

    彭建中; 叶永

    2011-01-01

    According to the theory in basal mechanics, this thesis predigested the mechanical mode of the double reinforced rectangular concrete column, built the mechanical balance equation, and analysed stress process of the pier in theory. Under the condition that regarding concrete is being pulled, we should search the position of neutral axis of the cracking section by "three-phase" theory in order to get function expression of the concrete's resisting power along the length direction of the pier. These calculated results can be applied to the deformation analysis of the reinforced concrete cantilever bridge piers; and " three-phase " theory can be used to calculate stiffness of pier's each section; and the displacement of pier's top; and then be helped to do cracking mechanism of reinforced concrete piers under complex loads.%基于力学理论,对双筋矩形截面混凝土墩柱受力模式进行简化,建立模型的力学平衡方程,并分析墩柱模型的受力过程及开裂机理.运用“三段式”方法,在考虑混凝土受拉的条件下,求解墩柱开裂截面中性轴的位置,得到混凝土抗力△P(z)沿墩身分布的函数表达式.计算结果可适用于钢筋混凝土悬臂桥墩变形分析,提出的“三段式”分析方法可以求出墩柱各截面刚度以及墩柱墩顶位移曲线,有助于钢筋混凝土墩柱在复杂载荷作用下的开裂机理研究.

  2. GFRP seismic strengthening and structural heath monitoring of Portage Creek Bridge concrete columns

    International Nuclear Information System (INIS)

    Located in Victoria British Columbia (BC), Canada, the Portage Creek Bridge is a 124m long, three-span structure with a reinforced concrete piers and abutments on H piles. The bridge was designed prior to the introduction of current bridge seismic design codes and construction practices. Therefore it was not designed to resist the earthquake forces as required by today's standards. The bridge is on a route classified as a Municipal Disaster Route scheduled to be retrofitted to prevent collapse during a design seismic event, with a return period of 475 years (i.e., an event with 105 probability of exceedance in 50 years). Conventional materials and methods were used to retrofit most of the bridge. The dynamic analysis of the bridge predicted the two tall columns of Pier No. 1 will form plastic hinges under an earthquake resulting an additional shear to the short columns of Pier No. 2. A non-liner static pushover analysis indicated the short columns will not be able to form plastic hinges prior to failure in shear. The innovative solution of Fiber Reinforced Polymer wraps (FRPs) was chosen to strengthen the short columns for shear without increasing the moment capacity. The FRP wraps and the bridge were instrumented as one of 36 demonstration projects across Canada sponsored by ISIS (Intelligent Sensing for Innovative Structure) Canada, federally funded Network of Centers of Excellence, to access the performance of FRP and the use of FOS (Fiber Optic Sensors) for Structural Health Monitoring (SHM). The two columns of the bridge pier were strengthened with GFRP (Glass Fiber Reinforced Polymer) wraps with eight bi-directional rosette type strain gauges and four long gauge fiber optic sensors attached to the outer layer of the wraps. In addition, two 3-D Crossbow accelerometers are installed on the pier cap above the columns and a traffic web-cam mounted above the deck at the pier location. The data is collected through high sped internet line to an interactive web page

  3. Statistical Analysis of Ship Collisions with Bridges in China Waterway

    Institute of Scientific and Technical Information of China (English)

    DAI Tong-yu; NIE Wu; LIU Ying-jie; WANG Li-ping

    2002-01-01

    Having carried out investigations on ship collision accidents with bridges in waterway in China, a database of ship collision with bridge (SCB) is developed in this paper. It includes detailed information about more than 200 accidents near ship's waterways in the last four decades, in which ships collided with the bridges. Based on the information a statistical analysis is presented tentatively. The increase in frequency of ship collision with bridges appears, and the accident quantity of the barge system is more than that of single ship. The main reason of all the factors for ship collision with bridge is the human errors, which takes up 70%. The quantity of the accidents happened during flooding period shows over 3~6 times compared with the period from March to June in a year. The probability follows the normal distribution according to statistical analysis. Visibility, span between piers also have an effect on the frequency of the accidents.

  4. 新型耗能辅助墩抗震性能的参数研究%PARAMETRIC STUDIES OF SEISMIC PERFORMANCE ON ENERGY DISSIPATION SUBSIDIARY PIERS

    Institute of Scientific and Technical Information of China (English)

    魏俊; 孙利民

    2012-01-01

    基于地震损伤控制设计的思想,作者提出了一种耗能型辅助墩结构形式.为了研究辅助墩的抗震性能,保护强震作用下超大跨斜拉桥的主塔,该文采用非线性静力分析方法对辅助墩的各种参数进行了分析,探讨了墩柱尺寸及间距,软钢剪力连杆尺寸、布置道数及间距等参数变化对辅助墩抗震性能的影响.结果表明:混凝土墩柱和剪力连杆的刚度需要一个合适的比例,墩柱间距应满足剪力连杆发生剪切型屈服的要求,剪力连杆布置方式的影响可以忽略.%Based on seismic damage control design strategies, a kind of new energy dissipation subsidiary piers is proposed. In order to investigate the seismic performance of subsidiary piers and protect the towers of long span cable-stayed bridges under a strong earthquake, various parameters of subsidiary piers are analyzed employing a nonlinear static analysis method in this paper. The influences of the parameters which include dimensions and spacing of columns, dimensions, numbers and spacing of shear links on the seismic performance of subsidiary piers are discussed. The results show that appropriate stiffness ratio of columns and shear links is needed, and the distance between columns satisfies the requirement of the shear yield of shear links, and the influence of the layout fashion of shear links is ignored.

  5. 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.

  6. 24 CFR 3285.306 - Design procedures for concrete block piers.

    Science.gov (United States)

    2010-04-01

    ... top to the bottom of the pier must not exceed one-half inch. (5) Mortar is not required, unless... not exceeded. Mortar is not required for concrete block piers, unless otherwise specified in the..., in accordance with acceptable engineering practice. Mortar is not required for concrete block...

  7. 77 FR 51475 - Safety Zone; Apache Pier Labor Day Fireworks; Myrtle Beach, SC

    Science.gov (United States)

    2012-08-24

    ... INFORMATION: Table of Acronyms DHS Department of Homeland Security FR Federal Register NPRM Notice of Proposed... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Apache Pier Labor Day Fireworks; Myrtle... establishing a temporary safety zone on the waters of the Atlantic Ocean in the vicinity of Apache Pier...

  8. 77 FR 35862 - Safety Zone; Fleet Week Maritime Festival, Pier 66 Elliott Bay, Seattle, WA

    Science.gov (United States)

    2012-06-15

    ... SECURITY Coast Guard 33 CFR Part 165 Safety Zone; Fleet Week Maritime Festival, Pier 66 Elliott Bay... Guard will enforce the Fleet Week Maritime Festival's Pier 66 Safety Zone in Elliott Bay, WA from 8 a.m... Guard will enforce the Safety Zone for the Fleet Week Maritime Festival in 33 CFR 165.1330 on August...

  9. Piers Harris and Coopersmith Measure of Self-Esteem: A Comparative Analysis

    Science.gov (United States)

    Lynch, Mervin D.; Foley-Peres, Kathleen D.; Sullivan, Stefanie S.

    2008-01-01

    The purposes of this study were to see if the items from the Piers Harris Self Concept Scale and the Coopersmith Self Esteem Inventory had construct and predictive validity. Items used in this study were 50 items from the Coopersmith Self-Esteem Inventory and 80 items from the Piers Harris Self-Concept Scale. Construct measures were obtained using…

  10. 48 CFR 47.303-12 - Ex dock, pier, or warehouse, port of importation.

    Science.gov (United States)

    2010-10-01

    ... warehouse, port of importation. 47.303-12 Section 47.303-12 Federal Acquisition Regulations System FEDERAL..., pier, or warehouse, port of importation. (a) Explanation of delivery term. Ex dock, pier, or warehouse... in the warehouse at the specified port of importation. (b) Contractor responsibilities....

  11. Pier scour monitoring system by bed-level image tracking

    Institute of Scientific and Technical Information of China (English)

    Wen-Yi CHANG; Jihn-Sung LAI; Teng-Yi YU; Franco LIN; Lung-Cheng LEE; Whey-Fone TSAI; Chin-Hsiung LOH

    2014-01-01

    A scour monitoring system with a micro camera tracking the bed-level images is proposed in this study. Two image recognition algorithms have been developed to support the bed-level image tracking approach. Through the laboratory experiments of pier scour, this study demonstrates that the proposed system is able to accurately monitor the scour-depth evolution in real time. In addition, five commonly-used temporal scour models are employed to simulate scour-depth evolution and their results are compared with monitoring data. In general, the results indicate that the proposed scour monitoring system has the potential for further applications in the field.

  12. 76 FR 47441 - Safety Zone; Apache Pier Labor Day Weekend Fireworks Display, Atlantic Ocean, Myrtle Beach, SC

    Science.gov (United States)

    2011-08-05

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Apache Pier Labor Day Weekend Fireworks... vicinity of Apache Pier in Myrtle Beach, South Carolina during a Labor Day weekend fireworks display on... from Apache Pier, which is located on the Atlantic Ocean. The fireworks display is scheduled...

  13. Sea surface temperature variability at the Scripps Institution of Oceanography Pier

    DEFF Research Database (Denmark)

    Checkley, David M.; Lindegren, Martin

    2014-01-01

    similar results. SSTSIO measured over three days shows a diel cycle and short-term variability consistent with rip current transport of warm surf zone water to the end of the SIO pier. We hypothesize that rip current transport increased with the change from the old to the present pier and contributed...... to the observed discontinuity in SIO pier SST. We estimate an artifact of ~ +0.45°C due to both rapid (1988 pier change) and gradual processes. Adjusting the SIO pier SST time series for this artifact reduces the long-term trend from +1.1°C/century to +0.6°C/century, consistent with the global rate of change...

  14. Myocardial Bridging

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2016-02-01

    Full Text Available Abstract Myocardial bridging is rare. Myocardial bridges are most commonly localized in the middle segment of the left anterior descending coronary artery. The anatomic features of the bridges vary significantly. Alterations of the endothelial morphology and the vasoactive agents impact on the progression of atherosclerosis of myocardial bridging. Patients may present with chest pain, myocardial infarction, arrhythmia and even sudden death. Patients who respond poorly to the medical treatment with β-blockers warrant a surgical intervention. Myotomy is a preferred surgical procedure for the symptomatic patients. Coronary stent deployment has been in limited use due to the unsatisfactory long-term results.

  15. Human-simulated intelligent control of train braking response of bridge with MRB

    Science.gov (United States)

    Li, Rui; Zhou, Hongli; Wu, Yueyuan; Wang, Xiaojie

    2016-04-01

    The urgent train braking could bring structural response menace to the bridge under passive control. Based on the analysis of breaking dynamics of a train-bridge vibration system, a magnetorheological elastomeric bearing (MRB) whose mechanical parameters are adjustable is designed, tested and modeled. A finite element method (FEM) is carried out to model and optimize a full scale vibration isolation system for railway bridge based on MRB. According to the model above, we also consider the effect of different braking stop positions on the vibration isolation system and classify the bridge longitudinal vibration characteristics into several cases. Because the train-bridge vibration isolation system has multiple vibration states and strongly coupling with nonlinear characteristics, a human-simulated intelligent control (HSIC) algorithm for isolating the bridge vibration under the impact of train braking is proposed, in which the peak shear force of pier top, the displacement of beam and the acceleration of beam are chosen as control goals. The simulation of longitudinal vibration control system under the condition of train braking is achieved by MATLAB. The results indicate that different braking stop positions significantly affect the vibration isolation system and the structural response is the most drastic when the train stops at the third cross-span. With the proposed HSIC smart isolation system, the displacement of bridge beam and peak shear force of pier top is reduced by 53.8% and 34.4%, respectively. Moreover, the acceleration of bridge beam is effectively controlled within limited range.

  16. A Proposal for 4000m-span Cable-stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Haijun Wang

    2013-06-01

    Full Text Available This study proposed a compound bridge of suspension bridges and cable-stayed bridges with 4000 m super-long-span over the Tsugaru Strait, Japan. Near to the main towers, cable-stayed bridges and prestressed concrete decks are proposed. It is helpful to enhance rigidity and endure the great axial compression force. In the center of the span, suspension bridges and steel box decks are stiffened by trusses, it can reduce self-weigh and the space between girders, thus contribute to aero-elastic stability. RCFT main tower, RC shell pier and RCFT jacket foundation can enhance rigidity and reduce self-weigh. As a result, the live-dead load ratio of proposal is 0.05 and it is equivalent to 2500m-span suspension bridge.

  17. RANDOM ANALYSIS OF HYDRODYNAMIC CHARACTERISTICS OF TRAJECTORY JET CAUSED BY DIFFERENT TYPES OF PIERS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper presents some results on different tail patterns of piers with an overflow dam, and discusses in particular the hydrodynamic characteristics, the distance of water jet scour and the range of erosion area fluctuating for different parameters of average flow field when river beds are under the pressure of water jet scour caused by some special broad-tail piers. The present paper also covers some preliminary research on the relationship of movable bed tests, and introduces the method of calculating the erosion depth and area, therefore provides the best pier pattern in the construction of river beds against erosion.

  18. Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way.......In this paper bridge management systems are discussed with special emphasis on management systems for reinforced concrete bridges. Management systems for prestressed concrete bridges, steel bridges, or composite bridges can be developed in a similar way....

  19. Programmevaluierung Bridge

    OpenAIRE

    Warta, Katharina; Good, Barbara; Geyer, Anton

    2009-01-01

    BRIDGE is an initiative funded by the Ministry for Transport, Innovation and Technology (BMVIT) that aims to close the “funding gap” between basic and applied research in stand-alone projects with the primary objective of jointly developing the potential of basic and applied research. BRIDGE acts as an  umbrella structure under which the Austrian Science Fund (FWF) and the  Austrian Research Promotion Agency (FFG) coordinate two thematically open funding programmes: The ...

  20. National Bridge Inventory (NBI) Bridges

    Data.gov (United States)

    Department of Homeland Security — The NBI is a collection of information (database) describing the more than 600,000 of the Nation's bridges located on public roads, including Interstate Highways,...

  1. Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

    OpenAIRE

    Xiaoguang Deng; Muyu Liu

    2015-01-01

    Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied...

  2. Repair and strengthening of R/C bridges degraded by environmental actions and pollution

    OpenAIRE

    Benedetti, Andrea; Donchev, Ted; Pelà, Luca

    2012-01-01

    Many bridges all around the world experience very hard environmental conditions, and due to the irregular maintenance effort, show different problems of cracking, concrete cover detachment and steel reinforcement wear and corrosion. In general, as a consequence of the polluted rain wetting, the problem is more evident in vertical structures than in the horizontal ones, and serious problems can arise when the piers and columns are very tall. In recent times, the solutions offered by composite ...

  3. Earthquake response analysis of RC bridges using simplified modeling approaches

    Science.gov (United States)

    Lee, Do Hyung; Kim, Dookie; Park, Taehyo

    2009-07-01

    In this paper, simplified modeling approaches describing the hysteretic behavior of reinforced concrete bridge piers are proposed. For this purpose, flexure-axial and shear-axial interaction models are developed and implemented into a nonlinear finite element analysis program. Comparative verifications for reinforced concrete columns prove that the analytical predictions obtained with the new formulations show good correlation with experimental results under various levels of axial forces and section types. In addition, analytical correlation studies for the inelastic earthquake response of reinforced concrete bridge structures are also carried out using the simplified modeling approaches. Relatively good agreement is observed in the results between the current modeling approach and the elaborated fiber models. It is thus encouraging that the present developments and approaches are capable of identifying the contribution of deformation mechanisms correctly. Subsequently, the present developments can be used as a simple yet effective tool for the deformation capacity evaluation of reinforced concrete columns in general and reinforced concrete bridge piers in particular.

  4. Critical traffic loading for the design of prestressed concrete bridge

    International Nuclear Information System (INIS)

    A study has been carried out to determine critical traffic loadings for the design of bridge superstructures. The prestressed concrete girder bridge already constructed in Lahore is selected for the analysis as an example. Standard traffic loadings according to AASHTO (American Association of State Highway and Transportation Officials) and Pakistan Highway Standards are used for this purpose. These include (1) HL-93 Truck, (2) Lane and (3) Tandem Loadings in addition to (4) Military tank loading, (5) Class-A, (6) Class-B and (7) Class-AA loading, (8) NLC (National Logistic Cell) and (9) Volvo truck loadings. Bridge superstructure including transom beam is analyzed Using ASD and LRFD (Load and Resistance Factor Design) provisions of AASHTO specifications. For the analysis, two longer and shorter spans are selected. This includes the analysis of bridge deck; interior and exterior girder; a typical transom beam and a pier. Dead and live loading determination is carried out using both computer aided and manual calculations. Evaluation of traffic loadings is done for all the bridge components to find out the critical loading. HL-93 loading comes out to be the most critical loading and where this loading is not critical in case of bridge decks; a factor of 1.15 is introduced to make it equivalent with HL-93 -Ioading. SAP-2000 (Structural Engineering Services of Pakistan) and MS-Excel is employed for analysis of bridge superstructure subjected to this loading. Internal forces are obtained for the structural elements of the bridge for all traffic loadings mentioned. It is concluded that HL-93 loading can be used for the design of prestressed concrete girder bridge. Bridge design authorities like NHA (National Highway Authority) and different cities development authorities are using different standard traffic loadings. A number of suggestions are made from the results of the research work related to traffic loadings and method of design. These recommendations may be

  5. 变截面高墩翻模施工技术%On high pier turnover construction technique of variable cross-section

    Institute of Scientific and Technical Information of China (English)

    李飞前

    2014-01-01

    以新建云桂铁路某大桥施工实践为例,介绍了变截面高墩翻模施工的原理,分析了模板的设计方案及翻模施工方案,并对四面变截面高墩施工技术进行了介绍,为今后同类工程施工提供有益借鉴。%Taking the construction practice of some bridge along newly-built Nanning-Kunming Railway as the example,the paper introduces the principle for the high pier turnover construction technique of variable cross-section,analyzes the design scheme for the model and the turnover construction scheme,and introduces the four-sided high pier turnover construction technique of variable cross-section,so as to provide some ref-erence for similar engineering construction in future.

  6. 上跨营业线异形墩的设计构想与实施%Design conception and implementation of cross business line shaped pier

    Institute of Scientific and Technical Information of China (English)

    王德明

    2016-01-01

    本文通过在跨越既有营业线位置新建高铁异形桥墩的工程实例,简要介绍上跨营业线异形转体墩的设计构想及施工注意事项,大大降低新建桥墩对营业线的干扰,且减少征地拆迁投入,有着明显的效果,为类似工程情况处理提供借鉴。%In this paper,the across both the business line location of new high iron shaped pier engineering example,briefly introduces the cross business line shaped swivel pier design and construction matters needing attention, greatly reduce the interference of the newly built bridge on the line of business and reduce investment in land acquisition and demolition, has a significant effect,for similar engineering and provide reference.

  7. 变截面高墩翻模施工技术%On high pier turnover construction technique of variable cross-section

    Institute of Scientific and Technical Information of China (English)

    李飞前

    2014-01-01

    Taking the construction practice of some bridge along newly-built Nanning-Kunming Railway as the example,the paper introduces the principle for the high pier turnover construction technique of variable cross-section,analyzes the design scheme for the model and the turnover construction scheme,and introduces the four-sided high pier turnover construction technique of variable cross-section,so as to provide some ref-erence for similar engineering construction in future.%以新建云桂铁路某大桥施工实践为例,介绍了变截面高墩翻模施工的原理,分析了模板的设计方案及翻模施工方案,并对四面变截面高墩施工技术进行了介绍,为今后同类工程施工提供有益借鉴。

  8. Evaluation of streambed scour at bridges over tidal waterways in Alaska

    Science.gov (United States)

    Conaway, Jeffrey S.; Schauer, Paul V.

    2012-01-01

    Engineering Center’s River Analysis System model, and scour depths were calculated using methods recommended by the Federal Highway Administration. Computed contraction-scour depths were greater than 2.0 feet at five bridges and computed pier-scour depths were 4.0 feet or greater at 15 bridges. The potential for streambed scour by both coastal and riverine processes at the bridges considered in this study were evaluated, ranked, and summed to determine a cumulative risk factor for each bridge. Possible factors that could mitigate the scour risks were investigated at 22 bridges that had high individual or cumulative rankings. Mitigating factors such as piers founded in bedrock, deep pier foundations relative to scour depths, and lack of observed scour during field measurements were documented for 13 sites, but additional study and monitoring is needed to better quantify the streambed scour potential for nine sites. Three bridges prone to being affected by storm surges will require more data collection and possibly complex hydrodynamic modeling to accurately quantify the streambed scour potential. Continuous monitoring of water-surface and streambed elevation at one or more piers is needed for two bridges to better understand the tidal and riverine influences on streambed scour.

  9. Analysis on Seismic Effect of Pile-soil Action against CFST and Concrete Composite Column Pier%钢管混凝土叠合柱式桥墩考虑桩土作用的地震效应分析

    Institute of Scientific and Technical Information of China (English)

    曾彦; 曾勇; 赵顺波

    2012-01-01

    为减小桥墩阻水面积,南水北调中线工程跨主干渠大油村北桥中墩墩身采用圆形钢管混凝土叠合柱,以避开阻水超限的普通钢筋混凝土桩柱式结构。探讨考虑桩土相互作用的三种模型并对计算结果进行了对比分析。发现等效三弹簧模型能较好地模拟桩土相互作用下桩基的地震反应,同时说明叠合柱能以较小的直径满足既定承载能力的要求,比普通钢筋混凝土桩柱式结构具有更好的经济性和抗震性能。%In order to reduce the water resistance area of bridge pier, the intermediate pier of the Dayoucun North Bridge crossing the trunk cannel of the Central Line of the South-to-North Water Diversion Project was designed as a circular concrete-filled steel tube (CFST) and concrete composite column pier. Three models considering the interaction between pile and soil are discussed and the calculating results are compared and analyzed. Then it is found that the equivalent spring model can simulate the seismic response of the pile foundation under pile-soil interaction better; while it is showed that the composite pier can meet the existing load bearing capacity requirement just with small diameter and has better economy and seismic resistance performance than those of the common concrete pile column pier.

  10. 北京某矮塔斜拉桥的设计与施工实践%Study on Design and Construction of one Extradosed Cable-Stayed Bridge in Beijing

    Institute of Scientific and Technical Information of China (English)

    庄年; 应伟强

    2011-01-01

    The main bridge of Tongzhou Yudaihe Bridge is a kind of prestressed concrete extradosed cable-stayed bridge with four span three pylon and double-cable-plane. Spans are attributed as (45 + 85 + 85 +45) m. The middle tower girder and pier are fixed. The side tower girder and pier are separated and supports mounted on the top of pier. Taking this bridge as an example, the characteristics of bridge type and force principle of the extradosed cablestayed bridge are simply analyzed. In this paper, the design conception and design gist of this type bridge are mainly introduced, and the construction scheme and construction techniques of this bridge are discussed.%北京通州玉带河大桥主桥为4跨3塔双索面预应力混凝土矮塔斜拉桥,主桥孔跨为45+85+85+45m,采用中塔塔梁固结、边塔塔梁与墩分离、墩顶设支座的结构形式.本文以该桥为例,浅析了预应力混凝土部分斜拉桥的桥型特点、受力特性,主要介绍了该类桥型的设计构思及要点,论述了该桥施工方案的选择及施工要点.

  11. Species composition and catch per unit of effort of Monterey Bay surf, pier, and skiff anglers in 1979

    OpenAIRE

    Spratt, Jerome D.

    1982-01-01

    In 1979, Monterey Bay sport anglers were sampled for species composition of the catch and catch per unit of effort. A total of 4150 surf, pier, and skiff anglers was interviewed. Catch per hour was 0.71, 0.58, and 1.25 for surf, pier, and skiff anglers, respectively. Barred surfperch, Amphisticus argenteus, totaled 76% of the surf catch. The species composition of the pier catch was dominated by juvenile bocaccio, Sebastes paucispinis; white croaker, Genyonemus lineatus; and walleye sur...

  12. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...... in the Media”, “Audience Interactivity and Participation”, “The Role of Media and ICT Use for Evolving Social Relationships” and “Audience Transformations and Social Integration”. Building Bridges is the result of an ongoing dialogue between the Action and non-academic stakeholders in the field of audience...

  13. Building Bridges

    DEFF Research Database (Denmark)

    The report Building Bridges adresses the questions why, how and for whom academic audience research has public value, from the different points of view of the four working groups in the COST Action IS0906 Transforming Audiences, Transforming Societies – “New Media Genres, Media Literacy and Trust...

  14. Vorticity and Circulation of Horseshoe Vortex in Equilibrium Scour Holes at Different Piers

    Science.gov (United States)

    Das, S.; Das, R.; Mazumdar, A.

    2014-06-01

    The present work deals with an experimental investigation on clear water local scour and horseshoe vortex flow field of cohesionless bed sediment around an equilateral triangular pier (side facing the approaching flow). The turbulence field within the equilibrium scour hole is experimentally measured in a laboratory tilting flume using an Acoustic Doppler Velocimeter. The experiment is conducted for the approaching flow having undisturbed flow depth (=0.125 m) greater than the pier width and the depth-averaged approaching flow velocity (=0.247 m/s) about 68 % of the critical velocity of the uniform bed sand of median diameter of 0.825 m. The triangular pier width is 0.11 m. The outcomes of triangular pier have been compared with the square pier (side facing the approaching flow) and circular pier obtained from previous study. The distribution of time-averaged velocity vectors, contours of the vorticities and turbulent kinetic energies at different azimuthal planes (0° i.e. at the upstream axis of symmetry, 45° and 90°) are presented. Vector plots of the flow field at azimuthal planes reveal the characteristics of the horseshoe vortex flow. The circulation of the horseshoe vortex is determined by using Stokes theorem and forward difference technique. An attempt has also been made to correlate the horseshoe vortex strength with the effective obstruction width of pier for equilibrium scour hole at different azimuthal angles. The presented data would be useful for the development and validation of turbulence field models that can be used to find out the strength of the horseshoe vortex.

  15. Finite Element and Experimental Analysis and Evaluation of Static and Dynamic Responses of Oblique Pre-stressed Concrete Box Girder Bridge

    Directory of Open Access Journals (Sweden)

    Ali Fadhil Naser

    2013-10-01

    Full Text Available Hashuang bridge is type of prestressed concrete box girder oblique bridge and it is located in Harbin City within Heilongjiang province in the east north of China. The objectives of this study are to investigate the appearance of the bridge structure and identify all the damages in the bridge structural members and to evaluate the structural performance of the bridge structure under dead and live loads. Finite element analysis is used to analyze the static designed internal forces and dynamic responses by adopting SAP200 software Ver. 14.2.0. Static and dynamic load test are adopted to evaluate the structural performance of the bridge structure. The results of field investigation process of the bridge appearance show that the bridge suffers from serious damages. The web of box girder of the second span near pier No.2 (in the quarter of middle span at 39m on the bridge length suffers from serious shear cracks. The state of abutments, piers and sidewalks is good, but the bearing, drainage holes, steel rail and expansion joints are not good and they suffer from much damage. The steel rail is corroded and the expansion joint loses the material which fills the joint. There are many dusts and debris is collected on the bridge deck in the location near sidewalk. The analysis results of finite element and load tests show that there are high tensile stresses in the quarter of middle span at distance 39 m of the bridge length and the state of the bridge structure is not good and the main problem of the bridge structure in the original design of prestressed tendons. Therefore, this study recommends for repairing and strengthening the bridge structure to increase the stiffness and strength and to improve the bearing capacity of the bridge structural members to increase the service live of the bridge structure.

  16. Bridged graphite oxide materials

    Science.gov (United States)

    Herrera-Alonso, Margarita (Inventor); McAllister, Michael J. (Inventor); Aksay, Ilhan A. (Inventor); Prud'homme, Robert K. (Inventor)

    2010-01-01

    Bridged graphite oxide material comprising graphite sheets bridged by at least one diamine bridging group. The bridged graphite oxide material may be incorporated in polymer composites or used in adsorption media.

  17. On maintenance strategies of roads and bridges%谈公路桥梁养护对策

    Institute of Scientific and Technical Information of China (English)

    赵文峰

    2015-01-01

    The paper analyzes the meaning and aims of the road and bridge maintenance,illustrates factual maintenance measures of bridges and roads from the bridge beam maintenance,bridge pier maintenance,and deck maintenance,so as to prolong the life of roads and bridges and re-duce the times and cost of the roads and bridge maintenance by the maintenance measures.%分析了公路桥梁养护的意义及目的,从桥梁梁板养护、桥梁墩台养护、桥面铺装养护三方面,阐述了公路桥梁的具体养护措施,以延长公路桥梁的使用年限,减少公路桥梁修复的次数与成本。

  18. Mechanics model of additional longitudinal force transmission between bridges and continuously welded rails with small resistance fasteners

    Institute of Scientific and Technical Information of China (English)

    徐庆元; 周小林; 曾志平; 杨小礼

    2004-01-01

    A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement among the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges.

  19. Construction Technique for River Pier Foundations Sitting on Bare Rock Riverbed%裸岩河床水中墩基础施工技术

    Institute of Scientific and Technical Information of China (English)

    申永利

    2016-01-01

    长昆客专罗旧舞水特大桥主桥为(48+2×80+48) m连续梁桥,1号~3号桥墩位于主河槽内,低桩承台嵌入河床裸岩中,设16根φ1.5 m钻孔桩。根据裸岩河床、低桩承台的特点,确定水中墩基础施工采用施工栈桥为交通便道、施工平台,栈桥标准跨度18 m ,设4组贝雷梁、双排钢管桩基础,并在钢管桩周围抛填砂砾、投放石笼或下放钢套箱、灌注水下混凝土以及拉设缆风绳。水中墩基础采用矩形双壁钢围堰围护方案,按照“先堰后桩”顺序施工。水中墩基础施工中,采用长臂挖机清底,利用岩石乳化炸药和非电微差雷管进行水下岩石爆破;钢护筒采用振动锤夹持、插打;双壁钢围堰依靠钻孔桩护筒、平台辅助钢管桩逐块拼装,用倒链下放、汽车吊接高下沉施工;围堰封底混凝土等强后,进行钻孔桩、承台和墩柱施工,最后拆除围堰。%The main bridge of Luojiu Wushui River Bridge on the Changsha‐Kunming Passen‐ger Dedicated Railway is a (48+2 × 80+48) m continuous beam bridge .The pier No .1 ,pier No .2 and pier No .3 stand in the main river channel ,the low pile caps of w hich are embedded in the bare rocks on the riverbed .T he foundation of the pier consists of 16 bored piles each 1 .5 m in diameter . To suit the characteristics of the bare rock riverbed and the low pile caps ,the construction trestle was used as the transportation access and the construction platform during the construction of the river pier foundations .The trestle ,with standard span length of 18 m ,consists of 4 groups of bai‐ley beams that are supported by two rows of steel pipe piles .The steel pipe piles were surrounded by riprap ,based on which the stone cage or suspended steel box was lowered .Then the tremie concrete was cast and wind cables were installed and tensioned .The river pier foundation was con‐structed with the assistance of the rectangular

  20. HYDRAULIC CHARACTERISTICS OF BOTTOM UNDERLAY-TYPE PIER FOR WATER-WING CONTROL

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The pier, placed at the outlet of the pressure flow section, is an effective design to deal with the problems of the manufacture and operation of the gates for a discharge tunnel with high water head. It is crucial to control the water-wing, induced by this type of the pier. Through observing the phenomena of the water-wing, the reason of the water-wing inception, i.e., the concave of the flow surface, was presented, and a type of the new pier with bottom underlay was designed. The hydraulic characteristics of the pier, including the variations of the water-wing features, both length and height, with the water head, as well as with the concave depth, and with the height of the bottom underlay, and the variations of the concave depth with the height of the bottom underlay, were investigated by physical model experiments. The results show that the approach of the modification of the concave through the structures with the bottom underlay-type pier is remarkably effective in the water-wing control.

  1. Streambed scour evaluations and conditions at selected bridge sites in Alaska, 2012

    Science.gov (United States)

    Beebee, Robin A.; Schauer, Paul V.

    2015-11-19

    Streambed scour potential was evaluated at 18 river- and stream-spanning bridges in Alaska that have unknown foundation details or a lack of existing scour analysis. All sites were evaluated for stream stability and long-term scour potential. Contraction scour and abutment scour were calculated for 17 bridges, and pier scour was calculated for 7 bridges that had piers. Vertical contraction (pressure flow) scour was calculated for sites with overtopping floods (where the modeled water surface was higher than the superstructure of the bridge). In most cases, hydraulic models of the 1- and 0.2-percent annual exceedance probability floods (also known as the 100- and 500-year floods, respectively) were used to derive hydraulic variables for the scour calculations. Alternate flood values were used in scour calculations for sites where smaller floods overtopped a bridge or where standard flood-frequency estimation techniques did not apply. Scour was also calculated for large recorded floods at several sites. Equations for scour in cohesive soils were used for sites where streambed sediment was silt-sized or smaller.

  2. Evaluation of the earthquake resistant capacity of three-dimensional multi-span rigid frame bridges; Takeikan rittai ramen kyoryo no taishinsei hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Shimamura, K.; Kasabo, H.; Ando, K.; Tanaka, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-07-01

    The earthquake resistant capacity was evaluated for three-dimensional multi-span rigid frame bridges based on the seismic response analysis results using a finite element method model. For the analyzed bridge model, three-span curved bridge and four-span straight bridge is jointed by the beam border. There are wide-span steel rigid frame piers with underground beams and racket-type piers. Specified seismic acceleration such as occurred at the Hyogo-ken Nanbu Earthquake was used for the analysis condition. According to the analysis model, analysis condition and analysis procedure, analysis results are illustrated for the eigen vibration analysis, effects of time span on the time history response analysis, effects of propagation velocity of seismic waves, elasto-plastic time history response analysis, and static cyclic response analysis. Then, the evaluation results of earthquake resistant capacity are provided for the examinations of stiffener properties, generated strain, plasticity rate, strength of anchors, safety factor against the breakdown, residual displacement of the border model of two sections of girder of piers, and evaluation of the earthquake resistant capacity of the entire bridge. 4 refs., 25 figs., 5 tabs.

  3. 78 FR 20623 - Environmental Impact Statement for Modernization and Repair of Piers 2 and 3, Military Ocean...

    Science.gov (United States)

    2013-04-05

    ... and 3 are used to transport military supplies in the Pacific region. There may be significant impacts... Department of the Army Environmental Impact Statement for Modernization and Repair of Piers 2 and 3, Military...-needed modernization and repairs of Piers 2 and 3, Military Ocean Terminal Concord (MOTCO) due...

  4. Remediation of Centre Pier, Port Hope, Ontario: Historical, Logistical, Regulatory and Technical Challenges - 13118

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson Jones, Andrea [MMM Group Limited, 100 Commerce Valley Drive West, Thornhill, Ontario, L3T 0A1 (Canada); Case, Glenn [Atomic Energy of Canada Limited, 115 Toronto Road, Port Hope, Ontario, L1A 3S4 (Canada); Lawrence, Dave [Public Works and Government Services Canada, 115 Toronto Road, Port Hope, Ontario, L1A 3S4 (Canada)

    2013-07-01

    Centre Pier is a 3.9 ha property owned by the Commissioners of the Port Hope Harbour in the Municipality of Port Hope, Ontario, Canada. It is centrally located on the Port Hope waterfront and is bounded on the west by the Port Hope Harbour, on the east by the Ganaraska River, on the south by Lake Ontario, and on the north by a railway corridor. The property is currently leased by the Commissioners of the Port Hope Harbour to the Cameco Corporation which owns the four onsite building that are used as warehouse space for their uranium conversion facility located on the western side of the Harbour. Remediation of this site forms part of the Port Hope Project being undertaken by Atomic Energy of Canada Limited (AECL) and Public Works and Government Services Canada (PWGSC) as part of the Port Hope Area Initiative (PHAI). Soil impacts include radiological, metals and petroleum hydrocarbons resulting from long term historical industrial use. Radiological impacts in soil extend across most of the site primarily within the upper metre of fill. Metals-contaminated soil is present across the entire site in the underlying fill material. The metals-contaminated fill extends to a maximum depth of 2.0 m below grade at the north end of the site which is underlain by peat. However, the metals-contaminated soil could extend to the top of the bedrock on the remainder of the site. Based on the elevation of the bedrock in the adjacent river and Harbour Basin, the metals-contaminated soil may extend to a depth of 5.6 m or 6.5 m below existing grade. Petroleum-contaminated soil is present on the southeast side of the site, where a storage tank farm was previously located. Challenges include: - The complex history of the site both relating to site use and Pier construction. Pier development began in the 1800's and was undertaken by many different entities. Modifications and repairs were made over the years resulting in several different types of Pier walls and fill that must be

  5. Numerical Analysis of Interaction Between Pile-Supported Pier and Bank Slope

    Institute of Scientific and Technical Information of China (English)

    王年香

    2001-01-01

    Two- and three-dimensional finite element analysis programs for pile-soil interaction are compiled. Duncan-Chang's Model is used. The construction sequence of the pier is modeled. The pile-soil interface element is used. The influence of the combination type of piles on the deformation of bank slope and pile behaviour is analyzed. Different designs of a pile-supported pier are compared thoroughly. Calculation results show that the stresses and displacements of the pile are directly related to the distance from the bank slope and the direction of inclination. An inclined prop pile set in the rear platform would remarkably reduce the stresses of piles and the displacement of the pier.

  6. 城市桥梁被车辆撞击后损伤分析%Analysis on Damage of Urban Bridges Caused by Vehicle Collision

    Institute of Scientific and Technical Information of China (English)

    裴小吟; 文传勇; 张永水

    2011-01-01

    The stress state of the bridge pier under the collision of heavy vehicles with different speeds, and the collision mechanism of vehicle and bridge are mainly studied. The simulation analysis of piers and vehicles is carried out on the basis of the general finite element program ABAQUS. The plain concrete three-dimensional entity model is used as the pier model. The nonlinearity of concrete material is fully considered and reinforced steel is calculated with the consideration of liner elasticity. Ordinary steel entity model is used as the vehicle model, without the consideration of the impact on the vehicles in the collision. Simulated analyses which aim at the situation of vertical impact on the pier caused by different vehicles with three different speeds are carried out. Analyses show that the stress of the pier's collision point is firstly increased with the increase of time, and then the stress will decrease when it reaches the maximum value. This characteristic conforms to the plastic destruction law of the concrete. Meanwhile, analyses also show that the higher the vehicle speed is, the larger the stress and displacement of the pier reaches.%通过研究城市桥梁中当桥墩在重型车辆撞击下的受力状态及车-桥的碰撞机理,采用有限元软件ABAQUS对3种不同车速车辆垂商撞击桥墩的情况进行了模拟分析.分析表明:桥墩被撞击位置处的应力先随时间的增加而增大,达到最大值时,既又随之减小,符合混凝土的弹塑性破坏;并且车速越大,桥墩局部达到的应力及位移也越大.

  7. Behavior of composite rigid frame bridge under bi-directional seismic excitations

    Directory of Open Access Journals (Sweden)

    Xiaogang Liu

    2014-02-01

    Full Text Available Pushover analysis and time history analysis are conducted to explore the bi-directional seismic behavior of composite steel-concrete rigid frame bridge, which is composed of RC piers and steel-concrete composite girders. Both longitudinal and transverse directions excitations are investigated using OpenSees. Firstly, the applicability of pushover analysis based on the fundamental mode is discussed. Secondly, an improved pushover analysis method considering the contribution of higher modes is proposed, and the applicability on composite rigid frame bridges under bi-directional earthquake is verified. Based on this method, an approach to predict the displacement responses of composite rigid frame bridge under random bi-directional seismic excitations by revising the elasto-plastic demand curve is also proposed. It is observed that the developed method yield a good estimate on the responses of composite rigid frame bridges under bi-directional seismic excitations.

  8. Non-rigid connector in fixed partial dentures with pier abutment: An enigma simplified

    Directory of Open Access Journals (Sweden)

    Prince Kumar

    2012-01-01

    Full Text Available In the fixed partial denture (FPD prosthesis with rigid connectors, forces of mastication are transmitted to the terminal retainers, which make the middle abutment act as a class I lever fulcrum. This techno-clinical cycle often causes failure of the fixed partial dentures. To overcome this dilemma, a non-rigid connector may be incorporated on the distal aspect of the middle (pier abutment. The non-rigid connector counterbalances the effects of these forces of leverage. This clinical report presents the use of a non-rigid connector in a long-span, five-unit FPD, replacing two missing teeth with an intermediate pier abutment.

  9. Discussion on the Construction Technology of Variable Cross-section Hollow Thin-walled Pier%浅谈变截面空心薄壁方墩施工技术

    Institute of Scientific and Technical Information of China (English)

    陈显福

    2014-01-01

    Variable cross-section hol ow thin-walled pier has the obvious superiority and good economy, and can use less material to obtain larger sectional resistance moment which is often used by mountain bridge engineering. Taking the Yujiagou1# bridge as the example, this article introduces the construction technology of variable cross-section hol ow thin-wal ed pier, and provides reference for similar engineering construction.%变截面空心薄壁方墩具有明显的优越性和较好的经济性,可以用较少的材料获取较大的截面抵抗矩,这种技术常常被山区、深沟建桥的工程所采用。本文以余家沟1号大桥为例,介绍了变截面空心薄壁方墩施工技术,可为类似工程施工提供借鉴。

  10. Random Vibration Analysis of Train Moving over Slab Track on Bridge under Track Irregularities and Earthquakes by Pseudoexcitation Method

    Directory of Open Access Journals (Sweden)

    Zhiping Zeng

    2015-01-01

    Full Text Available This paper investigates the random vibration and the dynamic reliability of operation stability of train moving over slab track on bridge under track irregularities and earthquakes by the pseudoexcitation method (PEM. Each vehicle is modeled by multibody dynamics. The track and bridge is simulated by a rail-slab-girder-pier interaction finite element model. The coupling equations of motion are established based on the wheel-rail interaction relationship. The random excitations of the track irregularities and seismic accelerations are transformed into a series of deterministic pseudoexcitations by PEM. The time-dependent power spectral densities (PSDs of the random vibration of the system are obtained by step-by-step integration method, and the corresponding dynamic reliability is estimated based on the first-passage failure criterion. A case study is then presented in which a high-speed train moves over a slab track resting on a simply supported girder bridge. The PSD characteristics of the random vibration of the bridge and train are analyzed, the influence of the wheel-rail-bridge interaction models on the random vibration of the bridge and train is discussed, and furthermore the influence of train speed, earthquake intensity, and pier height on the dynamic reliability of train operation stability is studied.

  11. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    Science.gov (United States)

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

  12. Dynamic Response Analysis of High-speed Railway Bridge under Rare Earthquake Action%罕遇地震作用下高速铁路桥墩动力响应分析

    Institute of Scientific and Technical Information of China (English)

    季小勇

    2012-01-01

    The finite element model of high-speed railway bridge pier is established, which is involved in the multi-span simply supported bridge. By means of finite element software and bending moment-curvature relationship program, the elastoplastic dynamic analysis of high-speed bridge pier is presented, the earthquake responses of bridge pier are calculated under different earthquake action combination and train loading with different speed. Calculation results show that the dynamic responses will increase with increment of speed of vehicles, the displacements of the structure will increase significantly, the bridge pier bottom step into the state of elastic-plasticity, the plastic hinge will be developed at the bottom of piers under rare earthquake action, and therefore, the numerical results of plastic hinge length are verified compared with AASHTO code.%建立了列车荷载作用下高速铁路桥墩模型,将桥墩纳入高速铁路简支梁桥全桥体系中进行动力分析.采用弯矩-曲率关系计算程序以及有限元软件,对高速铁路桥墩进行弹塑性分析计算,分别计算了罕遇地震作用下不同车速和不同地震作用组合等工况下的桥梁的弹塑性地震响应.计算结果表明,随着车速的增加,桥梁的地震响应呈上升趋势,结构位移较大;罕遇地震作用下高铁桥梁墩底进入弹塑性状态,给出塑性铰长度数值计算结果,并与AASHTO规范对比验证.

  13. Design of bridges against large tectonic deformation

    Institute of Scientific and Technical Information of China (English)

    I.Anastasopoulost; G.Gazetas; V.Drosos; T.Georgarakos; R.Kourkoulis

    2008-01-01

    The engineering community has devoted much effort to understanding the response of soil-structure systems to seismic ground motions,but little attention to the effects of an outcropping fault offset.The 1999 earthquakes of Turkey and Taiwan,offering a variety of case histories of structural damage due to faulting,have (re)fueled the interest on the subject.This paper presents a methodology for design of bridges against tectonic deformation.The problem is decoupled in two analysis steps:the first (at the local level) deals with the response of a single pier and its foundation to fault rupture propagating through the soil,and the superstructure is modeled in a simplified manner;and the second (at the global level)investigates detailed models of the superstructure subjected to the support (differential) displacements of Step 1.A parametric study investigates typical models of viaduct and overpass bridges,founded on piles or caissons.Fixed-head piled foundations are shown to be rather vulnerable to faulting-induced deformation.End-bearing piles in particular are unable to survive bedrock offsets exceeding 10 cm.Floating piles perform better,and if combined with hinged pile-to-cap connections,they could survive much larger offsets.Soil resilience is beneficial in reducing pile distress.Caisson foundations are almost invariably successful.Statically-indeterminate superstructures are quite vulnerable,while statically-determinate are insensitive (allowing differential displacements and rotations without suffering any distress).For large-span cantilever construction bridges,where a statically determinate system is hardly an option,inserting resilient seismic isolation bearings is advantageous as long as ample seating can prevent the deck from falling off the supports.An actual application of the developed method is presented for a major bridge,demonstrating the feasibility of design against tectonic deformation.

  14. Liberalism is Always Greener on the Other Side of Mill: A Reply to Piers Stephens

    NARCIS (Netherlands)

    Wissenburg, M.L.J.

    2001-01-01

    Given our shared interest in giving green political thought a basis in liberalism, I discuss five of Piers Stephens' objections to Green Liberalism. (1) I deny that I use preferences as black boxes, prejudicing liberalism in favour of a human-nature divide. (2) I argue that my characterisation of li

  15. 75 FR 8563 - Safety Zone; Fleet Week Maritime Festival, Pier 66, Elliott Bay, Seattle, WA

    Science.gov (United States)

    2010-02-25

    ... public dockets in the January 17, 2008, issue of the Federal Register (73 FR 3316). Public Meeting We do... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Fleet Week Maritime Festival, Pier 66... aerial spectator events associated with the annual Fleet Week Maritime Festival. Entry into,...

  16. 33 CFR 165.1121 - Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security Zone: Fleet Supply... Guard District § 165.1121 Security Zone: Fleet Supply Center Industrial Pier, San Diego, CA. (a... feet from the north, west, and south sides of the Fleet Industrial Supply Center enclosed by...

  17. 76 FR 30014 - Safety Zone; Fleet Week Maritime Festival, Pier 66, Elliott Bay, Seattle, WA

    Science.gov (United States)

    2011-05-24

    ..., Seattle, WA'' in the Federal Register (75 FR 037). We received 72 comments on the proposed rule. We made... rulemaking (SNPRM) with the same title in the Federal Register (75 FR 226). We received 110 comments on the... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; Fleet Week Maritime Festival, Pier...

  18. EXPERIMENTAL STUDY ON CAVITATION AND WATER-WING FOR MIDDLE-PIERS OF DISCHARGE TUNNELS

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; CAI Chang-guang; JI Wei; RUAN Shi-ping; LUO Chao

    2005-01-01

    In construction of high dams, design of a middle-pier, placed in a discharge tunnel to divide it into two parts, is a better choice that could breakthrough the limits of the manufacture and operation of the gate due to the high head to it. However, cavitation and water-wing, a kind of flow striking the top and side walls of the tunnel, induced by the middle-pier, may take place and bring about bad effects on operation of the tunnel. The experiments of the six comparing plans were conducted, consisting of atmospheric and vacuum tank models, and the interesting areas included relationships between discharges and reservoir levels, measurements of side wall pressures, comparisons of water-wing states for the various middle-piers, estimations of the incipient cavitation numbers and the flow cavitation numbers, and analyses of cavitation characteristics for the tunnel. A kind of new bodily form of middle-pier was developed. Water-wing states were better improved and non-cavitation conditions were satisfied.

  19. Design of Danyang Road Bridge in Heze City%菏泽市丹阳路大桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟

    2015-01-01

    菏泽市丹阳路大桥为(40+100+240+100+40) m 双塔中央单索面半飘浮体系混凝土斜拉桥。该桥塔、墩固结,主梁与塔、墩间设置横、竖向支座和纵向液压阻尼器;主梁采用单箱三室斜腹板截面,高3.6m。桥塔采用顺桥向人字形的独柱混凝土塔,高68.2m,单箱单室矩形空心截面。人字形塔柱穿过主梁,与墩身顺接,墩身采用十字形空心薄壁截面,矩形承台,布置33根φ2.0m钻孔灌注桩。辅助墩和交接墩均采用花瓶形双柱式框架墩,矩形承台,布置8根φ1.5m钻孔灌注桩。斜拉索采用φ7 mm镀锌高强平行钢丝束。采用MIDAS Civil 2006和SCDS平面程序对该桥进行计算分析,结果表明该桥各项检算均满足规范要求。%T he Danyang Road Bridge in Heze City is a semi‐floating system concrete cable‐stayed bridge with double pylons ,a central single cable plane and with span arrangement (40+100+240+100+40) m .T he pylons and piers of the bridge are rigidly fixed and in betw een the main girder and pylons and piers ,the lateral and vertical bearings and the longitudinal hydraulic damp‐ers are arranged .The cross section of the main girder is the section of triple‐cell single box with in‐clined webs and the girder is 3 .6 m in depth .In the longitudinal direction of the bridge ,a pylon is the single‐column concrete pylon in the shape of inverted Y ,is 68 .2 m in height and the cross sec‐tion of the pylon is the rectangular hollow section of single‐cell single box .The inverted Y‐shape pylon passes through the main girder and is smoothly fixed with the pylon pier .The cross section of the pylon pier is the crisscross hollow thin‐wall section and the pier stands on the rectangular pile cap under w hich 33 nos .of φ2 .0 m bored piles are arranged .T he auxiliary piers and boundary piers are all the vase‐shape double‐column frame piers and respectively stand on each rectangular

  20. Comparison of Characteristics of Horseshoe Vortex at Circular and Square Piers

    Directory of Open Access Journals (Sweden)

    Subhasish Das

    2013-05-01

    Full Text Available This study presents an experimental investigation on the characteristics of horseshoe vortex system within the equilibrium scour hole at circular and square pier measured by an Acoustic Doppler Velocimeter (ADV. Two tests were conducted for the approaching flow having undisturbed flow depth (= 0.125 m greater than the pier width and the depth-averaged approaching flow velocity (= 0.247 m/s about 68% of the critical velocity of the uniform bed sand that had a median diameter of 0.825 m. The flow measurements by the ADV were taken within the equilibrium scour hole at a circular pier of width 0.11 m. In order to have a comparative study, the ADV measurements within an equilibrium scour hole at a square pier (side facing the approaching flow of sides equaling the width of the circular pier were also taken. The contours and distributions of the time-averaged velocities, turbulence intensities, turbulent kinetic energy and Reynolds stresses at different azimuthal planes (0° i.e., at the upstream axis of symmetry, 45° and 90° are presented. Velocity vector plots of the flow field at azimuthal planes are used to show further flow features. The circulation of the horseshoe vortex is determined by using Stokes theorem and Forward difference technique. Bed-shear stresses are also determined from the Reynolds stress distributions. The flow characteristics of the horseshoe vortex are discussed from the point of view of the similarity with the velocity and turbulence characteristic scales.

  1. High Performance Building Facade Solutions - PIER Final Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eleanor; Selkowitz, Stephen

    2009-12-31

    Building facades directly influence heating and cooling loads and indirectly influence lighting loads when daylighting is considered, and are therefore a major determinant of annual energy use and peak electric demand. Facades also significantly influence occupant comfort and satisfaction, making the design optimization challenge more complex than many other building systems.This work focused on addressing significant near-term opportunities to reduce energy use in California commercial building stock by a) targeting voluntary, design-based opportunities derived from the use of better design guidelines and tools, and b) developing and deploying more efficient glazings, shading systems, daylighting systems, facade systems and integrated controls. This two-year project, supported by the California Energy Commission PIER program and the US Department of Energy, initiated a collaborative effort between The Lawrence Berkeley National Laboratory (LBNL) and major stakeholders in the facades industry to develop, evaluate, and accelerate market deployment of emerging, high-performance, integrated facade solutions. The LBNL Windows Testbed Facility acted as the primary catalyst and mediator on both sides of the building industry supply-user business transaction by a) aiding component suppliers to create and optimize cost effective, integrated systems that work, and b) demonstrating and verifying to the owner, designer, and specifier community that these integrated systems reliably deliver required energy performance. An industry consortium was initiated amongst approximately seventy disparate stakeholders, who unlike the HVAC or lighting industry, has no single representative, multi-disciplinary body or organized means of communicating and collaborating. The consortium provided guidance on the project and more importantly, began to mutually work out and agree on the goals, criteria, and pathways needed to attain the ambitious net zero energy goals defined by California and

  2. Seismic Analysis for Rigid-Framed Prestressed Reinforced Concrete Bridge in Tianjin Light Railway

    Institute of Scientific and Technical Information of China (English)

    丁阳; 李楠; 李忠献

    2004-01-01

    The seismic analysis of a rigid-framed prestressed concrete bridge in Tianjin Light Railway is performed. A 3-D dynamic finite element model of the bridge is established considering the weakening effect caused by the soft soil foundation. After the dynamic characteristics are calculated in terms of natural frequencies and modes, the seismic analysis is carried out using the modal response spectrum method and the time-history method, respectively. Based on the calculated results, the reasonable design values are finally suggested as the basis of the seismic design of the bridge, and meanwhile the problems encountered were also analyzed. Finally, some conclusions are drawn as: 1) Despite the superiority of rigid-framed prestressed concrete bridge, the upper and lower ends of the piers of the bridge are proved to be the crucial parts of the bridge, which are easily destroyed under designed earthquake excitations and should be carefully analyzed and designed; 2) The soft soil foundation can possibly result in rather weakening of the lateral rigidity of the rigid-framed bridge, and should be paid considerable attention; 3) The modal response spectrum method, combined with time-history method, is suggested for the seismic analysis in engineering design of the rigid-framed prestressed concrete bridge.

  3. Probabilistic seismic response and reliability assessment of isolated bridges

    Institute of Scientific and Technical Information of China (English)

    Giuseppe Carlo Marano

    2005-01-01

    Bridge seismic isolation strategy is based on the reduction of shear forces transmitted from the superstructure to the piers by two means: shifting natural period and earthquake input energy reduction by dissipation concentrated in protection devices. In this paper, a stochastic analysis of a simple isolated bridge model for different bridge and device parameters is conducted to assess the efficiency of this seismic protection strategy. To achieve this aim, a simple nonlinear softening constitutive law is adopted to model a wide range of isolation devices, characterized by only three essential mechanical parameters. As a consequence of the random nature of seismic motion, a probabilistic analysis is carried out and the time modulated Kanai-Tajimi stochastic process is adopted to represent the seismic action. The response covariance in the state space is obtained by solving the Lyapunov equation for a stochastic linearized system. After a sensitivity analysis, the failure probability referred to extreme displacement and the mean value of dissipated energy are assessed by using the introduced stochastic indices of seismic bridge protection efficiency. A parametric analysis for protective devices with different mechanical parameters is developed for a proper selection of parameters of isolation devices under different situations.

  4. Docks and Piers, Published in 2008, 1:1200 (1in=100ft) scale, Brown County, WI.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2008. Data by this publisher...

  5. Apparent Sea Level Rise due to Loading of the Atlantic City Pier by Spectators Viewing (1929-1978) Diving Horses

    Science.gov (United States)

    Galvin, C.

    2012-12-01

    Cyril Galvin, Coastal Engineer Springfield, Virginia 22150 USA Since 1911, the Steel Pier at Atlantic City, New Jersey, has been the site of the Atlantic City tide gauge, except for two intervals: 1911-1921 when the gauge was at the Million Dollar Pier in Atlantic City, and 1985-1991 when the gauge was at the Ventnor Fishing Pier (see Table 2, Zervos, 2009). By design, the Steel Pier was an amusement pier, and its most famous amusement was the Diving Horses: they dove bareback with a woman rider from a platform about 40 feet above sea level. They did that between 1929 and 1978, except for seven years - a post-war period, 1945 to 1953, when diving was suspended. The popularity of the diving horses is recorded on photos of crowds which occupied the bleachers at the seaward end of the pier to view the diving horses. By my count, the crowd pictured in the end papers of the book by Steve Liebowitz (2009) was about 4000 people. Typically, there were multiple shows daily. The weight of the crowd, estimated from the count of the crowd, was about 150 tons. This weight was loaded down on the piles by the crowd of spectators, and unloaded between shows of the diving horses. Most of the piles supporting the pier deck were imbedded in sand newly deposited since 1850. Using Atlantic City sea levels from the PSMSL data base and historical facts from Liebowitz (2009), and beginning with a 1912 start of the tide gauge, the apparent sea level rose at a rate of 3.1mm/yr until 1929 when the horses began diving. With the 1929 start of diving, the apparent sea level rise tripled, averaging 9.4 mm/yr until the act was suspended in 1945. In the 1945-1953 interval, when the horses did not dive (no crowds on the pier), apparent sea level fell (sea level FELL) at a rate of -1.6 mm/yr. The horses resumed diving in 1953, when the apparent sea level resumed at a rate of 4.0mm/yr. This 4.0 mm/yr is identical to the longtime sea level trend (1911-2006) from Zervos (2009) of 3.99mm/yr The history

  6. Damage analysis and seismic retrofitting of a continuous prestressed reinforced concrete bridge

    Directory of Open Access Journals (Sweden)

    Nicola Caterino

    2014-12-01

    Full Text Available The seismic analysis and retrofit of prestressed reinforced concrete bridge is discussed by considering a real case of a viaduct still in use. The unique features of this bridge make this type of bridge particularly interesting, either structurally or architecturally. The paper begins with the analysis of certain particular structural deficiencies that emerged during the viaduct operation. The results of the analysis indicate that the structural performance can be enhanced by only modifying the support devices. The primary structural components are not required to be involved in the retrofitting process. Using the modern seismic code, the upgrading of the viaduct performance is obtained by replacing the old bearing devices on the piers and existing viscous dampers connected abutments to the deck with new modernised ones.

  7. Damage investigation of girder bridges under the Wenchuan earthquake and corresponding seismic design recommendations

    Institute of Scientific and Technical Information of China (English)

    Li Jianzhong; Peng Tianbo; Xu yan

    2008-01-01

    An investigation of girder bridges on National Highway 213 and the Doujiangyan-Wenchuan expressway after the Wenchuan earthquake showed that typical types of damage included:span collapses due to unseating at expansion joints;shear key failure;and damage of the expansion joint due to the slide-induced large relative displacement between the bottom of the girder and the top of the laminated-rubber bearing.This slide,however,can actually act as a form of isolation for the substructure,and as a result,the piers and foundation of most of the bridges on state route 213 suffered minor damage.The exception was the Baihua Bridge,which suffered severe damage.Corresponding seismic design recommendations are presented based on this investigation.

  8. Earthquake Response Analysis of Approach Bridge of Suramadu Sea-Crossing Bridge%苏拉马都大桥引桥抗震分析

    Institute of Scientific and Technical Information of China (English)

    郭河; 范轶峰

    2011-01-01

    苏拉马都大桥是印度尼西哑的一座特大型桥梁,其引桥为预应力混凝土连续箱梁结构,通过V形墩与主桥相连.由于桥址处抗震设防烈度较高,又是跨越马都拉海峡的特大型桥梁,其抗震性能尤为重要.采用两水平的抗震设计方法,从地震输入、地震反应谱分析、非线性时程分析、结构的抗震性能验算等方面对苏拉马都大桥引桥的抗震性能进行分析,结果表明,在2 500年1重现期的地震作用下,该桥的抗震性能均满足抗震设防要求.%Surammadu Bridge is an especially large bridge in Indonesia. Its structure style is prestressed concrete continuous box bridge and links with the main bridge by V-style pier. The seismic performance of Suramadu Bridge is particularly important because of the bridge across the Madula Strait and the high seismic intensity at the bridge site. In this paper, based on the antiseismic design of Suramadu Approach Bridge, seismic behavior of cable-stayed bridge is investigated by two-level earthquake-resistance method from the seismic input, the analysis of earthquake response spectrum, the analysis of nonlinear time history and the checking of structural earthquake-resistance performance. It is indicated that, the resistance of Suramadu Approach Bridge is larger than the requirement under the 2 500-year recurrence interval (2% in 50year) earthquake load.

  9. HYDRAULIC CHARACTERISTICS OF WATER-WINGS FOR THE MIDDLE-PIER OF A DISCHARGE TUNNEL

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; CAI Chang-guang; JI Wei; RUAN Shi-ping

    2006-01-01

    Water-wings, induced by the middle-pier placed in the inlet of a discharge tunnel, have harmful effects on the operation of the discharge tunnel.Based on dimensional analysis and physical model tests, the hydraulic characteristics of water-wings were investigated and their causes were analyzed in this study.The results show that the height and length of the water-wings increased with the increase of three factors, i.e., the Froude number Frd of the outlet of the pressure section, the depth Hc of the water surface concave at the end of the middle-pier, and the impact length Li of the two flows after this end.

  10. RELATIONSHIP OF FIRST STEP HEIGHT, STEP SLOPE AND CAVITY IN X-SHAPED FLARING GATE PIERS

    Institute of Scientific and Technical Information of China (English)

    WANG Bo; WU Chao; HU Yao-hua; MO Zheng-yu

    2007-01-01

    The energy dissipation of X-shaped flaring gate piers ahead of a stepped spillway was adopted in the Suofengying Hydroplant. Under the circumstance that the first step is higher than others, at the step surface an aerated cavity occured behind piers. The interaction of the weir head, the elevation difference between crest and chamber outlet, the first step height, the slopes of weir end and step, and the size of cavity, was investigated, the expression was derived to characterize their relationship, and the corresponding curves were plotted. The comparison of the calculated and simulated results with the measured data was performed. When the slopes of step and weir end are equivalent, the relative height difference between the first and second steps becomes the main factor influencing the aerated cavity. These findings may be useful in practical applications.

  11. Bridge recognition based on Gabor filter in forward-looking infrared images

    Science.gov (United States)

    Liu, Songlin; Sun, Gang; Niu, Zhaodong; Chen, Zengping

    2013-10-01

    Conventional methods often assume that water region is homogeneous and bridge is brighter than background. They usually recognize target by parallel lines detection. But grayscale of bridge has bipolar problem in FLIR images due to interference of complex background and constraints of imaging conditions, which means that it can be greater or lower than river. Furthermore, water is not a homogeneous area as a whole because of the interference of water clutter and shoals. This paper proposes a novel algorithm of bridge recognition based on Gabor filter. Firstly, we obtain target ROI by extracting the horizontal line. And then ROI sub-images are enhanced by Gabor filter and target polarity is determined by bridge body detection. Finally, bridge recognition can be achieved by pier detection according to the target polarity and location of bridge body. Experimental results of nearly 3000 frames show that the proposed algorithm can effectively overcome problems such as bipolar target and low image contrast. It offers a good practicability and accuracy in bridge recognition in FLIR images.

  12. Non-rigid connector in fixed partial dentures with pier abutment: An enigma simplified

    OpenAIRE

    Prince Kumar; Vishal Singh; Roshni Goel; Harkanwal P Singh

    2012-01-01

    In the fixed partial denture (FPD) prosthesis with rigid connectors, forces of mastication are transmitted to the terminal retainers, which make the middle abutment act as a class I lever fulcrum. This techno-clinical cycle often causes failure of the fixed partial dentures. To overcome this dilemma, a non-rigid connector may be incorporated on the distal aspect of the middle (pier) abutment. The non-rigid connector counterbalances the effects of these forces of leverage. This clinical report...

  13. Silicone-modified graphene oxide fillers via the Piers-Rubinsztajn reaction

    DEFF Research Database (Denmark)

    Zhang, Jianfeng; Liang, Shuai; Yu, Liyun;

    2016-01-01

    While graphene or graphene oxide can make significantimprovements in the properties of a wide variety of polymericmaterials, their incorporation can be challenged byincompatibility with the polymeric matrix. The modification ofgraphene oxide with silicones or silanes using the Piers......-Rubinsztajn reaction improves dispersibility in nonpolar materials,including organic solvents and silicone pre-elastomers. Ahigh loading (up to 10 wt %) of modified graphene oxide insilicone elastomers could be achieved, which resulted inenhanced mechanical performance and reduced gas permeability....

  14. 桥梁抗震结构计算%Anti-seismic Structure Calculation of Bridge

    Institute of Scientific and Technical Information of China (English)

    许鹏

    2012-01-01

    依托工程实例,对桥墩进行抗震计算,不仅可以更深入的理解抗震规范,而且定性地总结出利于结构抗震并且经济可行的结构处理方法。%Based on project case,anti-seismic calculation of bridge pier is performed.Therefore,not only can anti-seismic code be understood deeper,but also economic and feasible structure treatment method in favour of structure seismic resistance can be summarized qualitatively.

  15. 跨营业线群门式墩施工方案及吊装费用分析%Group Door Type Pier Construction Scheme and Hoisting Fee Analysis across Railroad Business Line

    Institute of Scientific and Technical Information of China (English)

    颜嘉

    2012-01-01

    合福铁路蚌福联络线蒙城北路特大桥46号~53号墩上跨6条既有铁路线,施工空间狭小,对施工安全要求高,为此初步拟定了门式墩钢梁现场拼装施工方案和大吨位起重机吊装方案。经过分析与比较,750t覆带式起重机吊装方案满足施工要求。为此对750t起重机吊装按台班费、进出场费及安拆费、辅助工程费3部分进行分析与测算。%He - Fu railway Beng - Fu connecting lines, MengCheng north road large bridge road, 46 - 53 # piers are across 6 the existing railway lines. The construction space is narrow and the construction safety requirement is high. Therefore, preliminary draws up the door type steel pier assembling construction schemes and large tonnage crane hoisting plan. Through analysis and comparison, 750t crawler crane hoisting plan meets the construction requirements. The 750t crane hoisting is analyzed and calculated according to machine fee , entering and going out field fee and installing and disassembly fee and ancillary works fee.

  16. Circulation characteristics of horseshoe vortex in scour region around circular piers

    Directory of Open Access Journals (Sweden)

    Subhasish DAS

    2013-01-01

    Full Text Available This paper presents an experimental investigation of the circulation of the horseshoe vortex system within the equilibrium scour hole at a circular pier, with the data measured by an acoustic Doppler velocimeter (ADV. Velocity vector plots and vorticity contours of the flow field on the upstream plane of symmetry (y = 0 cm and on the planes ±3 cm away from the plane of symmetry (y = ±3 cm are presented. The vorticity and circulation of the horseshoe vortices were determined using the forward difference technique and Stokes theorem, respectively. The results show that the magnitudes of circulations are similar on the planes y = 3 cm and y = –3 cm, which are less than those on the plane y = 0 cm. The circulation decreases with the increase of flow shallowness, and increases with the densimetric Froude number. It also increases with the pier Reynolds number at a constant densimetric Froude number, or at a constant flow shallowness. The relative vortex strength (dimensionless circulation decreases with the increase of the pier Reynolds number. Some empirical equations are proposed based on the results. The predicted circulation values with these equations match the measured data, which indicates that these equations can be used to estimate the circulation in future studies.

  17. Longitudinal force in continuously welded rail on long-span tied arch continuous bridge carrying multiple tracks

    Institute of Scientific and Technical Information of China (English)

    YAN Bin; DAI Gong-lian; GUO Wen-hua; XU Qing-yuan

    2015-01-01

    Considering arch rib, lateral brace, suspender, girder, pier and track position, the model for the interaction between long-span tied arch continuous bridge and multiple tracks was established by using steel-concrete composite section beam element to simulate concrete-filled steel tube (CFST) arch rib, using the beam element with rigid arm to simulate the prestressed concrete girder and using nonlinear bar element to simulate longitudinal constraint between track and bridge. Taking a (77+3×156.8+77) m tied arch continuous bridge with four tracks on the Harbin-Qiqihar Passenger Dedicated Line as an example, the arrangement of continuously welded rail (CWR) was explored. The longitudinal force in CWR on the tied arch continuous bridge, the pier top horizontal force and torque due to the unbalance load case, were analyzed under the action of temperature, vertical live load, train braking and wind load. Studies show that, it can significantly reduce track displacement to set the track expansion devices at main span arch springing on both sides; the track stress due to arch temperature variation can reach 40.8 MPa; the track stress, pier top horizontal force and torque are related to the number of loaded tracks and train running direction, and the bending force applied to unloaded track is close to the loaded track, while the braking force applied to unloaded track is 1/4 to 1/2 of the loaded track; the longitudinal force of track due to the wind load is up to 12.4 MPa, which should be considered.

  18. Cable Supported Bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    Cable supported bridges in the form of suspension bridges and cable-stayed bridges are distinguished by their ability to overcome large spans.The book concentrates on the synthesis of cable supported bridges, covering both design and construction aspects. The analytical part covers simple methods...... to quantify the different structural configurations and allows a preliminary optimization of the main structure.Included are the most recent advances in structural design, corrosion protection of cables, aerodynamic safety, and erection procedures....

  19. Construction craft of climb molding of variable cross-section high piers cantilever support%变截面高墩悬臂支架轻型爬模施工工艺

    Institute of Scientific and Technical Information of China (English)

    王利强

    2011-01-01

    Combining with piers climb molding construction practice of Hukou of the Yellow River large Bridge of Qing-Lan highway Lin-Ji section, summarized the construction technology of construction process, separately made introduction from the process characteristics, process principle, construction key points and other aspects, so as to accumulate relevant construction experience and guide engineering practice.%结合青兰高速临吉段壶口黄河特大桥的墩身爬模施工实践,对施工过程中的施工工艺做了总结,分别从工艺特点、工艺原理、施工要点等方面作了说明,以积累相关施工经验,指导工程实践。

  20. 城市轨道交通双线桥上无缝线路挠曲力研究%Analysis of the Flexural Forces in CWR on Double-track Bridges of Urban Rail Transit

    Institute of Scientific and Technical Information of China (English)

    王冬梅; 倪向阳; 王慧珺

    2012-01-01

    针对城市轨道交通中新应用的双线U型梁和传统的双线箱型梁两种不同形式桥梁,用有限元法计算分析桥上无缝线路附加挠曲力及附加挠曲位移的分布,着重研究线路纵向阻力、桥梁跨度和桥墩刚度等参数变化对桥上无缝线路钢轨受力、桥墩受力及桥梁挠度的影响.研究结果表明,线路纵向阻力、桥梁跨度对钢轨挠曲力的影响较大,而桥墩纵向刚度对钢轨挠曲力的影响较小,为城市轨道交通设计提供理论参考依据.%Two types of urban rail transit double-track bridges are considered including the new type U-beam bridge and the traditional type box-girder bridge. The additional flexural forces and displacement distribution in CWR on the bridges have been calculated by finite element method. This paper carried out a detailed analysis on the flexural forces in tracks, the pier forces and bridge deflections owing to the changes in the longitudinal resistance, bridge spans and pier stiffness. Results showed that longitudinal resistance, bridge spans affect the rail additional flexural forces to a larger extent and the pier stiffness less affects the rail additional flexural forces. These results can provide a theoretical basis for the design of urban rail transit bridges.

  1. Il Decameron de Pier Paolo Pasolini: da prosa medieval ao roteiro cinematográfico Il Decameron by Pier Paolo Pasolini: from the medieval prose to the screenplay

    Directory of Open Access Journals (Sweden)

    Paula Regina Siega

    2012-12-01

    Full Text Available Este artigo situa-se no campo das teorias da recepção e trabalha com o conceito de "leitura como ato criativo", desenvolvido por Hans Robert Jauss e Wolfgang Iser. Interpretando o roteiro como estrutura textual produtora de imagens literárias, elegemos como objeto de estudo o texto Il Decameron, escrito por Pier Paolo Pasolini com base na obra de Giovanni Boccaccio. Na análise, investigamos os efeitos poéticos produzidos pela releitura do texto medieval, indicando as transformações que o realismo boccacciano assume na linguagem de Pasolini. Para tanto, evidenciamos a importância que as realidades do sexo e da morte adquirem no roteiro, observando como o autor conjuga estes temas às reflexões que faz sobre a própria contemporaneidade.Questo articolo è situato nel campo delle teorie della ricezione e lavora con il concetto di "lettura come atto creativo", sviluppato da Hans Robert Jauss e Wolfgang Iser. Nell'interpretare la sceneggiatura come struttura testuale produttrice di immagini letterarie, scegliamo come oggetto di studio il testo Il Decameron, scritto da Pier Paolo Pasolini basato sull'opera di Giovanni Boccaccio. Nell'analisi, investighiamo gli effetti poetici prodotti dalla rilettura del testo medioevale indicando le trasformazioni che il realismo boccacciano assume nel linguaggio di Pasolini. Pertanto, evidenziamo l'importanza che le realtà del sesso e della morte acquisiscono nella sceneggiatura, osservando come l'autore concilia questi temi con le riflessioni che fa sulla propria contemporaneità.This article is situated in the field of the reception theories and works with the concept of "reading as creative act", developed by Hans Robert Jauss and Wolfgang Iser. Seeing in the screenplay a textual structure that produces literary images, we choose as our object the text Il Decameron, written by Pier Paolo Pasolini based on Boccaccio's work. In the analysis, we investigate the poetic effects produced by the rereading of

  2. Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

    Directory of Open Access Journals (Sweden)

    You-Liang Ding

    2015-01-01

    Full Text Available Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge’s abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

  3. Finite element model updating of a prestressed concrete box girder bridge using subproblem approximation

    Science.gov (United States)

    Chen, G. W.; Omenzetter, P.

    2016-04-01

    This paper presents the implementation of an updating procedure for the finite element model (FEM) of a prestressed concrete continuous box-girder highway off-ramp bridge. Ambient vibration testing was conducted to excite the bridge, assisted by linear chirp sweepings induced by two small electrodynamic shakes deployed to enhance the excitation levels, since the bridge was closed to traffic. The data-driven stochastic subspace identification method was executed to recover the modal properties from measurement data. An initial FEM was developed and correlation between the experimental modal results and their analytical counterparts was studied. Modelling of the pier and abutment bearings was carefully adjusted to reflect the real operational conditions of the bridge. The subproblem approximation method was subsequently utilized to automatically update the FEM. For this purpose, the influences of bearing stiffness, and mass density and Young's modulus of materials were examined as uncertain parameters using sensitivity analysis. The updating objective function was defined based on a summation of squared values of relative errors of natural frequencies between the FEM and experimentation. All the identified modes were used as the target responses with the purpose of putting more constrains for the optimization process and decreasing the number of potentially feasible combinations for parameter changes. The updated FEM of the bridge was able to produce sufficient improvements in natural frequencies in most modes of interest, and can serve for a more precise dynamic response prediction or future investigation of the bridge health.

  4. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  5. Assessing potential scour using the South Carolina bridge-scour envelope curves

    Science.gov (United States)

    Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral

    2016-09-30

    SummaryBridge-scour equations presented in the Federal Highway Administration Hydraulic Engineering Circular No. 18 reflect the current state-of-the practice for predicting scour at bridges. Although these laboratory-derived equations provide an important resource for assessing scour potential, there is a measure of uncertainty when applying these equations to field conditions. The uncertainty and limitations have been acknowledged by laboratory researchers and confirmed in field investigations.Because of the uncertainty associated with bridge-scour equations, HEC-18 recommends that engineers evaluate the computed scour depths obtained from the equations and modify the resulting data if they appear unreasonable. Perhaps the best way to evaluate the reasonableness of predicted scour is to compare it to field measurements of historic scour. Historic field data show scour depths resulting from high flows and provide a reference for evaluating predicted scour. It is rare, however, that such data are available at or near a site of interest, making the evaluation of predicted scour as compared to field data difficult if not impossible. Realizing the value of historic scour measurements, the U.S. Geological Survey (USGS), in cooperation with the South Carolina Department of Transportation (SCDOT), conducted a series of three field investigations to collect historic scour data with the goal of understanding regional trends of scour at riverine bridges in South Carolina.Historic scour measurements, including measurements of clear-water abutment, contraction, and pier scour, as well as live-bed contraction and pier scour, were made at more than 200 bridges. These field investigations provided valuable insights into regional scour trends and yielded regional bridge-scour envelope curves that can be used as supplementary tools for assessing all components of scour at riverine bridges in South Carolina.The application and limitations of these envelope curves were documented in

  6. High voltage shore connections. Application in piers and power supply ships

    OpenAIRE

    Pons Roser, Aina

    2016-01-01

    The objective of this project is to study the behavior of a High Voltage Shore Connection, a useful system to carry electrical power from shore to ship and backwards, while it is berthed at piers. This will be done by designing a system for a port, able to be connecting four ships at the same time to a shore power source. With this design, simulations will be performed. The results in regular operation conditions and in special situations will be analyzed, and they will be compared with the q...

  7. Circulation characteristics of horseshoe vortex in scour region around circular piers

    OpenAIRE

    DAS, Subhasish; Das, Rajib; Mazumdar, Asis

    2013-01-01

    This paper presents an experimental investigation of the circulation of the horseshoe vortex system within the equilibrium scour hole at a circular pier, with the data measured by an acoustic Doppler velocimeter (ADV). Velocity vector plots and vorticity contours of the flow field on the upstream plane of symmetry (y = 0 cm) and on the planes ±3 cm away from the plane of symmetry (y = ±3 cm) are presented. The vorticity and circulation of the horseshoe vortices were determined using the forwa...

  8. Destrutturare le maiuscole. Pensiero debole, Italian Theory e politica. Conversazione con Pier Aldo Rovatti

    Directory of Open Access Journals (Sweden)

    Pier Aldo Rovatti

    2014-06-01

    Full Text Available The conversation focuses on the social and political role of the philosopher nowadays. Pier Aldo Rovatti discusses about the growing philosophical movement called “Italian Theory” while revisiting his own recent intellectual path. The italian philosopher retraces the cultural experience of the “pensiero debole”, whereof he has been one of the two promoters, and underlines the intellectual and political fight, against all the so-called universal truths (and ideological violences, inspired by this philosophical trend at the beginning of the Eighties. The interview ends with a discussion about the dawning perspectives of the political-philosophical action in the post-modern age.

  9. Nonlinear Stability Analysis of a Composite Girder Cable-Stayed Bridge with Three Pylons during Construction

    Directory of Open Access Journals (Sweden)

    Xiaoguang Deng

    2015-01-01

    Full Text Available Based on the nonlinear stability analysis method, the 3D nonlinear finite element model of a composite girder cable-stayed bridge with three pylons is established to research the effect of factors including geometric nonlinearity, material nonlinearity, static wind load, and unbalanced construction load on the structural stability during construction. Besides, the structural nonlinear stability in different construction schemes and the determination of temporary pier position are also studied. The nonlinear stability safety factors are calculated to demonstrate the rationality and safety of construction schemes. The results show that the nonlinear stability safety factors of this bridge during construction meet the design requirement and the minimum value occurs in the maximum double cantilever stage. Besides, the nonlinear stability of the structure in the side of edge-pylon meets the design requirement in the two construction schemes. Furthermore, the temporary pier can improve the structure stability, effectively, and the actual position is reasonable. In addition, the local buckling of steel girder occurs earlier than overall instability under load in some cable tension stages. Finally, static wind load and the unbalanced construction load should be considered in the stability analysis for the adverse impact.

  10. INVESTIGATION OF VEHICLE IMPACT FORCE ON BRIDGE WITH ROUGH RIDING SURFACE

    Directory of Open Access Journals (Sweden)

    O. L. Verbitskaya

    2014-01-01

    Full Text Available Nowadays heavy vehicles constitute a considerable volume in the transportation flow on the territory of the Republic of Belarus and bridge inequalities significantly increase a load on their bearing elements and cause a vibration in bridge superstructures. This leads to rapid wear and reduction in time between bridge repairs. The given problem has been insufficiently studied and it is considered as an actual one. Revision of analytical models is required in order to make prediction and evaluation of bridge structure wear. These models must take into account a dynamic impact of heavy vehicles caused by their movement on bridge rough riding surface.The purpose of scientific investigations is to develop a dynamic interactional model of a vehicle and a bridge plate. The paper proposes such dynamic model that permits to investigate impact forces of a heavy vehicle on bridge superstructures which have been initiated by bridge traffic-way inequalities. Weight of an vehicle and plate, rigidity and viscous damping of vehicle suspensions, a plate and piers have been taken into account while making the required calculations.An analysis of free oscillatory motions of the plate and vehicle have been carried out with due account of viscous damping. A dynamic interactional calculation for a vehicle and a plate has been made in the paper. Character of plate oscillatory motions has been determined at various parameters of the dynamic model. In this case non-linearity of reinforced concrete plate deformation has been taken into account and its calculation has been executed in accordance with the norms of the Republic of Belarus. The calculations have made it possible to obtain dynamic interaction coefficients of front axle wheels and bridge plate at various bench heights and also investigate its influence on maximum bending moments in plate sections.

  11. 高速公路桥梁应急抢险加固方案分析%Analysis of Emergency Rescue and Reinforcement Scheme for Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    周礼平

    2016-01-01

    A blasting company was taking the blasting construction in bridge 0#, and the stones flying out hit 3# pier causing 3# pier severely damaged:the pier was smashed into irregular holes with area of 3m x 2.3m, which had a threat to the safety of a highway bridge so that maintenance and reinforcement were needed. The author according to the test report took the maintenance and reinforcement design;the major project is that on the side of 3# pier smashed reinforcing bars were fixed up, reinforcing bars at the smashed place should be repair, and following the first partition of pier column C45 self compacting concrete was perfused and cavities were sealed. After the completion of the emergency rescue and maintenance reinforcement construction, the load test results met the operating requirements of level -Ⅰhighway, and the effect was good. The project that perfusion of self-compacting concrete was perfused into the hollow partition of pier column 3# and pier column 1# plate was an innovation of pier reinforcement scheme with enlarged cross-section, innovation points mainly including: improving the stiffness of the pier, and due to self-compacting concrete used in pier column reinforcement, saving the template so as to save cost for the owners.%某高速公路桥梁由于爆破公司在大桥0#台处进行爆破施工,飞出来的石块砸中3#桥墩,造成3#桥墩严重受损,墩柱被砸成不规则孔洞,空洞面积为3m×2.3m。对桥梁安全构成威胁,需要进行维修加固,作者根据检测报告进行维修加固设计,主要方案为在3#墩柱被砸一侧布置钢筋,被砸处钢筋进行修复,墩柱第一道隔板以下灌注C45自密实混凝土并封闭空洞。应急抢险维修加固施工完成后,荷载试验检测结果满足公路-Ⅰ级使用要求,应急抢险维修加固效果良好,其中墩柱3#墩柱1#隔板空心部分灌注自密实混凝土的方案是墩柱增大截面加固方案的创新,创新点

  12. Analysis of Seismic Response and Seismic Checking in A Long-span Continuous Beam Bridge on a High-speed Railway%高速铁路大跨连续梁桥地震反应分析及抗震校核

    Institute of Scientific and Technical Information of China (English)

    张永亮; 孙建飞; 徐家林

    2013-01-01

    针对高速铁路大跨连续梁桥的结构特点,结合三水准的抗震设防目标,给出了各水准下桥梁的抗震验算指标.采用反应谱法及弹塑性时程反应分析法对一实桥进行了地震反应分析及抗震性能评价.结果表明固定墩控制该桥的抗震设计.在多遇地震作用下固定墩处于弹性状态;在罕遇地震作用下固定墩纵向进入塑性,但位移延性系数小于规范容许值,结构具有较高的延性储备.该桥的抗震能力满足三水准抗震设防目标.%Considering that earthquakes occur frequently in China,four vertical and four horizontal high-speed railway networks are planned,and 23 provincial capital cities and two-thirds of the cities with populations of more than a million are located in regions of high seismic intensity,seismic design is the controlling factor in the design of high-speed railway bridges.The differences between a high-speed railway bridge and a highway or common railway bridge lie in the following aspects:First,pier,bearing system,and displacement restrictions are required to strictly ensure that high-speed trains remain on the rails.Second,bridges make up a large proportion of the high-speed railway,and most of these bridges are viaducts and long.Third,the high-speed railway will have a major impact,being traffic intensive,high speed,high cost,and so on.Fourth,gravity piers(or hollow piers)are generally used in the substructures of such bridges,and these piers often have large section size and low reinforcement ratio.The long-span continuous bridge is the most widely used bridge type in Chinese high-speed railway construction,and the structural form of "multiple spans as one unit" is often used in this bridge type,with only one fixed pier per unit.Under earthquake force,the inertial force of the superstructure is mainly exerted on the fixed pier,so the fixed pier must meet the requirements of strength and ductility.For this reason,most fixed piers of long

  13. Monitoring of levees, bridges, pipelines, and other critical infrastructure during the 2011 flooding in the Mississippi River Basin: Chapter J in 2011 floods of the central United States

    Science.gov (United States)

    Densmore, Brenda K.; Burton, Bethany L.; Dietsch, Benjamin J.; Cannia, James C.; Huizinga, Richard J.

    2014-01-01

    more prone to erosion or scour. Data collected from multibeam echosounder hydrographic surveys at selected bridges aided State agencies in evaluating the structural integrity of the bridges during the flood, by assessing the amount of scour present around piers and abutments. Hydrographic surveys of the riverbed detected scour depths ranging from zero (no scour) to approximately 5.8 meters in some areas adjacent to North Dakota bridge piers, zero to approximately 6 meters near bridge piers in Nebraska, and zero to approximately 10.4 meters near bridge piers in Missouri. Substructural support elements of some bridge piers in North Dakota, Nebraska, and Missouri that usually are buried were exposed to moving water and sediment. At five Missouri bridge piers the depth of scour left less than 1.8 meters of bed material between the bottom of the scour hole and bedrock. State agencies used this information along with bridge design and construction information to determine if reported scour depths would have a substantial effect on the stability of the structure. Multibeam echosounder hydrographic surveys of the riverbed near pipeline crossings did not detect exposed pipelines. However, analysis of the USGS survey data by pipeline companies aided in their evaluation of pipeline safety and led one company to further investigate the safety of their line and assisted another company in getting one offline pipeline back into operation. Multibeam echosounder hydrographic surveys of the banks, riverbed, and underwater infrastructure at Omaha Public Power District power plants documented the bed and scour conditions. These datasets were used by Omaha Public Power District to evaluate the effects that the flood had on operation, specifically to evaluate if scour during the peak of the flood or sediment deposition during the flood recession would affect the water intake structures. Hydrographic surveys at an Omaha Public Power District electrical transmission tower documented scour so

  14. Analysis on influence of seismic travelling wave effect on semi-active control for long-span rigid-continuous bridge

    Institute of Scientific and Technical Information of China (English)

    QI Xing-jun; LI Xiao-jun; ZHOU Guo-liang

    2006-01-01

    The analysis approach of semi-active control for long-span rigid-continuous bridge under seismic travelling wave input is established. Magnetorheological dampers are set on the positions of the bridge bearings. The semi-active control calculation and analysis are performed for a five-span rigid-continuous bridge under seismic travelling waves with different apparent surface velocities. The results indicate that travelling wave effect remarkably influences the uncontrolled seismic responses, the semi-active control seismic responses and vibration control effects for the long-span rigid-continuous bridge. It is disadvantageous to the responses of the beams and the piers under the travelling wave input with lower apparent surface velocity, and travelling wave effect can decrease the vibration control effects evidently. Therefore, the travelling wave effect should be considered for the selection of the parameter values of semi-active control system in order to get the designing control effect.

  15. An investigation of spatial variation of suspended sediment concentration induced by a bay bridge based on Landsat TM and OLI data

    Science.gov (United States)

    Cai, LiNa; Tang, DanLing; Li, CongYing

    2015-07-01

    This study investigates the spatial variation of suspended sediment concentration (SSC) induced by Hangzhou Bay Bridge (HBB) in the coastal waters of the East China Sea. Based on Landsat Thematic Mapper (TM), Operational Land Imager (OLI) data and in-situ measurements, spectral characteristics of waters in Hangzhou Bay and SSC retrieved from near infrared single band have been analyzed. The results revealed significant difference of SSC in the water on two sides of HBB. SSC increases downstream of the bridge under conditions of low turbidity (SSC 400 mg l-1) upstream. This study shows that the interaction of bridge piers and currents has important influences on SSC distribution by inducing hydrodynamic factors and by changing suspended sediment transport. Remotely sensed data with high spatial resolution as TM and OLI can be applied to investigate SSC variations induced by a bridge in the bay area.

  16. Hydrology and modeling of flow conditions at Bridge 339 and Mile 38-43, Copper River Highway, Alaska

    Science.gov (United States)

    Brabets, Timothy P.

    2012-01-01

    The Copper River basin, the sixth largest watershed in Alaska, drains an area of 24,200 square miles in south-central Alaska. This large, glacier-fed river flows across a wide alluvial fan before it enters the Gulf of Alaska. The Copper River Highway, which traverses the alluvial fan, has been affected by channel planform reconfiguration. Currently (2012), two areas of the Copper River Highway are at risk: at Mile 38-43, the road grade is too low and the highway could be flooded by high flows of the Copper River, and at Mile 36, the main channel of the Copper River has migrated directly toward Bridge 339. Because Bridge 339 was not designed and built to convey the main flow of the Copper River, as much as 50 feet of scour occurred at the piers in 2011. The piers can no longer absorb the lateral or vertical loads, resulting in closure of the bridge and the Copper River Highway. The U.S. Geological Survey Flow and Sediment Transport with Morphologic Evolution of Channels (FaSTMECH) model was used to simulate the flow of the Copper River and produce simulations of depth, water-surface elevation, and velocity. At the Mile 38-43 area, FaSTMECH was used to analyze the effects of raising the road grade 5 feet, and at Mile 36, FaSTMECH was used to analyze the effects of constructing a channel to divert flow away from Bridge 339. Results from FaSTMECH indicate that if raising the road grade 5 feet in the Mile 38-43 area, a flood with an annual exceedance probability of 2 percent (400,000 cubic feet per second) would not overtop the highway. In the Bridge 339 area, results from FaSTMECH indicate that a design channel could divert flows as much as 100,000 cubic feet per second away from Bridge 339.

  17. Concrete bridge prioritization system

    OpenAIRE

    Kesselring, Debbie Anne

    1995-01-01

    An alternative method of prioritization for concrete bridge maintenance, repair, and rehabilitation activities is required due to the inability of the current system to manage the increasing nmnber of aging concrete bridges. The Concrete Bridge Prioritization System was proposed because of its ability to address the critical technical parameters of safety and cost benefit in prioritization of funding and work allocation. The analysis includes four parts, service life assessment, s...

  18. Design of Cable-Stayed Bridge of Caofeidian Industry Zone Bridge No.1%曹妃甸工业区1号桥斜拉桥设计

    Institute of Scientific and Technical Information of China (English)

    陈亮; 卢永成; 周伟翔; 邵长宇

    2011-01-01

    The Caofeidian Industry Zone Bridge No. 1 is composed of navigable span bridge, non-navigable span bridges and approach bridges and is located in the cold and strong earthquake region in the northern part of China. A summarized account of the design of the navigable span bridge of the bridge is presented herewith. In accordance with the construction conditions and landscape requirements, the navigable span bridge is designed as a single pylon and single cable plane cable-stayed bridge with span arrangement 2 X 138 m, the pylon is the column pylon in shape of boat sail. The anchorage zone in the pylon is the steel anchor box exposed outside the pylon. The main girder is the steel and concrete composite girder having three cells and a single box. The stay cables are made up of φ7 mm galvanized parallel steel wires and the foundation of the pylon pier is the group pile foundation. The research of seismic resistance of the bridge show that for a major single pylon cable-stayed bridge located in the strong earthquake region, the rigid fixity system of pylon, girder and pier should be possibly avoided in order to reduce seismic response of the bridge structure.%曹妃甸工业区1号桥位于北方寒冷强震区,由通航孔桥、非通航孔桥及引桥组成,综述该桥通航孔桥设计.根据建设条件及景观要求,通航孔桥为跨径2×138 m独塔单索面斜拉桥;桥塔为独柱形,造型为船帆式;索塔锚固区采用外露式钢锚箱方案;主梁采用单箱三室钢-混凝土箱形结合梁;斜拉索采用φ7 mm镀锌平行钢丝;桥塔墩采用群桩基础.抗震性能研究表明,强震区大型独塔斜拉桥应尽量避免采用塔、梁、墩固结体系,以减小桥梁结构的地震响应.

  19. Bridging the Gap

    DEFF Research Database (Denmark)

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska;

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures.......Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures....

  20. Bridging the Gap

    OpenAIRE

    Kramer Overgaard, Majken; Broeng, Jes; Jensen, Monika Luniewska; Murdock, Karen; Schmidt, Iben Julie

    2015-01-01

    Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ventures. Bridging the Gap (BtG) is a 2-year project funded by The Danish Industry Foundation. The goal of Bridging the Gap has been to create a new innovation model which will increase the rate at which Danish universities can spinout new technology ve...

  1. Semiconductor bridge (SCB) detonator

    Science.gov (United States)

    Bickes, Jr., Robert W.; Grubelich, Mark C.

    1999-01-01

    The present invention is a low-energy detonator for high-density secondary-explosive materials initiated by a semiconductor bridge igniter that comprises a pair of electrically conductive lands connected by a semiconductor bridge. The semiconductor bridge is in operational or direct contact with the explosive material, whereby current flowing through the semiconductor bridge causes initiation of the explosive material. Header wires connected to the electrically-conductive lands and electrical feed-throughs of the header posts of explosive devices, are substantially coaxial to the direction of current flow through the SCB, i.e., substantially coaxial to the SCB length.

  2. Grey cast iron as construction material of bridges from the 18th and 19th century

    Directory of Open Access Journals (Sweden)

    J. Rabiega

    2011-04-01

    Full Text Available Many bridges and railroad viaducts, which have been operated at the western and southern regions of Poland, were erected at the end ofthe 18th or beginning of the 19th century. In recent years they undergo overhauls and renovations requiring familiarity with the construction materials they have been made of. It is necessary for estimation of their load capacity (possible reinforcements and determining their suitability for further utilisation. Among the materials in the old bridges the puddled steels and cast irons predominate. Aim of the work is identification and documentation of microstructure and selected properties of the cast irons used for production of parts for the bridge in Łażany, the Old Mieszczański Bridge in Wrocław, the hanging bridge in Ozimek, as well as the columnar piers of the railroad viaduct in Wrocław. Using the methods of light microscopy and scanning electron microscopy, as well as the results of hardness measurements and chemical analysis, it has been shown that the objects have been built of grey cast iron with flake graphite having the ferritic-pearlitic or pearlitic matrix. The diversification of their chemical analysis resulting from the type, size and geometry of the cast parts was indicated.The tested materials fulfil requirements of the contemporary standards related to grey cast irons of the EN-GJL-100 and EN-GJL-150grades.

  3. Vibration based structural assessment of the rehabilitation intervention in r.c. segmental bridge

    Directory of Open Access Journals (Sweden)

    Franchetti Paolo

    2015-01-01

    Full Text Available A vibration based structural assessment campaign was carried out on a r.c. segmental bridge in North East Italy. The bridge has a cantilever static scheme, fixed at the top of the piers and with a hinge at the centre of the span. The particular configuration of the hinge consists in a couple of steel elements, each one composed by a tongue and groove joint. Since the year 1960, the hinge was subjected to consumption and degradation, that caused a malfunctioning of the device. An intervention of rehabilitation of the bridge led to a reinforcement of the existing hinges with the coupling of new metallic devices: new tongue and groove hinges were applied, that by one side allow the horizontal displacements and rotation, by the other side strongly reduce the relative vertical displacements of the two parts of the bridge. A dynamic test campaign was set up in order to assess the effectiveness of the intervention. The principal dynamic parameters were calculated and analysed with respect to the intervention that was realized. The tests clearly showed the effectiveness of the intervention, and helped the designer to have a better understanding of the structural behaviour of the bridge.

  4. Trend of welding robot for bridge construction; Kyoryo ni okeru genba yosetsu no jidoka robot ka

    Energy Technology Data Exchange (ETDEWEB)

    Yasuda, O. [Takada Kiko Co. Ltd., Osaka (Japan)

    1997-12-01

    This paper explains general bridge construction methods and describes future problems therein on automation and robotization of site welding in bridge construction. Site jointing in bridge construction has used high-strength bolt jointing as the mainstream until recently, but adoption of site welding is now increasing. Steel bed plates, box girders, I-shaped girders, and bridge piers have different characteristic requirements in welding volume and plate thickness, to which carbon dioxide arc-welding and submerged-arc welding are used depending on welding postures. Anti-seismic reinforcement construction on RC bridges has started with the Great Hanshin Earthquake as a turning point (steel plates are wound round columns, welded by CO2 arc-welding using the backing strip system, and resin and/or mortar are filled into clearance between RC and the steel plates). This construction requires vertical welding work with welding length as long as 10 m or longer, making the automation and robotization great advantages. For all cases, robotization in site constructions has just begun, whereas a number of problems desired of solution on robots exist, such as high-efficiency welding, and weldable postures the robots can take. 1 ref., 13 figs.

  5. Indian practice on estimation of scour around bridge piers—A comment

    Indian Academy of Sciences (India)

    Umesh C Kothyari

    2007-06-01

    Well-laid foundation is mostly provided in road and railway bridges in India over large and medium-sized rivers. The age-old Lacey–Inglis method is used for estimation of the design scour depth around bridge elements such as pier, abutment, guide bank, spur and groyene. Codal provisions are seen to produce too large a scour depth around bridge elements resulting in bridge sub-structures that lead to increased construction costs. Limitations that exist in the codes of practice are illustrated in this paper using examples. The methods recently developed for estimation of the scour are described. New railway and road bridges are required to be built in large numbers in the near future across several rivers to strengthen such infrastructure in the country. It is strongly felt that provisions in the existing codes of practice for determination of design scour depth require immediate review. The present paper provides a critical note on the practices followed in India for estimating the design scour depth.

  6. Design of Main Bridge of Shuangyudao Bridge in Zhangzhou Development Zone%漳州开发区双鱼岛大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    陶小兰; 李涛; 姚建军

    2013-01-01

    Main bridge of Shuangyudao Bridge in Fujian Zhangzhou Development Zone is a 36m +2×66m +36m cable-stayed bridge with single pylon and double cable planes, and its girders are fish-belly prestressed concrete continuous box girders, cable pylon is twin-dolphin gate-typed steel tower, piers are in elliptic shape and bored pile foundation is adopted. This paper introduces design of all major structures, analyzes stresses on girder, cable pylon, stayed cable and steel anchor box of the bridge by establishing finite-element integral and local computational models and introduces its construction scheme.%福建省漳州开发区双鱼岛大桥主桥为36 m+2×66 m+36 m独塔双索面斜拉桥,主梁采用鱼腹式预应力混凝土连续箱梁,索塔为双鱼门型钢塔,桥墩为椭圆造型,采用钻孔灌注桩基础.介绍该桥各主要结构的设计,通过建立有限元整体计算模型及局部计算模型对该桥主梁、索塔、斜拉索、钢锚箱的受力进行分析并对其施工方案进行介绍.

  7. Principles of Bridge Reliability

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, Andrzej S.

    The paper gives a brief introduction to the basic principles of structural reliability theory and its application to bridge engineering. Fundamental concepts like failure probability and reliability index are introduced. Ultimate as well as serviceability limit states for bridges are formulated...

  8. The floating water bridge

    International Nuclear Information System (INIS)

    When high voltage is applied to distilled water filled in two glass beakers which are in contact, a stable water connection forms spontaneously, giving the impression of a floating water bridge. A detailed experimental analysis reveals static and dynamic structures as well as heat and mass transfer through this bridge

  9. 78 FR 70024 - Draft Environmental Impact Statement for the Modernization and Repair of Piers 2 and 3, Military...

    Science.gov (United States)

    2013-11-22

    ... in the immediate vicinity of Piers 2 and 3; removal and replacement/repair of piles and selected... States Code 4321 et seq.); the Council on Environmental Quality regulations implementing NEPA (40 Code of Federal Regulations Parts 1500-1508), and the Army's regulations implementing NEPA (32 CFR Part 651...

  10. 33 CFR 334.102 - Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area...

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Sandy Hook Bay, Naval Weapons Station EARLE, Piers and Terminal Channel, restricted area, Middletown, New Jersey. 334.102 Section 334.102 Navigation and Navigable Waters CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE DANGER ZONE AND RESTRICTED AREA REGULATIONS...

  11. 汽车撞击桥墩瞬态撞击力的等效静力计算%Equivalent static force calculation methods for transient impact force of a vehicle in collision with piers

    Institute of Scientific and Technical Information of China (English)

    崔鹏; 夏禾; 夏超逸; 吴萱

    2014-01-01

    随着公路、铁路、城市立交桥的大量建设,跨线桥数量剧增,桥墩被汽车撞击的可能性大大增加。建立卡车撞击桥墩精细有限元分析模型,采用LS-DYNA碰撞分析软件计算分析了Ford卡车以不同速度撞击桥墩的撞击力特性。采用全局平均法、局部平均法、等效位移法、简化脉冲荷载法4种计算汽车撞击力等效静力方法,计算了撞击过程的等效静力值,并与美国《AASHTO》规范、中国《铁路桥涵设计基本规范》和《公路桥涵设计通用规范》中给出的汽车等效静力限值进行了比较,指出了各种计算方法的适应范围和精确度,可供工程设计参考。%Due to quick development of elevated overpass bridges of highways,railways and urban overpass nowadays,the probability of vehicle colliding with piers increases sharply.An analysis model for a truck-pier system was set up using the finite element software ANSYS LS_DYNA to analyze the impact force characteristics of the truck at different speeds.Here,four calculation methods for equivalent static force of truck-pier collision force were presented including the global average method,the local average method,the equivalent displacement method,and the simplified pulse load method.Using these methods,the equivalent static forces were calculated,and the results were compared with the allowances given in AASHTO-LRFD,Chinese Railway Code and Chinese Highway Code.Based on comparisons,the adaptive scope and the accuracy of the four methods were pointed out,a reference was provided for engineering design.

  12. Hydrographic surveys of the Missouri and Yellowstone Rivers at selected bridges and through Bismarck, North Dakota, during the 2011 flood

    Science.gov (United States)

    Densmore, Brenda K.; Strauch, Kellan R.; Dietsch, Benjamin J.

    2013-01-01

    The U.S. Geological Survey (USGS), in cooperation with the North Dakota Department of Transportation and the North Dakota State Water Commission, completed hydrographic surveys at six Missouri River bridges and one Yellowstone River bridge during the 2011 flood of the Missouri River system. Bridges surveyed are located near the cities of Cartwright, Buford, Williston, Washburn, and Bismarck, N. Dak. The river in the vicinity of the bridges and the channel through the city of Bismarck, N. Dak., were surveyed. The hydrographic surveys were conducted using a high-resolution multibeam echosounder (MBES), the RESON SeaBatTM 7125, during June 6–9 and June 28–July 9, 2011. The surveyed area at each bridge site extended 820 feet upstream from the bridge to 820 feet downstream from the bridge. The surveyed reach through Bismarck consisted of 18 miles of the main channel wherever depth was sufficient. Results from these emergency surveys aided the North Dakota Department of Transportation in evaluating the structural integrity of the bridges during high-flow conditions. In addition, the sustained high flows made feasible the surveying of a large section of the normally shallow channel with the MBES. In general, results from sequential bridge surveys showed that as discharge increased between the first and second surveys at a given site, there was a general trend of channel scour. Locally, complex responses of scour in some areas and deposition in other areas of the channel were identified. Similarly, scour around bridge piers also showed complex responses to the increase in flow between the two surveys. Results for the survey area of the river channel through Bismarck show that, in general, scour occurred around river structures or where the river has tight bends and channel narrowing. The data collected during the surveys are provided electronically in two different file formats: comma delimited text and CARIS Spatial ArchiveTM (CSARTM) format.

  13. Seismic Isolation of Curved Continuous Bridge with Double Spherical Aseismic Bearing%双曲面球型减隔震支座曲线连续梁桥的减隔震

    Institute of Scientific and Technical Information of China (English)

    顾正伟; 钟铁毅; 张贞阁

    2011-01-01

    针对某3跨门式桥墩轨道交通曲线连续梁桥,采用其桥址提供的3条地震动时程曲线,应用SAP2000有限元软件,分析未隔震和双曲面球型减隔震支座隔震条件下的罕遇地震响应,进行双曲面球型减隔震支座曲线连续梁桥的减隔震研究.研究结果表明,曲线连续梁桥各桥墩的内力响应受响应内力方向与地震动输入方向火角的影响;仅固定墩切向隔震时,固定墩的切向内力大幅减少,弯矩和剪力分别减小约70%和50%,但各墩的径向内力均有增加,最大增幅约达10%,不能满足桥梁的抗震要求;固定墩切向和径向双向、滑动墩径向隔震时,固定墩的切向和径向内力均大幅减少,弯矩和剪力分别降低约73%和49%,同时各滑动墩的径向内力也大幅降低40%~60%,减震效果明显.%The FEA model of a 3-span rail transit curved continuous bridge with twin-legged portal pier is established by SAP2000. By using three earthquake time history waves provided by Seismic Safety Evaluation Report, the calculation of isolation and non-isolation seismic responses of curved continuous bridge with and without double spherical aseismic bearing under rarely-occurred earthquake is carried out. By comparison, the results show that the internal force responses of each pier of the curved continuous bridge are influenced by the angle between the response internal force direction and the earthquake input direction. When using double spherical aseismic bearing on braking pier in tangential direction, the seismic responses of the bending moment and the shearing force of braking pier in tangential direction decrease about 70% and 50% respectively while the seismic response of each pier in radial direction increases to a maximum of 10%, which can't meet the seismic requirements of the bridge. When putting double spherical aseismic bearing on braking pier both in tangential and radial direction and on sliding pier in radial direction, the

  14. NLP-PIER: A Scalable Natural Language Processing, Indexing, and Searching Architecture for Clinical Notes.

    Science.gov (United States)

    McEwan, Reed; Melton, Genevieve B; Knoll, Benjamin C; Wang, Yan; Hultman, Gretchen; Dale, Justin L; Meyer, Tim; Pakhomov, Serguei V

    2016-01-01

    Many design considerations must be addressed in order to provide researchers with full text and semantic search of unstructured healthcare data such as clinical notes and reports. Institutions looking at providing this functionality must also address the big data aspects of their unstructured corpora. Because these systems are complex and demand a non-trivial investment, there is an incentive to make the system capable of servicing future needs as well, further complicating the design. We present architectural best practices as lessons learned in the design and implementation NLP-PIER (Patient Information Extraction for Research), a scalable, extensible, and secure system for processing, indexing, and searching clinical notes at the University of Minnesota. PMID:27570663

  15. Alexia Gassin & John Pier (eds), L’effacement selon Nabokov : Lolita

    OpenAIRE

    Suzanne FRAYSSE

    2015-01-01

    Ce livre publié par Alexia Gassin et John Pier rassemble les communications d’une journée d’études organisée en février 2010 par Chloé Deroy et Philippe Chardin à Tours dans le cadre d’une collaboration entre anglicistes et comparatistes. Il vise à analyser les affinités et divergences thématiques, structurelles et éditoriales entre deux romans de Nabokov : The Original of Laura, une œuvre inachevée publiée pour la première fois en 2009 par Dmitri Nabokov contre la volonté de son père, et Lol...

  16. NLP-PIER: A Scalable Natural Language Processing, Indexing, and Searching Architecture for Clinical Notes

    Science.gov (United States)

    McEwan, Reed; Melton, Genevieve B.; Knoll, Benjamin C.; Wang, Yan; Hultman, Gretchen; Dale, Justin L.; Meyer, Tim; Pakhomov, Serguei V.

    2016-01-01

    Many design considerations must be addressed in order to provide researchers with full text and semantic search of unstructured healthcare data such as clinical notes and reports. Institutions looking at providing this functionality must also address the big data aspects of their unstructured corpora. Because these systems are complex and demand a non-trivial investment, there is an incentive to make the system capable of servicing future needs as well, further complicating the design. We present architectural best practices as lessons learned in the design and implementation NLP-PIER (Patient Information Extraction for Research), a scalable, extensible, and secure system for processing, indexing, and searching clinical notes at the University of Minnesota. PMID:27570663

  17. Bridge technology report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. As LANs have proliferated, new technologies and system concepts have come to the fore. One of the key issues is how to interconnect networks. One means of interconnection is to use a 'bridge'. Other competing technologies are repeaters, routers, and gateways. Bridges permit traffic isolation, connect network segments together and operate at the MAC layer. Further, because they operate at the MAC layer, they can handle a variety of protocols such as TCP/IP, SNA, and X.25. This report focuses on the specific technology of bridging two netw

  18. Bridged Race Population Estimates

    Data.gov (United States)

    U.S. Department of Health & Human Services — Population estimates from "bridging" the 31 race categories used in Census 2000, as specified in the 1997 Office of Management and Budget (OMB) race and ethnicity...

  19. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    The first Scandinavian bridge with a span of more than 500 m was the Lillebælt Suspension Bridge opened to traffic in 1970.Art the end of the 20th century the longest span of any European bridge is found in the Storebælt East Bridge with a main span of 1624 m. Also the third longest span in Europ...

  20. 大跨度连续梁拱组合桥梁轨互制特征%Track-bridge Interaction of Combination Bridge with Long-span Continuous Beam Arch

    Institute of Scientific and Technical Information of China (English)

    王伟民

    2016-01-01

    To study the characteristics of track-beam interaction of the combination bridge with long-span continuous beam arch, a rigid frame arch combination bridge with (34+160+34) m continuous steel-box girder tied-arch on Meizhou-Chaoshan railway line is referenced. A track-arch-beam-pier integration space model is established to simulate track longitudinal resistance with ideal elastic-plastic model. The distribution of track longitudinal force is analyzed. The girder stress, the rotation angle at bridge end, and the longitudinal reaction at pier bottom are compared with or without track effects. Results show that rail longitudinal force is great at the beam end farther away from the fixed support of the combination bridge with continuous beam arch; the maximum expansion stress reaches to 114. 0 MPa, but the rail strength meets the requirements without rail expansion devices;the track structure has great impact on the stress of girder under the action of temperature load or braking force and it also has great impact on rotation angle at bridge end and on the distribution of longitudinal reaction at pier bottom.%为研究大跨度连续梁拱组合桥梁轨相互作用特征,以梅汕线上某(34+160+34) m刚架系杆拱钢箱连续梁组合桥为背景,采用理想弹塑性模型模拟线路纵向阻力,建立“轨拱梁墩”一体化空间模型,对钢轨纵向力的分布规律进行分析,对是否考虑轨道作用下的主梁应力、梁端转角、墩底纵向反力进行比较。结果表明:连续梁拱组合桥远离固定支座的梁端处钢轨纵向力较大,其中最大伸缩应力达到114.0 MPa,在不设钢轨伸缩调节器时钢轨强度仍满足要求;轨道结构对温度荷载和制动力作用下的主梁应力影响较大;轨道结构对梁端转角及墩底纵向反力的分配亦有较大影响。

  1. Docks and Piers, Port of Green Bay docks along the Fox River are complete, Published in 2008, 1:1200 (1in=100ft) scale, Brown County, WI.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Docks and Piers dataset, published at 1:1200 (1in=100ft) scale, was produced all or in part from Orthoimagery information as of 2008. It is described as 'Port...

  2. An Automatic Method for Geometric Segmentation of Masonry Arch Bridges for Structural Engineering Purposes

    Science.gov (United States)

    Riveiro, B.; DeJong, M.; Conde, B.

    2016-06-01

    Despite the tremendous advantages of the laser scanning technology for the geometric characterization of built constructions, there are important limitations preventing more widespread implementation in the structural engineering domain. Even though the technology provides extensive and accurate information to perform structural assessment and health monitoring, many people are resistant to the technology due to the processing times involved. Thus, new methods that can automatically process LiDAR data and subsequently provide an automatic and organized interpretation are required. This paper presents a new method for fully automated point cloud segmentation of masonry arch bridges. The method efficiently creates segmented, spatially related and organized point clouds, which each contain the relevant geometric data for a particular component (pier, arch, spandrel wall, etc.) of the structure. The segmentation procedure comprises a heuristic approach for the separation of different vertical walls, and later image processing tools adapted to voxel structures allows the efficient segmentation of the main structural elements of the bridge. The proposed methodology provides the essential processed data required for structural assessment of masonry arch bridges based on geometric anomalies. The method is validated using a representative sample of masonry arch bridges in Spain.

  3. A Multimode Adaptive Pushover Procedure for Seismic Assessment of Integral Bridges

    Directory of Open Access Journals (Sweden)

    Ehsan Mohtashami

    2013-01-01

    Full Text Available This paper presents a new adaptive pushover procedure to account for the effect of higher modes in order to accurately estimate the seismic response of bridges. The effect of higher modes is considered by introducing a minimum value for the total effective modal mass. The proposed method employs enough number of modes to ensure that the defined total effective modal mass participates in all increments of the pushover loading. An adaptive demand curve is also developed for assessment of the seismic demand. The efficiency and robustness of the proposed method are demonstrated by conducting a parametric study. The analysis includes 18 four-span integral bridges with various heights of piers. The inelastic response history analysis is employed as reference solution in this study. Numerical results indicate excellent accuracy of the proposed method in assessment of the seismic response. For most bridges investigated in this study, the difference between the estimated response of the proposed method and the inelastic response history analysis is less than 25% for displacements and 10% for internal forces. This indicates a very good accuracy compared to available pushover procedures in the literature. The proposed method is therefore recommended to be applied to the seismic performance evaluation of integral bridges for engineering applications.

  4. Analysis of Seismic Response of Main Bridge of Yili River Bridge%新疆伊犁河大桥主桥地震响应分析

    Institute of Scientific and Technical Information of China (English)

    刘坤

    2012-01-01

    研究目的:新疆伊犁河大桥是连接218国道和313省道的重点控制工程,主桥为(66+5×120+66)m 双肢薄壁连续刚构桥,该桥被称为新疆第一大桥.桥址位于7度地震区内,目前对这类大跨度连续刚构桥的地震反应研究很少.为保证该桥的抗震安全,研究该桥的地震响应规律,为同类桥梁设计提供参考依据.研究结论:通过分析得出:(1)对于连续刚构桥而言,塑性铰的位置出现在刚构墩的墩顶及墩底,抗震设计时需要加强此处的设计;(2)该大桥在地震反应下,虽然出现塑性铰,但与破坏位移还有一定的距离;(3)该桥具有一定的延性能力,满足大震不倒的要求.%Research purposes: The Yili River Bridge is an important project to connect the 218 National Highway with 313 Provincial Highway and is the largest bridge in Xingjiang with main bridge of coupled thin wall continuous rigid frame bridge(66 +5×120 +66) m. It is located in 7 degree earthquake region. As there is a little research on the seismic response of long span continuous rigid frame bridge is very rare , it is necessary to research the seismic response regulations of this bridge to make sure the bridge safety and provide the reference to the similar works. Research conclusions:From the analysis it is concluded (1) For the continuous rigid frame bridge, the plastic hinges region is on the top or bottom of frame pier and where need to be strengthened. (2) Under the seismic reaction, the plastic hinges happen to this bridge, but they keep certain away from the damaged displacement. (3) The Yili River Bridge has enough ductility and it can not fall under the serious earthquake.

  5. Integral Abutment and Jointless Bridges

    OpenAIRE

    Cristian-Claudiu Comisu

    2005-01-01

    Integral bridges, or integral abutment and jointless bridges, as they are more commonly known in the USA, are constructed without any movement joints between spans or between spans and abutments. Typically these bridges have stub-type abutments supported on piles and continuous bridge deck from one embankment to the other. Foundations are usually designed to be small and flexible to facilitate horizontal movement or rocking of the support. Integrally bridges are simple or multiple span ones t...

  6. Networked collaborative pseudo-dynamic testing of a multi-span bridge based on NetSLab

    Institute of Scientific and Technical Information of China (English)

    Cai Xinjiang; Tian Shizhu; Wang Dapeng; Xiao Yan

    2009-01-01

    Modem dynamic tests such as networked collaborative pseudo-dynamic testing (PDT) provide new tools to study the dynamic performance of large and complex structures. In this paper, several networked collaborative PDT systems established in China and abroad are introduced, including a detailed description of the first networked collaborative platform that involved the construction of a standardized demonstration procedure for networked collaborative PDT. The example is a multi-span bridge with RC piers retrofitted by FRP, and a networked structural laboratory (NetSLab) platform is used to link distributed laboratories located at several universities together. Substructure technology is also used in the testing. The characteristics, resource sharing and collaborative work of NetSLab are described, and the results illustrate that use of the NetSLab is feasible for studying the dynamic performance of multi-span bridge structures.

  7. Estimation of potential scour at bridges on local government roads in South Dakota, 2009-12

    Science.gov (United States)

    Thompson, Ryan F.; Wattier, Chelsea M.; Liggett, Richard R.; Truax, Ryan A.

    2014-01-01

    In 2009, the U.S. Geological Survey and South Dakota Department of Transportation (SDDOT) began a study to estimate potential scour at selected bridges on local government (county, township, and municipal) roads in South Dakota. A rapid scour-estimation method (level-1.5) and a more detailed method (level-2) were used to develop estimates of contraction, abutment, and pier scour. Data from 41 level-2 analyses completed for this study were combined with data from level-2 analyses completed in previous studies to develop new South Dakota-specific regression equations: four regional equations for main-channel velocity at the bridge contraction to account for the widely varying stream conditions within South Dakota, and one equation for head change. Velocity data from streamgages also were used in the regression for average velocity through the bridge contraction. Using these new regression equations, scour analyses were completed using the level-1.5 method on 361 bridges on local government roads. Typically, level-1.5 analyses are completed at flows estimated to have annual exceedance probabilities of 1 percent (100-year flood) and 0.2 percent (500-year flood); however, at some sites the bridge would not pass these flows. A level-1.5 analysis was then completed at the flow expected to produce the maximum scour. Data presented for level-1.5 scour analyses at the 361 bridges include contraction, abutment, and pier scour. Estimates of potential contraction scour ranged from 0 to 32.5 feet for the various flows evaluated. Estimated potential abutment scour ranged from 0 to 40.9 feet for left abutments, and from 0 to 37.7 feet for right abutments. Pier scour values ranged from 2.7 to 31.6 feet. The scour depth estimates provided in this report can be used by the SDDOT to compare with foundation depths at each bridge to determine if abutments or piers are at risk of being undermined by scour at the flows evaluated. Replicate analyses were completed at 24 of the 361 bridges

  8. 新型高速铁路专用桥梁检测车的设计方案%Design scheme of bridge-inspection vehicle applies for new high-speed railway bridge

    Institute of Scientific and Technical Information of China (English)

    张效奎; 刘伟; 韩国梁; 李娟娟

    2012-01-01

    In order to solve the problems of new high-speed railway bridge cancel human pavement,the skylight time limit and other characteristics that traditional bridge test equipment maintenance can't reach the detection requirements,a mechanical design plan of new high-speed railway bridge-detection vehicle was investigated. This bridge-detection vehicle uses the structure of fixed gate-type girder,its guiding girder and drive girder walk alternately. This vehicle can detect the onderkant of the bridge and bridge piers with image acquisition technology and can pass the bridge pier automatically without affect the normal train traffic. And its 3D modeling and simulation animation was completed by Solidworks.the virtual prototype was tested. The experimental results show that this design scheme is feasible. This plan will provide reference to more testing and maintenance of railway bridge equipment research and development.%为了解决新型高速铁路桥梁取消人行便道、受“天窗”时间限制等传统桥梁检测维护设备不能达到检测要求的问题,提出了一种新型高速铁路专用桥梁检测车的机械设计方案.该检测车设计采用门式梁固联、导向梁和驱动梁交替行走结构形式;利用图像采集技术实施对高铁桥梁下表面及桥墩的检测;可在不影响列车正常通行的情况下,实现自动过墩.最后,用Solidworks完成了三维建模及动画仿真,并进行了虚拟样机试验.研究结果表明,该设计方案是可行的,为更多高速铁路桥梁检测维护设备研发提供了借鉴和参考.

  9. 既有铁路混凝土简支梁桥加固技术研究%Research on Reinforcing Technology for Existing Railway Concrete Simplysupported Beam Bridge

    Institute of Scientific and Technical Information of China (English)

    侯勇; 侯刚

    2011-01-01

    Research purposes: The existing railway concrete simply - supported beam bridge is mainly of medium and small span style. The theory and practice showed after the train speed - raise, the lateral stiffness of the most beam was not enough and the pier stiffness was not enough because the pier section was small. They could not meet the speed -raise requirement, so it was necessary to reinforce the beam and pier. For the upgrading plan of the Luohe - Fuyang Railway, the study was done on the reinforcing technology for the existing railway concrete simply - supported beam bridge and the the experience of it was summed up for offering the reference to the similar works. Research conclusions: Strengthening the transverse connection of the diaphragm of the concrete simple - supported beam can well control the lateral vibration of the bridge. Adding the beam bonding steel plates and the external prestressing steel strands can effectively increase the load - bearing capacity of the beam. Enlarging the cross section of the pier can greatly enhance the lateral rigidity of the piers. The existing railway concrete simply - supported beam bridge reinforced by taking the above measures can meet the speed - raise requirements.%研究目的:既有铁路混凝土梁桥以中小跨度为主,理论与实践表明列车提速后,大多数梁体横向刚度不足,墩台截面偏小同样会刚度不够,不能满足提速的要求,为此需要对梁体及墩台进行加固改造.本文结合漯阜铁路既有线提速及改建设计,对既有铁路混凝土简支梁桥加固进行研究,总结了一些经验,有益于其它既有线铁路桥梁加固参考.研究结论:加强混凝土简支梁横隔板横向连接,可很好地抑制桥梁横向振动;梁底粘贴钢板、增设体外预应力钢束,可有效提高梁的承载能力;加大桥墩截面可大幅度增加横向刚度;采取以上措施加固的既有铁路混凝土简支梁桥能满足提速要求.

  10. Istanbul Bridge Conference 2014

    CERN Document Server

    Gülkan, Polat; Mahmoud, Khaled

    2016-01-01

      The book includes peer-reviewed contributions selected from presentations given at the Istanbul Bridge Conference 2014, held from August 11 – 13 in Istanbul, Turkey. It reports on the current challenges in bridge engineering faced by professionals around the globe, giving a special emphasis to recently developed techniques, innovations and opportunities. The book covers key topics in the field, including modeling and analysis methods; construction and erection techniques; design for extreme events and condition assessment and structural health monitoring. There is a balanced presentation of theory, research and practice. This book, which provides the readers with a comprehensive and timely reference guide on current practices in bridge engineering, is intended for professionals, academic researchers and students alike.

  11. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  12. Soil-structure interaction modeling effects on seismic response of cable-stayed bridge tower

    Science.gov (United States)

    Raheem, Shehata E. Abdel; Hayashikawa, Toshiro

    2013-12-01

    A nonlinear dynamic analysis, including soil-structure interaction, is developed to estimate the seismic response characteristics and to predict the earthquake response of cable-stayed bridge towers with spread foundation. An incremental iterative finite element technique is adopted for a more realistic dynamic analysis of nonlinear soil-foundation-superstructure interaction system under great-earthquake ground motion. Two different approaches to model soil foundation interaction are considered: nonlinear Winkler soil foundation model and linear lumped-parameter soil model. The numerical results show that the simplified lumped-parameter-model analysis provides a good prediction for the peak response, but it overestimates the acceleration response and underestimates the uplift force at the anchor between superstructure and pier. The soil bearing stress beneath the footing base is dramatically increased due to footing base uplift. The predominant contribution to the vertical response at footing base resulted from the massive foundation rocking rather than from the vertical excitation.

  13. Quantum Bidding in Bridge

    Science.gov (United States)

    Muhammad, Sadiq; Tavakoli, Armin; Kurant, Maciej; Pawłowski, Marcin; Żukowski, Marek; Bourennane, Mohamed

    2014-04-01

    Quantum methods allow us to reduce communication complexity of some computational tasks, with several separated partners, beyond classical constraints. Nevertheless, experimental demonstrations of this have thus far been limited to some abstract problems, far away from real-life tasks. We show here, and demonstrate experimentally, that the power of reduction of communication complexity can be harnessed to gain an advantage in a famous, immensely popular, card game—bridge. The essence of a winning strategy in bridge is efficient communication between the partners. The rules of the game allow only a specific form of communication, of very low complexity (effectively, one has strong limitations on the number of exchanged bits). Surprisingly, our quantum technique does not violate the existing rules of the game (as there is no increase in information flow). We show that our quantum bridge auction corresponds to a biased nonlocal Clauser-Horne-Shimony-Holt game, which is equivalent to a 2→1 quantum random access code. Thus, our experiment is also a realization of such protocols. However, this correspondence is not complete, which enables the bridge players to have efficient strategies regardless of the quality of their detectors.

  14. Bridge of Light

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Lying gleaming white under a brooding sky,the Lhasa River Railway Bridge forms a gate to Lhasa City.Built as a part of Qinghai-Tibet Railway,on July 1,2011, the highest altitude railway in the world has been in service for five years. Lhasa,Tibet

  15. Bridge over troubled water?

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Nannestad, Peter; Svendsen, Gert Tinggaard

    2008-01-01

    The problem of integrating non-Western immigrants into Western welfare states is the focus of this paper. To address this issue, we suggest a social capital approach in which we apply the conceptual pair of bridging social capital (BR), which connects an individual to the broader social structure...

  16. Building Bridges to China.

    Science.gov (United States)

    Wasta, Stephanie; Scott, Margaret

    1998-01-01

    Describes a theme cycle called "Building Bridges to China" developed for third grade students that focuses on the similarities between the lives of children and families in China and the United States. Explains that the theme cycle addresses the National Geography Standards and three of the National Council for the Social Studies standards. (CMK)

  17. Design of Gutianxi Bridge on Hefei-Fuzhou Railway%合福铁路古田溪特大桥设计

    Institute of Scientific and Technical Information of China (English)

    李浩勇

    2012-01-01

    古田溪特大桥是新建合福铁路重点控制桥梁工程之一,该桥集高墩大跨、深水基础于一身,兼具山区铁路与高速铁路双重特点,设计施工难度大。研究其桥式方案选择及设计施工要点,通过分析无缝线路特性,合理确定主桥桥式方案;结合施工组织,总结了主跨梁部结构、主桥桥墩及主墩基础的设计施工要点。车桥耦合动力仿真分析结论表明,当车速不超过该桥设计车速350 km/h时,安全性指标均在限值以内。%Gutianxi Bridge is one of the controlling bridges for the newly-built Hefei-Fuzhou Railway.It’s characterized as high pier,long span,and deep under-water foundation,with a total length of 588.89 m,highest pier of 49.5 m and under water foundation of 42.4 m.This bridge serves as both mountain railway as well as high speed railway,which has presented great challenges in both design and construction.Through research & study on the selection of the bridge type and the critical points of design & construction,experiences have been accumulated in the design of deep water foundation for high speed railway in mountainous areas.The bridge type of main span has been reasonably determined via analysis on characteristics of seamless rails.The critical points of design & construction for the beam structure,the pier & the foundation of the main span are summarized,in combination with the organization of construction.The dynamic simulation analysis on the interaction between the bridge and the vehicle demonstrates that when the operation speed is not higher than the design speed of 350 km/h,the safety indexes are within limits and the comfort indexes are above the "sound" level,which further proves that the design safety and comfort index are suitable.

  18. Revised Rules for Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Jensen, F. M.; Middleton, C.;

    This paper is based on research performed for the Highway Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: Concrete Bridges" It contains details of a methodology which can be used to generate Whole Life (WL) reliability profiles....... These WL reliability profiles may be used to establish revised rules for Concrete Bridges....

  19. Application of Fluid Viscous Dampers in the Bridge Seismic%液体粘滞阻尼器在梁桥抗震中的应用

    Institute of Scientific and Technical Information of China (English)

    卢旭阳; 刘力

    2015-01-01

    To a main road bridge three spans prestressed concrete cantilever beam as the engineering background,using the finite ele-ment software Midas/civil space finite element model is established.Set is obtained by using the nonlinear time history analysis method before and after the viscous dampers along the bridge to the node displacement and the change of the pier bottom bending and pier top shear force,so as to evaluate viscous dampers to improve seismic performance of bridges.The results show that the reasonable setting of fluid viscous damper can effectively reduce the bridge displacement and shear force loaded on top,to improve the seismic perform-ance of the bridge.%以某公路桥主桥三跨预应力混凝土悬臂梁为工程背景,利用有限元软件 Midas/civil 建立空间有限元模型。采用非线性时程分析方法计算设置粘滞阻尼器前后顺桥向节点位移、墩底弯矩、墩顶剪力的变化,从而评价粘滞阻尼器对提升桥梁抗震性能的作用。结果表明,合理设置液体粘滞阻尼器可以有效地减小桥梁位移和墩顶剪力,改善桥梁的抗震性能。

  20. Dynamic Bridge Response for a Bridge-friendly Truck

    Directory of Open Access Journals (Sweden)

    V. Šmilauer

    2004-01-01

    Full Text Available A truck with controlled semi-active suspensions traversing a bridge is examined for benefits to the bridge structure. The original concept of a road-friendly truck was extended to a bridge-friendly vehicle, using the same optimization tools. A half-car model with two independently driven axles is coupled with simply supported bridges (beam, slab model with the span range from 5 m to 50 m. Surface profile of the bridge deck is either stochastic or in the shape of a bump or a pot in the mid-span. Numerical integration in the MATLAB/SIMULINK environment solves coupled dynamic equations of motion with optimized truck suspensions. The rear axle generates the prevailing load and to a great extent determines the bridge response. A significant decrease in contact road-tire forces is observed and the mid-span bridge deflections are on average smaller, when compared to commercial passive suspensions. 

  1. 桥梁建设与河道行洪纳潮的适应性分析%Analysis of adaptability for bridge construction and river channel for coursing flood and tide

    Institute of Scientific and Technical Information of China (English)

    徐林春; 赵明登; 张庭荣; 何书琴

    2012-01-01

    Taking a grand bridge engineering for example,the method of combination of one-dimensional river network mathematical model and local river 2-D tidal flow mathematical model is used to calculate and analyze the influence of the bridge on river coursing flood and tide.The problem of adaptability for bridge construction and river coursing flood and tide is discussed from layout of axis,elevation of beam at the bridge bottom,form of pier and cushion cap,combination of the bridge span,degree of water resistance,relation between the pier of the bridge and the dike,etc.Some general suggestions about the arrangement of the bridge pier and cushion cap are proposed to make the bridge construction to adapt the ability of the river flood and tide as far as possible;and the suggestions can be provided to the department of water administration as a reference for administrative licensing.%以某特大桥为例,采用大范围一维网河数学模型与工程局部河道平面二维潮流数学模型相结合的方法,对该特大桥的行洪、纳潮影响进行了计算和分析.从大桥工程的轴线布置、梁底标高、墩台形式、桥跨组合、阻水程度、建设项目与堤防关系等方面论述了跨河桥梁建设与河道行洪、纳潮之间的适应性问题.为减少桥梁建设对河道行洪、纳潮的影响,从桥梁墩台布置等方面提出了指导性建议,使桥梁建设尽可能与河道行洪、纳潮能力相适应,也为水行政主管部门的行政许可提供参考.

  2. [Retention of adhesive bridges].

    Science.gov (United States)

    Raes, F; De Boever, J

    1994-04-01

    Since the development of adhesive bridges in the early seventies, the retention and therefore the durability of these bridges has been tremendously improved. Conditioning of the non-precious metal by silanisation, careful acid etching of the enamel and the use of the appropriate composite resin are of prime importance. Furthermore, the meticulous preparation with enough interproximal embrace, occlusal rests, interocclusal clearance and cingulum stops is equally important. Including more teeth in the design does not necessarily lead to an improved retention. Besides the material and technical aspects, the whole clinical procedure needs much attention. The retention does not depend on one single factor, but on the precision of all the necessary clinical steps and on a well-defined selection of the material. In this way a five-year survival rate of close to 80% can be obtained. PMID:11830965

  3. BRIDGING SERVICE QUALITY GAPS

    OpenAIRE

    BARKATH UNISSA

    2012-01-01

    Bridging the Service quality gaps is one of the foremost areas of concern for amarketer. Service marketing is inherently different from product or goods marketing.Services are distinctively characterized by their intangible, heterogeneous, inseparableand perishable nature. The importance of the service sector in today's world is a verywidely accepted and renowned idea. “We are already experiencing a service society“services do have some basic characteristics which make them fundamentally diff...

  4. Bridging as Coercive Accommodation

    CERN Document Server

    Bos, J W; Mineur, A M; Bos, Johan; Buitelaar, Paul; Mineur, Anne-Marie

    1995-01-01

    In this paper we discuss the notion of "bridging" in Discourse Representation Theory as a tool to account for discourse referents that have only been established implicitly, through the lexical semantics of other referents. In doing so, we use ideas from Generative Lexicon theory, to introduce antecedents for anaphoric expressions that cannot be "linked" to a proper antecedent, but that do not need to be "accommodated" because they have some connection to the network of discourse referents that is already established.

  5. Nematic liquid crystal bridges

    Science.gov (United States)

    Doss, Susannah; Ellis, Perry; Vallamkondu, Jayalakshmi; Danemiller, Edward; Vernon, Mark; Fernandez-Nieves, Alberto

    We study the effects of confining a nematic liquid crystal between two parallel glass plates with homeotropic boundary conditions for the director at all bounding surfaces. We find that the free surface of the nematic bridge is a surface of constant mean curvature. In addition, by changing the distance between the plates and the contact angle with the glass plates, we transition between loops and hedgehogs that can be either radial or hyperbolic.

  6. Environmental life cycle assessment comparison between two bridge types: reinforced concrete bridge and steel composite bridge

    DEFF Research Database (Denmark)

    Du, Guangli; Karoumi, Raid

    2013-01-01

    not been integrated into the decision-making process. This paper presents a systematic LCA method for quantifying the environmental impacts for bridges. The comparison study is performed between a reinforced concrete bridge and a steel bridge as an alternative design, with several key maintenance and EOL......The concept of sustainable construction has attracted an increased attention. Bridge infrastructures and their belonged construction activities consume considerable material and energy, which is responsible for large environmental burdens. However, the environmental assessment of bridges has...

  7. Metal and PAH concentrations in fruit of Vaccinium angustifolium Ait. (Lowbush Blueberry) : a comparison among Whitney Pier, North Sydney and supermarket

    Energy Technology Data Exchange (ETDEWEB)

    Hale, B. [Guelph Univ., ON (Canada). Dept. of Land Resource Science

    2004-07-01

    The concentration of various metals in the fruit harvested from Lowbush blueberry plants in Whitney Pier, Sydney, Nova Scotia (NS), North Sydney (NS) and supermarket were quantified in this report. The concentrations were compared among the 3 sources to determine whether the metal and Polycyclic Aromatic Hydrocarbons (PAHs) concentrations in the blueberries from Whitney Pier were higher or lower compared to the reference blueberries from North Sydney and the supermarket. Mean values for each of the analytes were compared using analysis of variance (ANOVA). The study determined whether washed berries have lower concentrations of contaminants than unwashed berries. The risk to human health of exposure to metals and PAHs through consumption of blueberry samples was also calculated. It was concluded that concentrations of selenium and zinc are elevated in blueberries from Whitney Pier compared to berries from North Sydney and the supermarket, but are well within safe levels. Other elements such as arsenic, titanium, vanadium, lead, copper and molybdenum were similar, and only thallium was elevated in supermarket berries relative to those from Whitney Pier and North Sydney. Chromium was not detected in any samples. It was determined that there was no risk to human health from exposure to any of the metals analyzed, regardless of whether they were Whitney Pier samples or reference samples. Only 2 PAHs were detected in one of the unwashed samples from Whitney Pier. No PAHs were found in washed berries or unwashed berries from the supermarket or North Sydney. It was concluded that there was no risk to human health from exposure to any of the PAHs. Washed and unwashed samples had similar metal concentrations, indicating that surface contamination did not occur. A full methodology of the testing program was provided. 11 refs., 7 tabs., 2 figs.

  8. A comparative study between China and U.S. on seismic design philosophy and practice of a long span arch bridge

    Institute of Scientific and Technical Information of China (English)

    Xu Yan; George C Lee; Fan Lichu; Hu Shide

    2006-01-01

    This paper presents the first of a series of case studies on the seismic design of long span bridges (cablestayed bridges, suspension bridges and arch bridges) under a cooperative research project on seismic behavior and design of highway bridges between the State Key Laboratory for Disaster Reduction in Civil Engineering, Tongji University and the Multidisciplinary Center for Earthquake Engineering Research, University at Buffalo. The objective of this series of case studies is to examine the differences and similarities on the seismic design practice of long span bridges in China and the U.S., to identify research needs and to develop design guidelines beneficial to bridge engineers in both countries. Unlike short to medium span bridges, long span bridges are not included in most seismic design specifications, mainly because they are location dependent and structurally unique. In this paper, an available model of a steel tied half through arch bridge with a main span of 550m in China is discussed. Analysis is focused on comparisons of the seismic responses due to different ground motions. Seismic design criteria and seismic performance requirements for long span bridges in both countries were first introduced and compared, and then three near field earthquake records with large vertical components were selected as the excitations to examine the seismic behavior and seismic vulnerability of the bridge. Results show that (1) the selected near field ground motions cause larger responses to key components (critical sections) of the bridge (such as arch rib ends) with a maximum increase of more than twice those caused by the site specific ground motions; (2) piers, longitudinal girders and arch crowns are more vulnerable to vertical motions, especially their axial forces; and (3) large vertical components of near field ground motions may not significantly affect the bridge's internal forces provided that their peak acceleration spectra ordinates only appear at periods

  9. Design of Main Bridge of Xi′nan Bridge in Guigang City,Guangxi%广西贵港西南大桥主桥设计

    Institute of Scientific and Technical Information of China (English)

    李翠霞; 张巨生

    2015-01-01

    广西贵港市西南大桥主桥为(46+88+280+88+46) m双塔双索面预应力混凝土边主梁斜拉桥。主梁采用等高度带悬臂的矩形混凝土边主梁与“工”字形钢横梁相结合的形式,整幅桥面宽36.5m,设双向2.0%横坡。桥塔采用“鱼”状流线弧形框架钢筋混凝土结构,塔柱高102.5 m,采用外侧为“D”形圆弧段的箱形截面。桥塔设上、下横梁,均采用预应力混凝土单箱单室结构。全桥共设136根斜拉索,斜拉索采用φs 15.2 m m镀锌钢绞线索,空间双索面扇形布置。桥塔墩采用分离式基础,上、下游分离式基础中心距34.7 m ,其下各设9根φ2.5 m钻孔桩。承台为正方形钢筋混凝土结构。4号墩顶面设一圆端形塔座。%The main bridge of the Xi′nan Bridge in Guigang City ,Guangxi is a prestressed concrete edge main girders cable‐stayed bridge with double pylons ,double cable planes and with span arrangement (46+88+280+88+46) m .T he main girders of the bridge are of the structural type combining the rectangular concrete edge main girders having constant depth and cantilevers with the I‐shape steel cross beams .The width of the whole bridge deck is 36 .5 m and the deck is provided with dual 2 .0% transverse slopes .A pylon of the bridge is the“fish”‐shape streamlined arc frame reinforced concrete structure that is 102 .5 m in height and the outer side of the pylon is of the“D”‐shape round arc box section .The upper and lower cross beams of the pylon are all the prestressed concrete single‐cell single‐box structures .There are totally 136 stay cables arranged for the whole bridge .The stay cables are the φs 15 .2 mm galvanized steel wire strand cables and are arranged in fan shape and spatial double cable planes .The pylon pier is supported on the sep‐arated foundations .T he center‐to‐center distance of the foundations on the upstream and dow n‐stream sides is 34 .7

  10. Vulnerability of bridges to fire

    DEFF Research Database (Denmark)

    Giuliani, Luisa; Crosti, C.; Gentili, F.

    2012-01-01

    Even if recent effort in developing methodology and measures for design structures against fire and explosions has been mostly focused on buildings, bridges can also be very sensitive to those actions, as witnesses by some recent bridge accidents, which caused major economic losses and also...... endangered people safety in few cases. Purpose of this paper is making a focus on the state of the art of the research and current regulations concerning the response of bridges to fire. Several cases of bridge fires are reported and a focus is made on the occurrence and consequence of bridge fires......, considering both the costs deriving by structural damages and by limited serviceability and other indirect societal aspects. Few cases of recent bridge fire are reviewed in detail and structural consequences are highlighted, distinguishing between damages directly induced by fire and damages induced by local...

  11. Theory of bridge aerodynamics

    CERN Document Server

    Strømmen, Einar

    2006-01-01

    This text book is intended for studies in wind engineering, with focus on the stochastic theory of wind induced dynamic response calculations for slender bridges or other line ?like civil engineering type of structures. It contains the background assumptions and hypothesis as well as the development of the computational theory that is necessary for the prediction of wind induced fluctuating displacements and cross sectional forces. The simple cases of static and quasi-static structural response calculations are for the sake of completeness also included. The text is at an advanced level in the

  12. Modelling railway bridge asset management

    OpenAIRE

    Le, Bryant Linh Hai

    2014-01-01

    The UK has a long history in the railway industry with a large number of railway assets. Railway bridges form one of the major asset groups with more than 35,000 bridges. The majority of the bridge population are old being constructed over 100 years ago. Many of the bridges were not designed to meet the current network demand. With an expected increasing rate of deterioration due to the increasing traffic loads and intensities, the management authorities are faced with the difficult task of k...

  13. Influence of piers on functional groups of benthic primary producers and consumers in the channel of a subtropical coastal lagoon

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Pagliosa

    2012-03-01

    Full Text Available Artificial habitats have become common in coastal areas worldwide and may influence the structure and functioning of benthic ecosystems. We analyze the influence of piers on the benthic morphofunctional groups of rocky seaweeds and of soft bottom macrofauna in the channel of Conceição Lagoon (southern Brazil. The main impact is a reduction in the luminosity available for photosynthetic activity which is directly related to a decrease in the biomasses of sediment microphytobenthos and of more highly structured macroalgae life-forms. Contrary to expectations, the morphotypes of potentially high biomass productivity, such as articulated coralline, corticated and leathery macroalgae, were in general less abundant and the low biomass foliose and filamentous macroalgae occurred in reference areas but not under the piers. The piers' effects on motile epifauna and infauna functional groups were site-specific and probably related to the general reduction in primary producer organisms in the new habitats. The discretely motile infauna was the only functional group able to thrive under the piers due to their reduced motility and fragile morphological structures, being benefited by the shelter provided by the artificial habitats. Our results showed that the piers might have a negative effect on the base-trophic level organisms responsible for bottom-up controls.Hábitats artificiais têm se tornado comum em áreas costeiras no mundo todo, podendo influenciar a estrutura e funcionamento de ecossistemas bênticos. Nós analisamos a influência de trapiches nos grupos morfofuncionais bênticos de algas associadas a substrato consolidado e de macrofauna em substrato inconsolidado, no canal da Lagoa da Conceição (sul do Brasil. O principal impacto da presença de trapiches é a redução da irradiação disponível para atividade fotossintética, o que está diretamente relacionado com o decréscimo na biomassa microfitobentônica no sedimento e de macroalga

  14. Structural Design of Multi-Pylon Cable-Stayed Bridge with Corrugated Steel Webs for Chaoyang Bridge in Nanchang%南昌朝阳大桥波形钢腹板多塔斜拉桥结构设计

    Institute of Scientific and Technical Information of China (English)

    陈水生; 钟志斌; 桂水荣; 刘旭政; 钟汉清

    2014-01-01

    The PC composite box girder with corrugated steel webs is applicable to bridges with a variety of structural types ,which exhibits superior durability and economic features as com‐pared with the common concrete box girder .The cable‐stayed bridge with corrugated steel webs is regarded as the type of structure where composite box girder with corrugated steel webs is ingen‐iously used ,making better use of the properties of the two structures . The main navigational bridge of the Chaoyang Bridge in Nanchang is a (79+ 5 × 150+79) m continuous composite box girder cable‐stayed bridge with corrugated steel webs .The bridge has six pylons and the stay ca‐bles are arranged in single cable plane .In addition ,the bridge has two layers of decks ,on the up‐per deck ,dual eight vehicle lanes (four lanes each side) are arranged and pedestrian and non‐mo‐torized vehicle lanes are arranged on the lower deck .Based on the analysis and study undertaken , small side span‐to‐main span ratio was chosen .Due to the multiple pylons ,the load path from the intermediate pylons to the side pylons is long and the effect of ancillary piers in the side spans is minimal ,as a result ,no ancillary piers are installed .In the structural system ,the pylons and the main girder are fixed while the girder and piers are separated .The box girder is 43 .84 m wide , with transverse steel diaphragms .The stay cables are fanned out in single cable plane .The pylon looks like the Chinese character“合“ ,and double bearings are installed at the pylons .T he stay vi‐bration mitigation bearings are used as the vibration mitigation and isolation devices of the super‐structure ,which are installed below the two side pylons .%波形钢腹板PC组合箱梁适用于不同结构形式的桥梁,相比普通混凝土箱梁具有显著的耐久性和经济性,波形钢腹板斜拉桥将波形钢腹板组合箱梁应用到斜拉桥中,充分发挥了2种结构的特点。南昌朝

  15. General Construction Scheme for Anqing Changjiang River Railway Bridge%安庆长江铁路大桥总体施工方案

    Institute of Scientific and Technical Information of China (English)

    农代培; 季跃华; 徐炳法

    2013-01-01

    安庆长江铁路大桥采用双塔三索面钢桁梁斜拉桥和6孔64 m跨现浇简支箱梁布置形式,铁路4线.深水区3号、4号桥塔墩采用先围堰后平台的双壁钢围堰施工方案;5号墩桩基采用定位桩平台施工方案,承台采用双壁钢围堰施工方案.浅水区6号、7号及W01号、W02号桥墩桩基采用双栈桥加定位桩平台施工方案,承台采用钢板桩围堰施工方案.桥塔起始段采用支架法施工,其余采用大节段液压爬模施工;横梁采用支架法施工,分2层浇注.主桥无索区钢梁采用膺架法架设,桥塔墩有索区钢梁采用架梁吊机对称伸臂架设;在3号墩设置桁内开启式提升站取梁;全桥设2个合龙口,先中跨、后边跨合龙.非通航孔桥64 m箱梁采用支架法现浇施工.水中墩平台、围堰及栈桥考虑不同设防水位.该桥已于2012年12月实现多点精确合龙.%Anqing Changjiang River Railway Bridge was arranged as a 4-track railway steel truss girder cable-stayed bridge with double pylons,triple cable planes and with 6 spans of 64-m cast-in-situ simply-supported box girders.The pylon piers No.3 and No.4 of the bridge in the deep water area were constructed by the scheme of double-wall steel cofferdams,in which the cofferdams were set up first and the working platforms were late.The pile foundation of the pier No.5 was constructed by the positioning pile platform and the pile cap of the pier was constructed by the double-wall steel cofferdam.The pile foundations of the piers No.6,No.7 and the piers W01 and W02 in the shallow water area were constructed by the twin trestle bridges and positioning pile platforms and the pile caps thereof were constructed by the steel sheet pile cofferdams.The starting segments of a pylon were constructed by the scaffolding method while the rest of the segments were constructed by the large segment hydraulic climbing formwork.The cross beam of the pylon was cast in two layers by the scaffolding method

  16. 液体黏滞阻尼器在乌锡线黄河特大桥中的应用研究%Application and Research of Fluid Viscous Damper to Yellow River Extra-long Bridge on Wu-Xi Railway

    Institute of Scientific and Technical Information of China (English)

    刘红绪

    2016-01-01

    The type of bridge structure for the main bridge of Yellow River extra-long bridge on Wu-Xi railway is a large cross-span continuous beam bridge with huge mass superstructure. The seismic fortification is the key technology of this project. In this paper, a spatial finite element model is built with Midas/civil and three seismic waves suitable for site grade and seismic characteristics of bridge site are selected. The anti-seismic effect of the fluid viscous damper device installed between the non-fixed pier and the main beam is calculated with nonlinear time history analysis method. By setting up fluid viscous damper between the non-fixed pier and the main girder, the non-fixed pier is effectively coordinated under the dynamic action, and the seismic force of the fixed pier is reduced. The seismic fortification standard of the main bridge is effectively improved.%乌锡铁路黄河特大桥主桥的桥式方案为长联大跨混凝土连续箱梁结构,梁部质量巨大,主桥的地震设防为本项目技术关键。利用Midas/civil建立空间有限元模型,选用适合桥址处场地等级及地震特性的3条地震波,采用非线性时程分析方法检算在活动墩与主梁之间设置液体黏滞阻尼器装置的抗震效果。结论为:在活动墩与主梁之间设置液体黏滞阻尼器装置,有效协调各活动墩在动力作用下的参与工作,降低固定主墩地震力,有效提高主桥的地震设防标准。

  17. 高墩大跨连续刚构桥的Pushover分析%Pushover analysis of high pier and long span continuous steel bridge

    Institute of Scientific and Technical Information of China (English)

    李青宁; 高依强; 朱坤

    2013-01-01

    Pushover法作为一种非线性静立分析方法,在基于结构位移/性能的抗震思想下有更为广泛的应用前景.结合工程实例,对高墩大跨连续刚构桥进行Pushover分析,其结果与非线性时程分析法比较,结果表明该方法对桥梁结构有较好的适用性和发展潜力.

  18. APPLICATION OF STEEL PIPE PILE LOADING TESTS TO DESIGN VERIFICATION OF FOUNDATION OF THE TOKYO GATE BRIDGE

    Science.gov (United States)

    Saitou, Yutaka; Kikuchi, Yoshiaki; Kusakabe, Osamu; Kiyomiya, Osamu; Yoneyama, Haruo; Kawakami, Taiji

    Steel sheet pipe pile foundations with large diameter steel pipe sheet pile were used for the foundation of the main pier of the Tokyo Gateway bridge. However, as for the large diameter steel pipe pile, the bearing mechanism including a pile tip plugging effect is still unclear due to lack of the practical examinations even though loading tests are performed on Trans-Tokyo Bay Highway. In the light of the foregoing problems, static pile loading tests both vertical and horizontal directions, a dynamic loading test, and cone penetration tests we re conducted for determining proper design parameters of the ground for the foundations. Design parameters were determined rationally based on the tests results. Rational design verification was obtained from this research.

  19. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2005-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  20. Fatigue tests on aluminium bridges

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.; Straalen, IJ.J. van

    2004-01-01

    Traffic bridges are subjected to variable loads and should therefore be checked on fatigue. Especially low weight materials, like aluminium, are sensitive to fatigue, because the variable load is a substantial part of the total load. This paper shows the structural design of an aluminium bridge load

  1. Numerical Modeling of the Lake Mary Road Bridge for Foundation Reuse Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Sitek, M. A. [Argonne National Lab. (ANL), Argonne, IL (United States); Bojanowski, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Lottes, S. A. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-04-01

    This project uses numerical techniques to assess the structural integrity and capacity of the bridge foundations and, as a result, reduces the risk associated with reusing the same foundation for a new superstructure. Nondestructive test methods of different types were used in combination with the numerical modeling and analysis. The onsite tests included visual inspection, tomography, ground penetrating radar, drilling boreholes and coreholes, and the laboratory tests on recovered samples. The results were utilized to identify the current geometry of the structure with foundation, including the hidden geometry of the abutments and piers, and soil and foundation material properties. This data was used to build the numerical models and run computational analyses on a high performance computer cluster to assess the structural integrity of the bridge and foundations including the suitability of the foundation for reuse with a new superstructure and traffic that will increase the load on the foundations. Computational analysis is more cost-effective and gives an advantage of getting more detailed knowledge about the structural response. It also enables to go beyond non-destructive testing and find the failure conditions without destroying the structure under consideration.

  2. Development of cooperative system bridges

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhe; WAN Qi-bai; SHI Lei

    2008-01-01

    Cooperative system bridges comprise several basic structures that act jointly to improve structural characteristics. We delved into the historical development of cooperative system bridges. Cooperative systems are classified as different-load cooperative systems and same-load cooperative systems by distinguishing the modes of load distribution. For different-load cooperation, individual basic structures are at different positions in the direction along bridge axis and carry the loads separately. While for same-load cooperation, all basic structures overlap in geometrical locations and support the entire loads conjointly. The choosing of span ratios between basic structures, the design of connections of different-load cooperative systems were discussed as well as optimizations of relative rigidity for same-load cooperative systems which greatly influence structural characteristics. The general situation and several structural measurements of several cooperative bridges were demonstrated. This information can assist engineers in developing their concepts in cooperative systems and can lead to more efficient and economical cooperative bridges.

  3. Cascaded resonant bridge converters

    Science.gov (United States)

    Stuart, Thomas A. (Inventor)

    1989-01-01

    A converter for converting a low voltage direct current power source to a higher voltage, high frequency alternating current output for use in an electrical system where it is desired to use low weight cables and other circuit elements. The converter has a first stage series resonant (Schwarz) converter which converts the direct current power source to an alternating current by means of switching elements that are operated by a variable frequency voltage regulator, a transformer to step up the voltage of the alternating current, and a rectifier bridge to convert the alternating current to a direct current first stage output. The converter further has a second stage series resonant (Schwarz) converter which is connected in series to the first stage converter to receive its direct current output and convert it to a second stage high frequency alternating current output by means of switching elements that are operated by a fixed frequency oscillator. The voltage of the second stage output is controlled at a relatively constant value by controlling the first stage output voltage, which is accomplished by controlling the frequency of the first stage variable frequency voltage controller in response to second stage voltage. Fault tolerance in the event of a load short circuit is provided by making the operation of the first stage variable frequency voltage controller responsive to first and second stage current limiting devices. The second stage output is connected to a rectifier bridge whose output is connected to the input of the second stage to provide good regulation of output voltage wave form at low system loads.

  4. Engineering Geological Investigation and Monitor of Jinglan Bridge Reconstruction in LiuZhou%柳州市静兰大桥改建工程地质勘察及监测

    Institute of Scientific and Technical Information of China (English)

    关键超; 韦少典

    2012-01-01

    柳州市静兰大桥改建工程是将一座1992年8月建成通车、总长550m、主桥为5孔90rn跨的钢筋混凝土箱肋拱桥拆除原地重建,使桥面宽度由原来的16.5m扩至31m,桥面标高由原来的97m升高至98.6m。原桥位于河水中的四个桥墩乃利用石灰岩作浅基础形式,潜水录像显示墩基结构基本完好,但原灌浆固结处理溶蚀沟槽里的砾卵石层已不同程度地被淘蚀。通过勘察工作分析,认为经过基底补强处理后,利用旧桥墩建新桥的方案是可行的。%LiuZhou Jinglan Bridge is a Reinforced concrete box arch bridge, the overall length 550m, The main bridge for 5 holes 90m cross and built in August 1992. The project of the bridge reconstruction is to dismantle and rebuild it in the same place and to broaden the width of the bridge from 16.5 to 31 m, heighten the demarcate height from 97m to 98.6m. The shallow basement modalities of the former four piers lying in the river is limestone, as the diving video shows, the framework of the pier foundation is in good condition. But the former gravel pebble stratum in the corrode groove which treated by grouting concretion has been scouring; Through reconnaissance and job analysis, I think it's feasible that build the new bridge which base on the former piers after reinforcing the fundus.

  5. 城市快速通道跨越铁路大型编组站桥梁方案比选研究%Comparison and Research of Urban Expressway Bridge Crossing Over Large Railway Marshalling Yard

    Institute of Scientific and Technical Information of China (English)

    周继; 张晓江; 田芳

    2016-01-01

    Nongye road expressway project crosses over the north marshalling yard of more than 30 tracks and Beijing-Guangzhou railway in Zhengzhou, and the existing road under the bridge passes through under the Zhengzhou north marshalling yard. There are many frame bridges and road bridges at the work site and the number of feasible pier location for the bridge is very few, which challenges the construction of the bridge. Thus, it is absolutely necessary to study and choose a reasonable bridge type for the project. The researches on some feasible pier locations and the selection of feasible construction program and span arrangement result in the determination of 4 bridge types, and one reasonable bridge type is recommended after analysis and comparison in terms of railway safety, technology, schedule and economy. The results show that the ( 126+200+126 ) m twin tower cable-stayed bridge is the recommended bridge type. The research process and method employed may provide references for the design of similar projects.%郑州市农业路快速通道工程上跨郑州北铁路编组站30余股道线及京广铁路,同时桥下既有道路下穿郑州北编组站。桥址处密布框架桥、公路桥,桥梁建设的可行性墩位少,施工方案影响桥梁方案。研究并选择合理的桥梁方案对本工程十分必要。通过对桥址处多个可行性墩位的研究,选择合理的施工方案和孔跨布置方案,进而确定4个桥梁方案,再从铁路安全、技术、工期、经济等方面对桥梁方案进行详细的分析比较,推荐合理的桥梁方案。比选结果表明:(126+200+126) m双塔斜拉桥为推荐桥梁方案,该桥梁方案的研究过程及方法可为同类型涉铁工程设计提供参考和借鉴。

  6. 汶川地震桥梁震害经验及抗震研究若干新进展%Lessons Learned from Wenchuan Seismic Damages and Recent Research on Seismic Design of Highway Bridges

    Institute of Scientific and Technical Information of China (English)

    王东升; 孙治国; 郭迅; 李晓莉; 霍燚

    2011-01-01

    The great Wenchuan earthquake, which measured as 8. 0 Ms and occurred on May 12, 2008 in Sichuan province of China, has caused severe damage to many highway bridges and also left us with valuable information that can be analyzed to reduce potential losses associated with future earthquakes. The Lessons learned from Wenchuan seismic damages of highway bridges were summarized. It is believed that special attention should be paid to (1) bridge seismic response and unseating damages subjected to near-fault ground motions; ( 2 ) preventive design of collapse damage of curved girder bridges with small radius; ( 3 ) ductility and seismic design, detailed reinforcement of bridges and seismic damage control of high-rise piers under deep water. The recent research progress of our research team on seismic performance of highway bridges was summarized. It includes design idea and method of unseating protection of highway bridges, deformation capacity and shear strength of PC bridge piers, numerical simulation of seismic damage mechanism of curved girder bridges, and countermeasures to prevent collapse of curved girder bridges with small radius.%2008年5月12日我国四川省汶川县发生8.0级大地震,造成大量公路桥梁破坏,并为桥梁抗震研究留下了众多资料.总结了汶川地震桥梁震害经验,认为宜重视桥梁近断层地震动响应及防落梁措施、小半径曲线梁桥地震防倒塌设计、桥梁延性抗震设计及细部配筋和深水高桥墩地震损伤及控制等抗震问题.综述了课题组近些年对桥梁抗震研究的若干新进展,包括梁式桥防落梁抗震设计理念及方法、钢筋混凝土桥墩地震抗剪强度及变形能力研究、曲线梁桥地震破坏机理数值分析与小半径曲线梁桥地震防倒塌设计对策等.

  7. 工具式围堰在桥梁墩柱维修中的应用%Operation Method of the Tool-typed Recycling Double Wall Steel Cofferdam in Wate-pier Reinforcement Engineering in the Spring Tide of Poor Water

    Institute of Scientific and Technical Information of China (English)

    刘昂; 吴中鑫; 朱慈祥

    2015-01-01

    In this paper,in the engineering background of detection and reinforcement project of the No.14~18 Pier of a bridge,the construction method of the Tool-Typed Double Wall Steel Cofferdam in the bridge of low clearance flyovers which is removable and recyclable in the spring tide of poor wa-ter is introduced.In the method,the factors,the spring tide of poor water,low clearance flyovers, and details of design and fabrication of the steel cofferdams are considered.An application example shows that the method can reduce construction time,cost,energy conservation and environmental protection..%以某桥梁15~18号桥墩检测加固项目为工程背景,介绍了某桥梁高潮差低净空下的工具式可拆卸循环利用双壁钢围堰使用方法,该工具式可拆卸循环利用双壁钢围堰的施工考虑了涨落潮变化、桥下净空较小等环境因素,以及围堰及辅助措施的设计、制作安装。应用证明,该方法具有减少施工工期、降低成本、节能环保等特点。

  8. Analysis of seismic response of continuous rigid-frame bridge by considering the effect of the traveling wave%考虑行波效应的连续刚构桥地震响应分析

    Institute of Scientific and Technical Information of China (English)

    徐国英; 李明; 苗玉

    2015-01-01

    以某连续刚构桥为工程背景,运用有限元计算软件ANSYS对其进行数值模拟分析,求出了结构的自振频率、振型等动力参数。选择EL—Centro波作为激励,运用大质量法,采用时程分析法分析行波效应对结构动力响应的影响。分析结果表明:行波效应增大了桥墩的轴力,对桥墩的位移、横桥向弯矩和剪力影响不大,桥墩顺桥向的弯矩和剪力有不同程度的削弱。%Taking a continuous rigid frame bridge as an example,this paper obtained the structure's natural frequencies and virbration modes by using the finite element software ANSYS.Choosing EL-Centro wave as exciation,by way of great mass method and using time-history analysis method ananlysis the effect of traveling wave to structure dynamic response.The analysis results show that the traveling wave effect increases the axial force of the bridge piers and having little effect to the displacement,shear and moment in cross-bridge direction.The moment and shear of the main bridge piers are decresed at various degrees due to the traveling wave effect along the bridge direction.

  9. Liquid-Bridge Breaking Limits

    Science.gov (United States)

    Macner, Ashley; Steen, Paul

    2011-11-01

    Wet adhesion by liquid bridges in large arrays shows promise for use in lightweight, controllable on-demand devices. Applications include grab/release of wafer substrates, transport of micron-sized tiles for use in 3D printing and micro-dosing of personalized pharmaceutical drugs. By wetting and spreading, a drop can form a bridge and thereby ``grab'' a nearby solid substrate. By volume decrease or extension, the bridge can break. The breaking limit corresponds to bridge instability which can be predicted, knowing the static mechanical response of the bridge. Mechanical behaviors include force-volume (FV), pressure-volume (pV) and force-length (FL) responses. Instability crucially depends on the mode of failure - failure under constant-force or constant length are typical cases. We study single bridge equilibria for their breaking limits. FV diagrams for the pin-pin equal and pin-pin unequal radii boundary conditions for different bridge heights are measured in the laboratory. The FL response in the case of pin-pin equal radii is also measured. Results are compared to predictions of static theory. Static results are then used to compare to dynamical sequences where volume is driven quasistatically by syringe or an electro-osmotic pump. As the breaking limit is approached, the shape deformation accelerates leading to non-equilibrium shapes not captured by the static analysis.

  10. 桥墩覆膜补水养护新方法%Water Conservation of Piers by Using Film

    Institute of Scientific and Technical Information of China (English)

    周渊韬

    2013-01-01

      本文在深入了解混凝土养护重要性的基础上,针对桥梁墩台养护作业面临的困境及存在的问题,推荐了覆膜+补水养护的新方法,详细介绍了加压上水装置的组成和使用方法,谨供工程技术领域同行参考。%The paper analyzes the importance of concrete conservation. Aiming at the difficulties in pier conservation, the paper puts forward a new method of film and water conservation, and presents the component of pressurized water equipment and use, for serving as reference for the peer.

  11. Application of Microtremor Measurement Techniques to Detection of Structural Damage of an Ancient Arch Bridge%微动测试技术在古建筑拱桥结构检测中的应用①微动测试技术在古建筑拱桥结构检测中的应用

    Institute of Scientific and Technical Information of China (English)

    范岩旻; 车爱兰; 陈峰; 曹永康

    2015-01-01

    the observation of mutation of the vibration mode,quantitative evaluation of the structural damage is performed by comparing the deformation features of the structure after locating where the structural damage has occurred.Based on the experimental analysis of this study and consider-ing the structural characteristics and the present situation of the damage,the observation point is set.The location and form of the damage is qualitatively delimited and the three modal distribu-tions of the Yingxiang Bridge are obtained using microtremors.Comparing the three natural fre-quencies of the numerical results with the microtremor measurements,the significant weaknesses in the whole structure are determined.There is some damage to the Yingxiang Bridge.According to the measurement results,the bridge pier D is damaged most seriously.This indicates that the concrete curing of the middle bridge pier caused the imbalance of stiffness.The Yingxiang Bridge needs reinforcement by concrete,with large amounts in the middle pier of the bridge,to ensure sufficient stiffness to load bearing.In conclusion,microtremor measurements are useful in the detection of damage to ancient arch-bridges.

  12. Bridge Creek IMW database - Bridge Creek Restoration and Monitoring Project

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The incised and degraded habitat of Bridge Creek is thought to be limiting a population of ESA-listed steelhead (Oncorhynchus mykiss). A logical restoration...

  13. National Bridge Inventory - National Geospatial Data Asset (NGDA) Bridges

    Data.gov (United States)

    Department of Transportation — The NBI (NTAD 2015) is a collection of information (database) describing the more than 610,000 of the Nation's bridges located on public roads, including Interstate...

  14. Complex Testing of the Bridges

    Directory of Open Access Journals (Sweden)

    Savić Adrijana

    2016-01-01

    Full Text Available This article describes the process of examining bridges. AB road bridge, founded on the columns by the Karpoš system and damaged due to erosive action of the river, is given as an example. The first tests of the bridge are conducted on the impact load of V 300, because of the appearance of longitudinal cracks. The results of the columns testing are presented in this paper, as well as the rehabilitation measures thus increasing the load capacity of the column.

  15. Thermal bridges of modern windows

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan de Place; Møller, Eva B.; Nielsen, Anker;

    2013-01-01

    With its focus on reduced energy consumption, contemporary housing construction requires a highly insulated and airtight building envelope with as few thermal bridges as possible.Windows must be carefully designed, as thermal bridges can lead to surface condensation or mold growth, even...... if the window has an U-factor of 1 W/(m2·K) or lower. This paper describes the development of modern, energy efficient Danish windows with reduced thermal bridges. It focuses on materials, geometry, and sealing of window panes based on a literature review. Examples of modern windows are presented. Experience...

  16. Reliability Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Middleton, C. R.

    This paper is partly based on research performed for the Highways Agency, London, UK under the project DPU/9/44 "Revision of Bridge Assessment Rules Based on Whole Life Performance: concrete bridges". It contains the details of a methodology which can be used to generate Whole Life (WL) reliability...... profiles. These WL reliability profiles may be used to establish revised rules for concrete bridges. This paper is to some extend based on Thoft-Christensen et. al. [1996], Thoft-Christensen [1996] et. al. and Thoft-Christensen [1996]....

  17. Overall Design and Study of South and North Bridges of Xiazhang Sea-Crossing Bridge%厦漳跨海大桥南、北汊桥总体设计与研究

    Institute of Scientific and Technical Information of China (English)

    王福敏; 罗强; 李军

    2013-01-01

    厦漳跨海大桥主要由北汊桥、海门岛立交及收费服务区、南汊桥、海平立交四大部分组成,全长9.333 km.为适应复杂的自然与建设条件,对该桥桥位方案进行比选,并对项目中关键控制性工程(北汊主桥、南汊主桥)的桥型方案进行研究.经研究,最终确定北汊主桥采用主跨780m的五跨连续钢箱梁斜拉桥方案,南汊主桥采用主跨300 m的结合梁斜拉桥方案.针对项目中复杂的地质条件、高地震烈度和恶劣的风环境,分别采取设置适应性强的桩基础,对较差的桩基地质注浆;按抗震要求进行构造设计,在主桥塔梁处设置纵向阻尼器,引桥设置减隔震支座;北汊主桥采用一种翼型扶手栏杆、南汊主桥采用分流板抗风等措施进行处理.%The Xiazhang Sea-Crossing Bridge,totally 9.333 km long,is composed of four major parts of the north bridge,Haimen Island interchange and toll service area,south bridge and Haiping interchange.To accommodate the complicated natural and construction conditions of the bridge,the bridge site schemes were compared and the bridge type schemes for the critical control projects (the north and south main bridges) were studied.According to the study,it was finally determined that the 5-span continuous steel box girder cable-stayed bridge with a main span 780 m would be adopted for the north main bridge and the composite girder cable-stayed bridge with a main span 300 m would be adopted for the south main bridge.In consideration of the complicated geologic conditions,high intensity earthquake and harsh wind environment,the well adaptive pile foundations were respectively utilized.For the pile foundations at the locations with poor geology,the foundations would be grouted.The structures of the bridge were designed in compliance with the seismic resistance requirements.At the connections between the pylons and girders of the main bridges,the longitudinal dampers were arranged and on the piers

  18. 荆岳铁路洞庭湖大桥主桥抗风分析%Wind Resistant Analysis of Jing Yue Railway Dongting Lake Bridge

    Institute of Scientific and Technical Information of China (English)

    谭冠生

    2014-01-01

    \\The space finite element model analysis of Jing Yue Railway Bridge in Dongting Lake is performed to study the dynamic characteristics of bridge operation state and the whole process of con-struction and evaluate the wind resistance safety performance.Analysis result shows that the long ca-ble outside the middle tower has a certain role of constraining the longitudinal displacement of the bridge tower.The restriction role of transition pier and auxiliary pier to the horizontal and vertical vi-bration is more obvious.The main girder is made up of steel truss beam and has high torsion rigidity. The critical wind velocity of coupled bending torsion flutter and separated-flow torsion flutter of each working state exceed their flutter test speed.The wind resistance safety requirements are satisfied.%采用空间有限元模型分析荆岳铁路洞庭湖大桥主桥在成桥运营状态和施工全过程中的动力特性,评估主桥抗风安全性能。分析表明,中塔外边的长索对约束中塔纵桥向位移有一定的作用,过渡墩、辅助墩对主梁的横向和竖向振动的制约作用比较明显。主梁为钢桁梁,扭转刚度大,各工况的主梁弯扭耦合颤振和分离流扭转颤振的临界风速均超过了各自的主梁颤振检验风速,满足抗风安全性要求。

  19. 粉房湾长江大桥主桥钢桁梁架设施工技术%Construction Techniques for Erection of Steel Truss Girder of Main Bridge of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    王存贵; 王殿永; 高杰; 靳春尚

    2012-01-01

    The main bridge of Fenfangwan Changjiang River Bridge in Chongqing City is a semi-floating system steel truss girder cable-stayed bridge with double pylons, double cable planes and with span arrangement (216. 5 + 464 + 216. 5) m. The main girder of the bridge is designed as the steel truss girder structure erected by the piece-by-piece assembling. In the light of the topographic conditions of the south and north banks, the asymmetric way of erection was chosen for the girder. The steel truss girder on the south bank side was erected from the side span towards the central span. The girder of the side span was assembled on the scaffolding, the girder in the middle was erected first and then the components like the edge stringers and edge deck plates were erected, using the deck truck cranes. The girder for the main span was erected by the cantilever assembling method. The girder of the north bank was erected by the balanced two-cantilever assembling method and the 5 blocks of the girder atop and on both sides of a main pier were assembled on the pier-side brackets.%重庆粉房湾长江大桥主桥为跨度(216.5+464+216.5)m的双塔双索面半飘浮体系钢桁梁斜拉桥,主梁采用钢桁梁结构.钢桁梁采取散拼架设,南、北岸钢桁梁根据地形情况选取了不对称的方式施工.南岸钢桁梁由边跨向中跨架设,边跨钢桁梁采用支架拼装,先架设中间桁架,再利用桥面汽车吊架设边纵梁、边桥面板等构件;主跨钢桁梁采用悬臂拼装.北岸钢桁梁采用双悬臂对称架设,主墩墩顶及两侧共5个节段钢桁梁采用墩旁托架拼装.

  20. The Higgs Bridge

    CERN Document Server

    Allen, Roland E

    2013-01-01

    The particle recently discovered at the Large Hadron Collider near Geneva is almost certainly a Higgs boson, the long-sought completion of the Standard Model of particle physics. But this discovery, an achievement by more than six thousand scientists (including students), is actually much more than a mere capstone of the Standard Model. It instead represents a bridge from the Standard Model to exciting discoveries of the future, at higher energies or in other experiments, and to the properties of matter at very low temperatures. The mere existence of a particle with zero spin implies a need for new physics, with the most likely candidate being supersymmetry, which requires that every known particle has a superpartner yet to be discovered. And phenomena similar to the Higgs are seen in superconducting metals and superfluid gases at low temperatures, which extend down to a millionth or even a billionth of a degree Kelvin. So the discovery of a Higgs boson has a central place in our attempts both to achieve a tr...

  1. Scheme of Pressure Boost and Floating Aid for Steel Open Caisson of Main Ship Channel Bridge of Hutong Changjiang River Bridge%沪通长江大桥主航道桥钢沉井增压助浮方案

    Institute of Scientific and Technical Information of China (English)

    余允锋; 邱琼海; 王立忠

    2015-01-01

    The main ship channel bridge of the Hutong Changjiang River Bridge is a double-py-lon continuous steel truss girder cable-stayed bridge with span arrangement (140+462+1 092+462+140) m .T he foundations for the main piers of the bridge are all the open caissons ,of w hich the plan dimensions of the caisson top of the main pier No .29 are 86 .9 m × 58 .7 m and in the plan of the caisson ,24 well holes are arranged .The total height of the caisson of the pier is 115 m and the lower part of the caisson is the steel caisson that is 56 m in height .In the state of free floating , the draught of the steel caisson is 12 .5 m ,the caisson can not be floated out of the shipyard be-cause of the deep draught and has the risk of grounding in the floating .To reduce the draught of the caisson and to keep the pressure in the air cabins of the caisson stable ,the scheme of pressure boost and floating aid for the caisson was proposed ,that was ,12 well holes in the caisson were symmetrically closed to make the well holes the sealed cabins .Meanwhile ,the active pressure boost system was arranged and the air was injected into the cabins from the tops of the closing cov-er plates of the well holes .The pressure boost system was composed of the air compressor ,main air pipes ,branch air pipes ,extension air pipes ,air pressure meters ,check valves ,stop valves and liquid level sensors .By the measures of injecting the air for pressure boost and releasing the air for pressure reduction ,the air pressure in each cabin was controlled .With the scheme of the pressure boost and floating aid ,the steel open caisson of the pier was finally floated out from the shipyard to the pier site only in 3 h and the effect of the scheme implementation was sound .%沪通长江大桥主航道桥为(140+462+1 092+462+140 ) m双塔连续钢桁梁斜拉桥 ,该桥主墩均采用沉井基础 ,其中 ,29号主墩沉井顶平面尺寸为86 .9 m × 58 .7 m ,平面布置24个井孔 ,高115m,下部钢沉井高56

  2. Mineral bridges in nacre revisited

    CERN Document Server

    Checa, Antonio G; Willinger, Marc-Georg

    2012-01-01

    We confirm with high-resolution techniques the existence of mineral bridges between superposed nacre tablets. In the towered nacre of both gastropods and the cephalopod Nautilus there are large bridges aligned along the tower axes, corresponding to gaps (150-200 nm) in the interlamellar membranes. Gaps are produced by the interaction of the nascent tablets with a surface membrane that covers the nacre compartment. In the terraced nacre of bivalves bridges associated with elongated gaps in the interlamellar membrane (> 100 nm) have mainly been found at or close to the edges of superposed parental tablets. To explain this placement, we hypothesize that the interlamellar membrane breaks due to differences in osmotic pressure across it when the interlamellar space below becomes reduced at an advanced stage of calcification. In no cases are the minor connections between superimposed tablets (< 60 nm), earlier reported to be mineral bridges, found to be such.

  3. Simulation of multivariate diffusion bridges

    DEFF Research Database (Denmark)

    Bladt, Mogens; Finch, Samuel; Sørensen, Michael

    We propose simple methods for multivariate diffusion bridge simulation, which plays a fundamental role in simulation-based likelihood and Bayesian inference for stochastic differential equations. By a novel application of classical coupling methods, the new approach generalizes a previously...

  4. Applications of overburden conveyor bridges

    Energy Technology Data Exchange (ETDEWEB)

    Schachtschneider, H.

    1987-06-01

    In large scale surface mines of the capacities required today, a cross-pit operation with overburden conveyor bridges is the most economical method of overburden removal and disposal. In order to provide the production capacity required in surface mining equipment by the GDR brown coal industry, VEB Schwermaschinenbau Lauchhammerwerk undertook the design and manufacture of standard overburden conveyor bridges for cut heights of 34 m, 45 m and 60 m. All three base types may be equipped to match the site specific geological and geotechnical conditions, and to meet customer's demands. Specifications of the bridges are given as well as details of conveyor belt speeds, modifications to the standards, and number manufactured. Design problems faced with the 60 m bridge are discussed, together with details of the superstructure, method of operation, transportation rates, structural steel used, assembly and power supply. 5 refs.

  5. Bridge Culture of Langde Village

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Langde, a village in Leishan County ofsouthwestern Guizhou province, is known for itslarge number of unique bridges bearing the distinctdesign style of the Miao ethnic group. Animpressive variety of well-preserved ancient

  6. ANGIOGRAPHIC ASPECTS OF MYOCARDIAL BRIDGES

    Directory of Open Access Journals (Sweden)

    Sujatha. M

    2015-12-01

    Full Text Available Introduction: The segment of epicardial coronary artery that traverses intramurally through the myocardium and bridged by a bunch of cardiac muscle fibers is called tunneled artery or intramural artery. The band of cardiac muscle fibers passing over the tunneled artery segment is named as myocardial bridge. During angiography milking effect is observed during systole due to the external pressure of muscle fibers on the tunneled artery that leads to narrowing of vessel lumen and further ischemia. Materials & Methods: It is a prospective study performed from 2012- 2015 in cardiac centers available around Tirupati, Andhra Pradesh, South India. A total number of 2015 adult patients who underwent diagnostic coronary angiography were evaluated to detect myocardial bridges. With the informed consent the relevant data was collected from the patients and analyzed. Results: The prevalence of myocardial bridges was 3.17%. Among the 2015 patients 70.7% are males and 29.2% are females. Among 64 myocardial bridge positive cases 62.5% were male and 37.5% were female patients. Regarding coronary dominance 84% were right dominant and 14.4% were left dominant and 1.6% are balanced. The percentage incidence of myocardial bridging according to dominance was 3.01% for right dominant patients, 4.12% for left dominant patients and 3.1% for balanced dominant patients. In all the myocardial bridge positive cases they were located on the left anterior descending artery (LAD. According to diagnosis the patients with normal coronaries were 22.6%, patients with MILD CAD were 17.9%, patients with single vessel disease were 23.4%, patients with two vessel disease were 14.7% and the patients with triple vessel disease were 21.3%. The 64 myocardial bridging cases were grouped in to three groups according to their age. Incidence of double bridges was observed in 3 cases of which 66.7% males & 33.3% in females. Conclusion: These results show that Andhra Pradesh population are

  7. The stories of two bridges in Ghana

    DEFF Research Database (Denmark)

    Andreasen, Jørgen

    2004-01-01

    Public participation in bridge building was promoted by un habitat in the village of Mankrong. The neighbouring village did not participate in the construction of their bridge. The first flooding washed the second bridge down while the "participative bridge" stood up....

  8. An Expert System for Concrete Bridge Management

    DEFF Research Database (Denmark)

    Brito, J. de; Branco, F. A.; Thoft-Christensen, Palle;

    1997-01-01

    The importance of bridge repair versus new bridge construction has risen in recent decades due to high deterioration rates that have been observed in these structures. Budgets both for building new bridges and keeping the existing ones are always limited. To help rational decision-making, bridge...

  9. Unseating Damage to Simply Supported Bridges during Wenchuan Earthquake and Design Countermeasures%汶川大地震简支梁桥落梁震害与设计对策

    Institute of Scientific and Technical Information of China (English)

    王东升; 王吉英; 孙治国; 李晓莉

    2011-01-01

    The unseating damage to simply supported bridges and their main influencing factors during the Wenchuan earthquake are summarized. It is found that excepting the earthquake-induced landslide hazard, the earthquake surface rupture, near fault ground motion, punching shear failure of the abutment breast wall, the invalidity of the devices for preventing unseating damage to the bridges and the complex bridge types are main influencing factors leading to the unseating damage to the simply supported bridges. Basic seismic design idea and method to prevent unseating damage to simply supported bridges are presented in this paper, which include: (1) sliding between bridge girders and cap beams is allowed to reduce the seismic actions concentrated on the bridge piers; (2) cap beams with enough seating length are recommended for sliding between girder and pier to avoid unseating damage; (3) shear keys or cable restrainers should be used as added measures to prevent unseating damage. The design method for simply supported bridges with cable restrainers is illustrated in detail by using current seismic design code for bridges.%总结了5· 12汶川大地震中简支梁桥落梁震害及主要影响因素,发现除地震山体滑坡等地质灾害外,断层地表破裂、近断层地震动效应、桥台胸墙冲切破坏、防落梁构造措施单一及桥梁体型复杂等因素都是引起简支梁桥落粱震害的重要原因.提出了简支梁桥防落梁设计的基本理念及相关技术方案要点为允许墩梁间发生滑移,以降低桥墩承受的地震惯性力,以及盖梁提供允许的最大滑移长度及支座支承宽度,再辅助挡块或拉索限位器等共同防止落粱发生.最后结合现行规范,以拉索限位器为例给出了简支梁桥防落梁设计方法.

  10. Stability of liquid crystalline bridges

    Science.gov (United States)

    Mahajan, Milind P.; Tsige, Mesfin; Taylor, P. L.; Rosenblatt, Charles

    1999-02-01

    The stability of cylindrical bridges of the liquid crystal octylcyanobiphenyl in an immiscible liquid bath was investigated in the nematic and smectic A phases. In the nematic phase the bridge was found to destabilize at a length-to-diameter (slenderness) ratio R similar to that of ordinary Newtonian fluids. On the other hand, the Bingham behavior of the smectic A phase, i.e., an apparent yield stress, enabled the formation of stable columns with R well in excess of π.

  11. 矮塔斜拉桥结构力学行为研究与设计实践%Cable Force Optimization and Design Practice of Low Tower Cable-stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    沐云秋

    2016-01-01

    With the development of bridges technology, as a combination bridge between the cable-stayed bridge and continuous girder that cable-stayed bridge with Low Towers is more and more applied, in recent ten years. This bridge belongs to the low tower cable-stayed bridge of pylon girder pier of Twin Towers and double cable plane. Extradited cable-stayed bridge has many mechanical properties are intermediate between the continuous rigid frame bridge and cable-stayed bridge, is by the beam bending, compression and cable tension to bear vertical loads. This design uses the MIDAS/Civil analysis program, provides analysis of data for each part of the design timely, and optimizes the cable which have a surplus volume of safety factor. The girder stress condition is further improved by appropriately adjusting the cable force.%随着桥梁技术的发展,矮塔斜拉桥作为介于斜拉桥和连续梁(刚构)之间的一种组合体系桥型,近十年来应用较多.本桥就属于塔梁墩固结的双塔双索面矮塔斜拉桥.矮塔斜拉桥有许多力学特性都介于连续刚构和斜拉桥之间,是以梁的受弯、受压和索的受拉来承受竖向荷载.本次设计采用MIDAS/Civil分析程,及时为各个设计环节提供分析数据并对安全系数有富余量的拉索进行优化,通过适当调整索力进一步改善主梁的受力状况.

  12. «O utinam anima mea esset in corpore tuo!». Pier Damiani, l’amicitia monastica e la riforma

    Directory of Open Access Journals (Sweden)

    Umberto Longo

    2010-06-01

    Full Text Available L'amicizia si esprimeva attraverso la densissima serie di relazioni di Pier Damiani con una folla di interlocutori, a cominciare dai membri della sua comunità per finire con i monaci di Cassino e Cluny. Una speciale sensibilità emotiva e la condivisione di peculiari comportamenti ascetici e penitenziali alimentavano la forza vincolante che orientava la ristretta cerchia degli asceti seguaci di Pier Damiani a sviluppare, attorno alla passione di Gesù, una teologia per cercare di vivere la propria carne. Per quanto riguarda gli anni '60 del secolo XI si cerca di estendere la proposta di perfezione ascetica di questa cerchia, in particolare verso il monachesimo di Cassino.

  13. 粘滞性阻尼器在高速铁路长联大跨连续梁中的应用%Application of viscous damper devices in the seismic design of long span and long unit continuous girder bridges on high speed railway

    Institute of Scientific and Technical Information of China (English)

    宋子威; 蔡小培

    2012-01-01

    以杭州钱江铁路新桥主桥(45+65+14×80+65+45)m预应力混凝土连续箱梁为工程背景,利用有限元软件Midas/civil建立有限元模型。采用非线性时程分析方法计算设置粘滞性阻尼器前后墩底反力和墩顶位移的变化,从而评价粘滞性阻尼器对提升桥梁抗震性能的作用。结果表明:粘滞性阻尼器的合理设置可以减小制动墩内力,提升高速铁路长联大跨连续梁的抗震性能。%A dynamic finite element model was built using the finite element software Midas/civil with the new Hangzbou Qianjiang Railway Bridge as the practical engineering example, which has a main bridge of (45 + 65 + 14 × 80+65 + 45) m prestressed concrete continuous girder. A non-linear dynamic time history analysis method was used to calculate and compare the internal forces of the pier bottom and the displacements of the pier top before and after the setup of viscous dampers with the viscous dampers' impact on the seismic performance then evaluated. The results show that the force of the fixed pier can be significantly reduced via reasonable setup of viscous dampers, which leads to improvement of seismic performance of a long-spanned and long-unit continuous girder bridge on high speed railway.

  14. 独塔斜拉桥非线性动力特性有限元分析%Finite Element Analysis of Nonlinear Dynamic Characteristics of Single Pylon Cable-Stayed Bridge

    Institute of Scientific and Technical Information of China (English)

    何军拥

    2012-01-01

      自振频率是评价桥梁动力性能的重要依据。结合某斜拉桥工程设计实例,考虑结构的非线性,采用大型有限元分析程序ANSYS建立三维有限元模型。以等效弹性模量法模拟拉索,利用主从约束模拟塔梁的连接及边墩、辅助墩与主梁的连接;主塔与主梁之间设纵向阻尼器,模拟纵向漂浮体系,对模型进行动力分析,其分析结果为桥梁维修和养护提供参考意见。%  Natural frequencies are critical bases to evaluate the dynamic performance of bridges. This paper takes a large cable-stayed bridge as an example and a finite element computing model is set up for this bridge based on software ANSYS, which is to carry out modal analysis and get relevant modal parameters. The equivalent elastic modulus method is applied to analog cable modulus. The master-slave constraint is used to analog tower and beam connections, the side piers, auxiliary pier and beam connection, and longitudinal damper located between the main beam and the main tower, to simulate vertical float system. The results may be used as reference in bridge inspection etc.

  15. Floating liquid bridge charge dynamics

    Science.gov (United States)

    Teschke, Omar; Soares, David Mendez; Gomes, Whyllerson Evaristo; Valente Filho, Juracyr Ferraz

    2016-01-01

    The interaction of liquid with electric fields is investigated in a configuration where up to 13 kV are applied between electrodes resulting in a 106 V/m electric field in the capillaries and where there is the formation of a free-standing fluid bridge in the interelectrode gap. The Mott-Gurney equation was fitted to the measured ionization current vs applied voltage curve which indicates that the ionization rate at the high-voltage anode electrode dimethylsulfoxide (DMSO) interface and space charging in the interelectrode gap determine the floating liquid bridge current for a given cathode-to-anode voltage. Space charge effects were measured in the cathode becker and also at the liquid bridge since the ionized charges at the anode migrate to the bridge outer surface and decrease the interfacial tension from 43 mJ/m2 to 29 mJ/m2. Two distinct structural regions then form the bridge, a charged plastic (bulk modulus ˜100 MPa) conducting outer layer with a surface conductivity of ˜10-9 Ω-1, which shapes and supports the floating fluid structure, and an inner liquid cylinder, where DMSO molecules flow.

  16. A strange bridge by Leonardo

    CERN Document Server

    Huylebrouck, Dirk

    2013-01-01

    On folio 855 recto of the Codex Atlanticus, Leonardo da Vinci drew three 'easily movable' bridges, but one of them is enigmatic: all 'replicas' in Leonardo museums and exhibitions come as a surprise, to say the least, to any engineer or architect whose attention is drawn to it. This is the case for models in Amboise (France), Chicago and Portland (USA), Florence (Italy) and for the one of the traveling exhibition by the Australian company 'Grande Exhibitions' that already visited 40 major cities in the world. All 'replicas' of the bridge model attributed to Leonardo have pillars standing on the deck of the bridge, while the deck is suspended by cables attached on these pillars. At first sight this problem does not catch the attention of the observer, as the bridge seems to be a mixed form of a beam and a suspension bridge, but it was not overlooked by my colleague architect-engineer Dr. Laurens Luyten (Gent, Belgium). Yet, after a TV-interview in Brussels so much pressure was exerted by some of the museum col...

  17. 流冰撞击力作用下列车-简支梁桥耦合振动分析%Coupled vibration analysis for train and simply-supported bridge system subjected to floating-ice collision

    Institute of Scientific and Technical Information of China (English)

    夏超逸; 雷俊卿; 张楠

    2012-01-01

    A coupled vibration analysis model was established for train-bridge system subjected to floating-ice collision load. The force originated from the floating-ice collision, whose time history was measured in site experiment was taken as the load applied on the bridge piers in transient style. The dynamic responses of railway bridges subjected to floating-ice collision and their influences on the running safety of high-speed trains were analyzed by numerical simulation. The time history of a train traveling on a seven梥pan simply-supported bridge with 24m box girders when the floating-ice strikes bridge piers was simulated and the dynamic responses of the bridge and train vehicles were investigated. The calculation results show that the lateral acceleration of the bridge and running safety indices such as the derailment factors and offload factors of train vehicles will exceed the corresponding allowances when the train speed is higher than 250 km/h, indicating that collision of floating-ice has obvious effect on coupled vibration responses of train-bridge system.%建立撞击荷载作用下列车-桥梁系统动力分析模型,将现场实测的流冰撞击力时程作为系统的撞击荷载.通过计算机仿真分析,对流冰撞击作用下高速铁路桥梁的动力响应及其对桥上列车运行安全的影响进行研究.采用自编程序模拟列车过桥的全过程,计算分析7m×24 m简支箱梁桥在流冰撞击力作用下动力响应及桥上高速列车的动力响应.计算结果表明,在实测流冰撞击力作用下,桥梁横向加速度以及车辆脱轨系数和轮重减载率等行车安全指标在列车速度250 km/h以上时超过容许值,说明流冰撞击作用对车桥系统耦合振动响应具有较大的影响.

  18. 乌苏大桥主桥上部结构设计与计算%Design and Calculation of Superstructure of Main Bridge of Wusu Bridge

    Institute of Scientific and Technical Information of China (English)

    康晋; 肖海珠; 徐伟

    2011-01-01

    The main bridge of the Wusu Bridge is a single pylon and single cable plane cablestayed bridge with span arrangement (140+140) m and with a structural system of rigid fixity of the pylon, pier and girder. A summarized account of the design and calculation of the superstructure of the bridge is presented herewith. The main girder of the bridge is a composite girder with long cantilevers, the central part of the girder is designed as a two-cell and single-box steel girder and the steel cantilever at each side of the girder is the variable depth I-beam and is provided wiht a trough stringer at the far side, which are all topped with 25 cm thick concrete deck slabs connected with the girder via shearing studs. The part of the main girder close to the pylon is designed as a prestressed concrete box girder to facilitate the fixity of the girder with the pylon. The pylon is the single column pylon, 117 m in height. The stay cables, made up of low relaxation galvanized high strength parallel steel wire strands, are of the harp pattern cable plane arranged in the central alignment of the bridge deck. The finite element software MIDAS Civil 2006 and the SCDS programme are employed to calculate and analyze structure of the bridge. The results of the calculation and analysis indicate that the static, stability and dynamic characteristics of the bridge can meet the requirements in the relevant codes.%乌苏大桥主桥为独塔单索面斜拉桥,跨径布置为(140+140) m,采用塔、墩、梁固结体系,综述该桥上部结构设计与计算.主梁为带大挑臂的钢箱结合梁,中间钢箱梁采用单箱双室截面,两侧钢挑臂为变高度工字形梁,挑臂端部设槽形小纵梁;混凝土桥面板厚25 cm,与钢梁通过剪力钉连接;塔根部主梁采用预应力混凝土箱梁,以方便与桥塔固结;桥塔采用独柱式塔,高117 m;斜拉索为竖琴形中央平行索面布置,采用低松弛镀锌高强度平行钢丝束.采用有限元软件MIDAS Civil

  19. Bridging history and social psychology

    DEFF Research Database (Denmark)

    Glaveanu, Vlad Petre; Yamamoto, Koji

    2012-01-01

    This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other’s work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social...... hand historians can enhance their analysis of historical sources by drawing upon the conceptual tools developed in social psychology. They can “test” these tools and contribute to their validation and enrichment from completely different perspectives. Most important, as contributions to this special......-traditionalized societies—a distinction that lies at the heart of many social psychology accounts of the world we live in. The present editorial will introduce and consider this act of bridging history and social psychology by focusing on three main questions: What is the bridge made of? How can the two disciplines...

  20. Excitation Methods for Bridge Structures

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Duffy, T.A.; Cornwell, P.J.; Doebling, S.W.

    1999-02-08

    This paper summarizes the various methods that have been used to excited bridge structures during dynamic testing. The excitation methods fall into the general categories of ambient excitation methods and measured-input excitation methods. During ambient excitation the input to the bridge is not directly measured. In contrast, as the category label implies, measured-input excitations are usually applied at a single location where the force input to the structure can be monitored. Issues associated with using these various types of measurements are discussed along with a general description of the various excitation methods.

  1. Bridge Number and Conway Products

    OpenAIRE

    Blair, Ryan C.

    2007-01-01

    Schubert proved that, given a composite link $K$ with summands $K_{1}$ and $K_{2}$, the bridge number of $K$ satisfies the following equation: $$\\beta(K)=\\beta(K_{1})+\\beta(K_{2})-1.$$ In ``Conway Produts and Links with Multiple Bridge Surfaces", Scharlemann and Tomova proved that, given links $K_{1}$ and $K_{2}$, there is a Conway product $K_{1}\\times_{c}K_{2}$ such that $$\\beta(K_{1}\\times_{c} K_{2}) \\leq \\beta(K_{1}) + \\beta(K_{2}) - 1$$ In this paper, we define the generalized Conway prod...

  2. Optimum selection on bridge erection with floating crane in East China Sea Bridge and Hangzhou Bay Bridge

    Institute of Scientific and Technical Information of China (English)

    Shunquan Qin; Pu Zhou; Youheng Hua

    2004-01-01

    @@ Introduction With the rapid development of China′s economy, many bridges will be built over the Chinese coastal waters of Pacific Ocean. Among them, construction of East China Sea Bridge has been commenced in June 2001, and will be completed at the end of 2005, Hangzhou Bay Bridge was also started to construct in June 2003(Fig. 1). These two ultralong bridges are designed as twin expressway bridges standing side by side each carries a 3-lane one-way carriageway. The total width is 31.5m and 33.0m respectively. East China Sea Bridge starts from Nanhui District, Shanghai and extends to the Yangshan Deep Water Port Area, which is located at one of the Qiqu Islands. The total length of the bridge is about 31.0 km, in which 25 km are on the sea, and 22 km is in the unnavigable region. Hangzhou Bay Bridge across the mouth of Qiantang River.

  3. 沉湖汉江特大桥主桥连续刚构施工技术%Construction Techniques for Continuous Rigid Frame of Main Bridge of Chenhu Hanjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    赵天元

    2012-01-01

    The main bridge of Chenhu Hanjiang River Bridge is a continuous rigid frame bridge with span arrangement (102 + 168 + 102) m. The superstructure of the bridge is the single-cell single-box girder with variable depth and variable section and the substructure has round en-ded thin-wall twin piers supported on bored pile foundations. The holes of the bored piles for the main bridge were bored by the rotary boring machines and the pile caps were constructed in the steel sheet pile cofferdams. The segments No. 0 of the superstructure were constructed on the scaffolding while the rest of the segments were cantileveredly cast in situ by the diamond-shape form travelers. At the closure gap at the central span, the 4 000 kN horizontal pushing force was applied to fulfill the closure of the span. To ensure the construction quality and safety and to keep the actual status of the bridge to approach the design status to the maximum extent, the closure precision of the closure gap was made to accord with the requirements in the codes and the geometric shape of the completed bridge was made to meet the design status through the construction monitoring and control.%沉湖汉江特大桥主桥为(102+168+102)m连续刚构桥,上部结构为单箱单室、变高度、变截面梁,下部结构采用双墩薄壁圆端形桥墩、钻孔灌注桩基础.主桥桩基采用旋转钻机成孔,承台采用钢板桩围堰法施工;上部结构0号块采用落地式支架法施工,其余节段采用菱形挂篮悬臂浇筑施工,在中跨合龙口设置4 000 kN的水平顶推力,完成中跨合龙.为了保证施工质量及安全,使该桥的实际状态最大限度地趋近设计状态,通过施工监控,使中跨合龙口精度满足规范要求、成桥线形与设计吻合.

  4. Is myocardial bridging a bridge connecting to cardiovascular events?

    Institute of Scientific and Technical Information of China (English)

    LI Jian-jun

    2010-01-01

    @@ Coronary arteries and their major branches usually course on the surface of the heart in the subepicardial tissue. However, a muscle hber overlying the intramyocardial segment of an epicardial coronary artery was defined as myocardial bridging (MB), and subsequently the artery coursing within the myocardium is called a tunneled artery.

  5. Seismic vulnerability analysis of regular continuous girder bridges%规则连续梁桥地震易损性研究

    Institute of Scientific and Technical Information of China (English)

    张菊辉; 管仲国

    2014-01-01

    Structural performance indices for regular continuous girder bridges under different damage states were discussed based on the displacement ductility ratio.On the OpenSees platform,a structural dynamic analysis model was established by using nonlinear fiber beam elements.100 earthquake ground motion records were selected,and the nonlinear time-history analysis was performed,thus the fragility curves under different damage states were constructed. Through parametric analysis,the effects of pier height,bearing types and transverse reinforcement ratios on the fragility curves were studied.The results show that the development degree of ductility of the continuous bridge has a great effect on the structural seismic vulnerability.The fragility curves obtained under minor damage and moderate damage seem to be very close;while under extensive damage,the bridge shows a good performance against earthquake forces.With the increase of pier height,the lower level of damage probability of the structure is observed;meanwhile,the improvement in the fragility by using the plate rubber bearings is excellent for a short-pier bridge,but very limited for a high-pier one. The effect of increasing the transverse reinforcement ratio on fragility curves can be neglected for structural damage in early stage,but it can significantly increase the structural capacity from collapse.%基于位移延性比探讨规则连续梁桥在不同损伤状态下的结构性能控制指标;基于OpenSees平台采用纤维模型建立结构动力分析模型,选取100条强震记录通过非线性时程反应分析计算结构地震易损性曲线。研究不同墩高、支座形式及配箍率对结构地震易损性影响,结果表明,连续梁桥的地震易损性受延性发育程度影响较大,发生中等与轻微破坏概率较相近,对严重破坏有较好的耐损性;结构耐损性随墩高的增大而增加;采用板式橡胶支座可显著提高矮墩桥梁的耐损性,对

  6. 南广铁路西江桥位、桥式方案的选择%Selection of the Site and Type of Xijiang River Bridge on Nanning-Guangzhou Railway

    Institute of Scientific and Technical Information of China (English)

    陈达建

    2011-01-01

    为了使南广铁路以较经济合理的桥位、桥式跨越西江,并满足国家内河Ⅱ级通航等级要求,对适合设桥的小湘河段和三榕峡河段两桥位根据水文地质、通航条件、桥墩防撞设置、施工难易程度等方面进行比选.小湘河段桥位设计桥式为1跨450 m钢箱拱桥,三榕峡河段桥位设计桥式为连续钢桁粱斜拉桥.比较结论为:南广铁路宜在肇庆市内小湘河段跨越西江,设计为1跨过江的450 m钢箱提篮拱桥,提篮拱采用缆索吊机分段吊装.%In order to find out economic and rational bridge site and type for Nanning-Guangzhou Railway to traverse Xijiang river and to satisfy the II class nevigation requirements of domestic rivers, comparative selection has been carried out between two suitable bridge sites; Xiaoxiang river section and Sanrongxia river section, in terms of hydrogeology, nevigation condition, impact-protection installation of piers, construction feasibility, etc. Bridge type of Xiaoxiang site will be a simple span 450 m steel box arch bridge, bridge type of Sanrongxia site will be continuous steel truss cable stayed bridge. It has been concluded that, Naning-Guangzhou railway is recommended to traverse Xijiang river at Xiaoxiang river section in Zhaoqin city, the designed bridge will be a 450 m steel box basket arch bridge, the basket arch will be erected by cable crane by sections.

  7. 3D NUMERICAL SIMULATION ON WATER AND AIR TWO-PHASE FLOWS OF THE STEPS AND FLARING GATE PIER

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ting; WU Chao; LIAO Hua-sheng; HU Yao-hua

    2005-01-01

    A new-style flood discharging dam, which consolidates the flaring gate pier and the stepped spillway for discharging the flood through the dam surface, had been applied in China. The theoretical study on it is in a beginning stage at present. The three-dimensional numerical simulation has not been reported. In this paper, the 3D numerical calculation on the two-phase flow of water and air with discharge per unit width 195m3/s* m is presented . The results indicate that there is negative pressure on the juncture of the spillway surface and the first step. There forms obvious longitudinal and transverse eddies on the steps and the velocity decreases obviously compared with the smooth spillway. The figures of the velocity distributions and the water-air two-phase flows are plotted. The results calculated on the pressure are in agreement with the experimental data. Based on the position of the negative pressure obtained from calculation, measurement points of pressure are arranged in physical model. The experimental results validate the existence of the negative pressure. Being an applied and trial study, the results obtained are of theoretical and practical significance.

  8. 高烈度区连续梁桥减震的粘滞阻尼器参数分析%Parametric analysis of viscous dampers for earthquake mitigation of continuous bridges in high intensity region

    Institute of Scientific and Technical Information of China (English)

    邓稳平; 王浩; 李爱群; 柳建设

    2012-01-01

    连续梁桥应用广泛,其损害占据桥梁工程地震灾害中的重要部分,有必要对连续梁桥进行专门的抗震设计,而安装粘滞阻尼器是改善桥梁结构抗震性能的有效手段之一.以位于地震高烈度区的太白大桥为例,通过有限元计算研究了设置粘滞阻尼器对预应力混凝土连续梁桥地震响应的影响,并重点针对阻尼器的阻尼系数和速度指数进行参数分析.结果表明:设置阻尼器后,固定墩墩底弯矩、边墩主梁相对位移都显著减小;各墩受力更趋均匀;阻尼器阻尼力随阻尼系数C增大而增大,随速度指数α增大而减小.所得结论可供高烈度区连续梁桥的减震设计参考.%Installing viscous dampers is one of the effective measures to improve the seismic performance of continuous bridges. Taking the Taibai Bridge located in high-intensity seismic zone as an example, the influence of viscous dampers on seismic responses of a prestressed concrete continuous bridge was investigated, and the parametric analyses of the damping coefficient and velocity exponent were carried out. Results show that both the bending moment at the bottom of the fixed pier and the longitudinal relative displacement between the main girder and the side pier are significantly reduced when the viscous dampers have been installed. Moreover, the seismic forces on the piers become more evenly distributed. The damping forces of the dampers increase with the increase of damping coefficient, and decrease with the increase of velocity exponent. The results can provide reference to seismic design of continuous bridges in high intensity region.

  9. Architectural engineering of FRP bridges

    OpenAIRE

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on architectural application of FRP's derived from the authors architectural practice.

  10. Instability of the capillary bridge

    Science.gov (United States)

    Pare, Gounseti; Hoepffner, Jerome

    2014-11-01

    Capillary adhesion is a physical mechanism that maintains two bodies in contact by capillarity through a liquid ligament. The capillary bridge is an idealization of this capillary adhesion. In this study we first focus on the classical case of the stability of the capillary bridge. Secondly we study a slightly more complex configuration, imagining a flow in the capillary bridge as in the case of the dynamics of the neck of a liquid ligament, in its withdrawal under the effect of capillarity. Inspired by the experiments on soap films of Plateau, the configuration analyzed consists of an initially axisymmetric, mass of fluid held by surface tension forces between two parallel, coaxial, solid pipes of the same diameter. The results presented are obtained by numerical simulations using the free software, Gerris Flow Solver. We first focus on the capillary Venturi. In the static configuration the stability diagram of the capillary bridge obtained is in perfect agreement with the results of Lev A. Slobozhanin. In the dynamic case we develop a matlab code based on the one dimensional equations of Eggers and Dupont. The comparison of the bifurcation diagram obtained and the numerical simulations shows a good agreement.

  11. Bridge Aesthetics and Structural Honesty

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    In bridges the overall form must be chosen with due respect to the transmission of forces if efficient structures shall be created, The design must therefore be governed by experienced structural engineers - in some cases assisted by aesthetic advisers on specific issues. Some basic requirements...

  12. The Wien Bridge Oscillator Family

    DEFF Research Database (Denmark)

    Lindberg, Erik

    2006-01-01

    A tutorial in which the Wien bridge family of oscillators is defined and investigated. Oscillators which do not fit into the Barkhausen criterion topology may be designed. A design procedure based on initial complex pole quality factor is reported. The dynamic transfer characteristic...

  13. Architectural engineering of FRP bridges

    NARCIS (Netherlands)

    Smits, J.E.P.

    2014-01-01

    This paper deals with the use of Fibre Reinforced Polymers (FRP's) in architectural and structural bridge design. The challenges and opportunities that come with this relatively new material are discussed. An inventory is made of recent engineers' solutions in FRP, followed by a discussion on archit

  14. Intercellular bridges in vertebrate gastrulation.

    Directory of Open Access Journals (Sweden)

    Luca Caneparo

    Full Text Available The developing zebrafish embryo has been the subject of many studies of regional patterning, stereotypical cell movements and changes in cell shape. To better study the morphological features of cells during gastrulation, we generated mosaic embryos expressing membrane attached Dendra2 to highlight cellular boundaries. We find that intercellular bridges join a significant fraction of epiblast cells in the zebrafish embryo, reaching several cell diameters in length and spanning across different regions of the developing embryos. These intercellular bridges are distinct from the cellular protrusions previously reported as extending from hypoblast cells (1-2 cellular diameters in length or epiblast cells (which were shorter. Most of the intercellular bridges were formed at pre-gastrula stages by the daughters of a dividing cell maintaining a membrane tether as they move apart after mitosis. These intercellular bridges persist during gastrulation and can mediate the transfer of proteins between distant cells. These findings reveal a surprising feature of the cellular landscape in zebrafish embryos and open new possibilities for cell-cell communication during gastrulation, with implications for modeling, cellular mechanics, and morphogenetic signaling.

  15. Dynamic identification of paradela historic railway bridge

    OpenAIRE

    Ramos, Luís F.; Valente, Isabel; Guimarães, Paulo; Vazquez, Kevin; Lourenço, Paulo B.

    2013-01-01

    Paradela Bridge is a metallic bridge located along the bank of the Tua River in northern Portugal. While the bridge is not currently in service, its structure is representative of many metallic truss structures built across the country between the 19th and the 20th century. The construction of the Paradela Bridge was completed in 1886 and served for about 120 years connecting northern Portugal. Tua Line belongs to the Douro area that UNESCO recently declared as world heritage. This work acqui...

  16. Transition Slabs of Integral Abutment Bridges

    OpenAIRE

    Dreier, Damien; Muttoni, Aurelio; BURDET, Olivier

    2011-01-01

    Over the past decades, an increasing number of bridges with integral abutment have been built in Switzerland. This type of bridge offers various advantages over standard bridges with abutments, equipped with expansion joints and bearings that require regular inspection and maintenance. One main concern of integral abutment bridges is related to the soil-structure interaction, in particular between the transition slab and the embankment. To avoid any expansion joints, transition slabs are dire...

  17. Path transformations of first passage bridges

    OpenAIRE

    Bertoin, Jean

    2003-01-01

    We define the first passage bridge from 0 to $\\lambda$ as the Brownian motion on the time interval $[0,1]$ conditioned to first hit $\\lambda$ at time 1. We show that this process may be related to the Brownian bridge, the Bessel bridge or the Brownian excursion via some path transformations, the main one being an extension of Vervaat's transformation. We also propose an extension of these results to certain bridges with cyclically exchangeable increments.

  18. 47 CFR 80.331 - Bridge-to-bridge communication procedure.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge communication procedure. 80..., Alarm, Urgency and Safety Procedures § 80.331 Bridge-to-bridge communication procedure. (a) Vessels... position). I plan to (give proposed course of action). Over. (3) (Coast station), this is (vessel's...

  19. Removal of failed crown and bridge.

    Science.gov (United States)

    Sharma, Ashu; Rahul, G R; Poduval, Soorya T; Shetty, Karunakar

    2012-07-01

    Crown and bridge have life span of many years but they fail for a number of reasons. Over the years, many devices have been designed to remove crowns and bridges from abutment teeth. While the removal of temporary crowns and bridges is usually very straightforward, the removal of a definitive cast crown with unknown cement is more challenging. Removal is often by destructive means. There are a number of circumstances, however, in which conservative disassembly would aid the practitioner in completing restorative/endodontic procedures. There are different mechanisms available to remove a failed crown or bridge. But there is no information published about the classification of available systems for crown and bridge removal. So it is logical to classify these systems into different groups which can help a clinician in choosing a particular type of system depending upon the clinical situation. The aim of this article is to provide a classification for various crown and bridge removal systems; describe how a number of systems work; and when and why they might be used. A PubMed search of English literature was conducted up to January 2010 using the terms: Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. Additionally, the bibliographies of 3 previous reviews, their cross references as well as articles published in various journals like International Endodontic Journal, Journal of Endodontics and were manually searched. Key words:Crown and bridge removal, Crown and bridge disassembly, Crown and bridge failure. PMID:24558549

  20. Remediation: Higher Education's Bridge to Nowhere

    Science.gov (United States)

    Complete College America, 2012

    2012-01-01

    The intentions were noble. It was hoped that remediation programs would be an academic bridge from poor high school preparation to college readiness. Sadly, remediation has become instead higher education's "Bridge to Nowhere." This broken remedial bridge is travelled by some 1.7 million beginning students each year, most of whom will…

  1. 基于性能的中小跨径装配式梁桥地震易损性分析%Fragility analysis for performance-based seismic design of prefabricated bridge with middle-small span

    Institute of Scientific and Technical Information of China (English)

    张云; 谭平; 郑建勋; 周福霖

    2014-01-01

    标准跨径装配式梁桥由于造价低廉,便于设计和施工,在中国公路路网中广泛使用,成为公路网应用最多的桥型结构。虽然使用广泛,但是针对具有这种设计特点桥梁的地震易损性的研究还比较少。本文以典型的多跨梁桥为例,以使用功能作为设防目标定义了桥梁的5种性能水平,提出了详细的桥墩损伤指标界定值作为桥墩4种损伤极限状态界定准则。在此基础上,明确提出了这类桥梁的地震易损性分析方法,考虑了结构本身主要材料的不确定性和地震动输入的不确定性,得到了结构的地震易损性曲线。根据易损性分析结果,探讨了桥梁失效模式和损伤概率,为公路路网抗震能力分析和应急预案的制定提供了理论依据。%The prefabricated bridge with standard span have become the most widely used structure in the highway-net by ad-vantage of its low cost ,simple design and construction .However ,study on seismic fragility of such bridges is rarely found yet .Taking service function as seismic fortification goal ,this paper defines five levels of performance for typical multi-span bridges .The critical damage value for the bridge pier is put forward as the criteria of four kinds of pier damage limit states . Moreover ,the method and procedure of seismic fragility analysis of highway bridges are presented ,in which uncertainties of the primary structure materials and ground motion input are considered respectively .The seismic fragility analysis is conducted to obtain the bridge failure mode and damage probability .The fragility analysis for performance-based seismic design of high-way bridges provides the theoretical basis for a seismic performance analysis and emergency preplan formulation in the high-w ay-net .

  2. Comparison between Modern Violin Bridge and Baroque Violin Bridge by Photoelastic Observation and Frequency Analysis

    Science.gov (United States)

    Matsutani, Akihiro

    2004-05-01

    A comparison between the modern bridge and the baroque bridge of the violin by photoelastic observation was carried out. The relationship between the stress part and the hole is symmetric in the modern and baroque bridges. The measured spectral envelopes of baroque bridges are similar to those of modern bridges in D- or G-strings, and have peaks at a frequency higher than those of modern bridges in E-string. The visualization method as used in this study may provide hints for the design of violin bridges.

  3. 三维地震动作用下曲线连续梁桥减震控制研究%Seismic mitigation control for a curved continuous girder bridge with 3-D ground motion action

    Institute of Scientific and Technical Information of China (English)

    亓兴军; 申永刚

    2012-01-01

    In order to reduce seismic damage effect of a curved girder bridge with double supports, the seismic response mitigation control technique with liquid viscous dampers was presented. The spatial finite element model and dynamic simulation model of a curved continuous girder bridge were established, and viscous dampers were set at the kinetic bearings of piers in tangent and radial orientations. Seismic mitigation effectiveness of active control, semi-active control and passive control for the bridge was calculated and analyzed with three-dimensional (3-D) ground motion input. The results indicated that the curved girder bridge has distinct characteristic of seismic coupling between longitudinal and transversal orientations; three orientations of the ground motion must be input simultaneously and longitudinal and transversal dampers are set simultaneously when seismic mitigation responses are calculated; the viscous dampers can control internal forces of inside pier and outside pier to be close to each other; the three mitigation approaches can effectively reduce displacement of girder and internal force of fixed piers of the curved girder bridge; the differences of seismic mitigation effectiveness and seismic response time histories are smaller for the three mitigation approaches; active control and semi-active control have no obvious advantage, and the passive control with viscous dampers can be widely applied in actual seismic design of a curved girder bridge.%为了减少双支承曲线梁桥的地震破坏效应,提出了利用液体粘滞阻尼器进行曲线梁桥减震控制的方法,建立曲线连续梁桥的空间有限元模型和动力仿真模型,在桥梁墩台活动支座部位设置切向和径向液体粘滞减震装置,输入三维地震动计算分析了桥梁主动控制、半主动控制和被动控制三种减震方法的减震效果.结果表明,曲线梁桥的地震反应表现出显著的纵桥向与横桥向的耦合特性,在减震控制

  4. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    OpenAIRE

    Lei Su-su; Gao Yong-tao; Pan Dan-guang

    2015-01-01

    Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and trans...

  5. New Concept for Durable Concrete Bridges

    OpenAIRE

    Damek, Marek

    2015-01-01

    This master’s thesis covers the design of a post-tensioned concrete bridge in Trondheim municipality in Norway, in collaboration with Statens vegvesen (SVV). The concept of the bridge is inspired by Egg-Graben-Brücke in Austria, which was designed and built without steel reinforcement in the bridge deck. The idea is to eliminate steel reinforcement which can corrode in the bridge deck. The total length of the bridge is 73 meters and it is divided into 3 spans. The crosssection ...

  6. Seismic response analysis of high-speed vehicle-bridge considering soil-structure interaction%考虑桩-土作用的高速列车-桥梁地震响应分析

    Institute of Scientific and Technical Information of China (English)

    陈令坤; 蒋丽忠; 陶磊; 余志武

    2012-01-01

    Based on the finite beam element method, two kinds of whole bridge models of high-speed railway multi-span simply-supported bridge are set up. One is vehicle-bridge model including pile foundation, the dynamic impedances of the layered soil are presented, the improved Penzien model is used to simulate the soil-structure interaction (SSI); the other is vehicle-bridge model where pier bottom is consolidated without considering SSI; the seismic responses of the models are computed at different vehicle speeds, pier heights, earthquake strengths and earthquake waves. The calculation results show that the influence of the SSI on seismic responses of high-speed vehicle-bridge on soft foundation can not be ignored; the lateral displacement and acceleration of the bridge are influenced by low-frequency components, those low-frequency components interact with the earthquake wave incident from bottom side of the piles, which change the spectrum composition of the foundation movement, the frequency components which approach to bridge vibration frequency are strengthened; the lateral displacement and acceleration of bridge increase a lot after considering SSI; the vertical vibration frequency of the bridge changes little while considering SSI; the vertical displacement of the boxing girder increases little with the increase of pier height and vehicle speed; the high-frequency components which are caused mainly by the vehicle load and the track irregularity significantly influenced on the vertical acceleration of the boxing girder.%基于空间梁单元有限元法,建立了两种高速铁路多跨简支梁桥的全桥空间分析模型,一种是包括桩基的列车-桥梁模型,给出成层土的动力阻抗,采用改进的Penzien模型模拟桩-土作用;一种是不考虑桩-土作用的墩底固结的列车-桥梁模型;分析了两种模型的自振特性,计算了两种模型在不同车速、墩高、地震强度、不同地震波等工况下的地震反应.计算

  7. Construction Techniques for Long Cantilever Capping Beam of In-Water Portal Pier of Lanni Lake Viaduct%烂泥湖高架桥水中门式墩长悬臂盖梁施工技术

    Institute of Scientific and Technical Information of China (English)

    钟庆荣; 杨贵龙; 胡洪波; 张建春

    2012-01-01

    烂泥湖高架桥水中门式墩预应力盖梁悬臂长5.975 m,为确保盖梁施工顺利进行,在分析抱箍法(钢梢棒法)和钢管桩支架法的支架受力、悬臂端挠度后,确定采用钢管桩支架法施工盖梁.支架下部采用φ630 mm钢管桩,在钢管桩上搭设双排I45a工字钢作为分配梁,分配梁横桥向上铺设2组贝雷梁,贝雷梁顺桥向上铺设I20a工字钢,在盖梁翼缘及中部拱形横梁下方搭设碗扣式脚手架并设置剪刀撑及扫地杆,脚手架顺桥向顶撑上铺设10 cm×15 cm方木,以支承盖梁模板;支架搭设完后安装盖梁模板,加工钢筋,浇筑盖梁混凝土.分析表明,钢管桩支架法能保证长悬臂盖梁端部挠度变形不影响盖梁线形及断面尺寸,确保长悬臂盖梁施工质量及安全.%The cantilever length of a prestressed concrete capping beam of the in-water portal pier of Lanni Lake Viaduct is 5. 975 m. To ensure the smooth construction of the capping beam and after analysis of the force conditions and cantilever end deflection of the girdling method (steel tip staff method) and the steel pipe pile scaffolding method, it was determined that the steel pipe pile scaffolding method should be used for construction of the capping beam. For the lower part of the steel pipe pile scaffolding, the 0630 mm steel pipe piles were used. On the pipes, the double-row I45a I-steels were laid to serve as the distribution beam. On the distribution beam in the transverse direction of the bridge, 2 groups of the bailey trusses were laid and on the bailey trusses in the longitudinal direction of the bridge, the I20a I-steels were laid. On the flanges of the capping beam and under the middle arch crossing beam, the bowl-coupler scaffolding was set up, on which the cross struts and floor horizontal members were installed. On the top supports of the scaffolding in the longitudinal direction of the Bridge, the square timbers of 10 cmX 15 cm were laid to support the formwork of

  8. 大跨度桥梁荷载试验结构变形测试与分析%Structure Test and Analysis of Bridge Load Test Results of Deformation of Large Span Bridge

    Institute of Scientific and Technical Information of China (English)

    毕雨田

    2016-01-01

    How to ensure the safety performance of existing bridges is a problem that researchers face. Bridge static load test is an effective method for safety evaluation of existing bridges.Static load test of a 5 span continuous box girder bridge is carried out by using finite element software to establish a numerical simulation model of full bridge,the bridge deflection values of L/2 and L/4 cross sections under the working condition of 2-3 and 3-4 span loading are respectively analyzed,and the bending moment value of No.4 pier under top load is negative.After testing,the maximum deflection of the mid-span section is 11.1 mm,and the calculated value is 11.5 mm.The deflection values of 3 kinds of load conditions are compared and analyzed,and the results show that the measured values are in good agreement with the theoretical calculated values.%采用桥梁静载试验是对在役桥梁安全评价的有效方法。文中通过对某5跨连续箱梁桥进行静荷载试验,利用有限元软件建立全桥数值仿真模型,分别分析该桥在2~3跨、3~4跨时L/2截面和 L/4截面的挠度值;4号墩墩顶荷载下负弯矩值。经过测试,该桥在跨中截面最大的挠度值为11.1 mm,而计算值为11.5 mm。对3种荷载工况下的挠度值进行对比分析,得出该桥的实测值和理论计算值吻合较好,表明该桥具有足够的桥梁安全储备。

  9. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    Vibration of a bridge structure due to the passage of vehicles is an important consideration in the design of bridges. Further, a common problem in bridge engineering practice in these years is the upgrading of minor highway bridges (=5-20 m) to carry heavier loads partly due to a tendency...... of heavier trucks moving at larger speeds, and partly because the authorities want to permit transportation of special heavy goods at a larger part of the road net. These needs will in many cases cause the strengthening of the bridges becomes necessary. In order to keep the expenses of such strengthening...... the results obtained using the numerical models given in details in "Heavy Vehicles on Minor Highway Bridges : dynamic modelling of vehicles and bridges". The models are established using a ordinary vehicle which consists of a 48 t Scania with a 3 axle tractor and a 3 axle trailer, joined in a flexible hinge...

  10. Heavy Vehicles on Minor Highway Bridges

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Nielsen, Søren R. K.; Enevoldsen, I.

    Vibration of a bridge structure due to the passage of vehicles is an important consideration in the design of bridges. Further, a common problem in bridge engineering practice in these years is the upgrading of minor highway bridges (=5-20 m) to carry heavier loads partly due to a tendency...... of heavier trucks moving at larger speeds, and partly because the authorities want to permit transportation of special heavy goods at a larger part of the road net. These needs will in many cases cause the strengthening of the bridges becomes necessary. In order to keep the expenses of such strengthening...... the numerical models for the mathematical models of the vehicles and the bridge from which the load amplification factors can be estimated assuming that the dynamic parameters of the vehicles and the modal parameters of the bridge are known....

  11. Full-bridge capacitive extensometer

    Science.gov (United States)

    Peters, Randall D.

    1993-08-01

    Capacitive transducers have proven to be very effective sensors of small displacements, because of inherent stability and noninvasive high resolution. The most versatile ones have been those of a differential type, in which two elements are altered in opposite directions in response to change of the system parameter being monitored. Oftentimes, this differential pair has been incorporated into a bridge circuit, which is a useful means for employing synchronous detection to improve signal to noise ratios. Unlike previous differential capacitive dilatometers which used only two active capacitors, the present sensor is a full-bridge type, which is well suited to measuring low-level thermal expansions. This analog sensor is capable of 0.1 μm resolution anywhere within a range of several centimeters, with a linearity of 0.1%. Its user friendly output can be put on a strip chart recorder or directed to a computer for sophisticated data analysis.

  12. Noise Considerations in Resistance Bridges

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1963-01-01

    thermometry, where the noise in the unknown resistor will predominate strongly. An impedance step-up device (transformer or tuned circuit) is valuable in raising the bridge signal and noise level above the noise of the first amplifier tube. However, as the step-up ratio is increased, two counterfactors appear......, namely, noise in the loss resistance of the step-up device, and grid current noise. There is therefore an optimum step-up ratio, which has been found. The step-up device is permitted to have a different temperature from the unknown and standard resistors, to evaluate the advantage of cooling it....... With certain assumptions about the noise and grid current of the first tube it is found that the equivalent temperature of a unity ratio (Mueller) bridge used for liquid helium measurements may be 400°K....

  13. Stability of Axisymmetric Liquid Bridges

    CERN Document Server

    Rubinstein, Boris

    2016-01-01

    We study stability of axisymmetric liquid bridges between two axisymmetric solid bodies in the absence of gravity under arbitrary asymmetric perturbations which are expanded into a set of angular Fourier modes. We determine the stability region boundary for every angular mode in case of both fixed and free contact lines. Application of this approach allows us to demonstrate existence of stable convex nodoid menisci between two spheres.

  14. 2015 Bridge Inspection ERC Training

    OpenAIRE

    Dougherty, Merril

    2015-01-01

    This presentation will discuss recent changes to the County Bridge Inspection Program from the perspective of both the FHWA and INDOT. We will also discuss the responsibilities of the local public agency’s (LPA’s) employee in responsible charge (ERC) with respect to managing this program. As this course is a yearly requirement, all county ERCs are encouraged to attend. Pre-registering is strongly encouraged by e-mailing your contact information to .

  15. The Bridge Program - Participant Perspectives

    OpenAIRE

    Rönnqvist, Riitta; Hakonen, Anu; Vartiainen, Matti

    2015-01-01

    The Nokia Bridge Program was established in summer 2011 in order to "make the best of the restructuring: create meaningful opportunities for individuals and local economies impacted by workforce reductions" and to "assist individuals in re-employment". This document reports whether and how the program helped individuals avoid the known negative effects of job loss and find meaningful re-employment. The document also reports how affected employees formed perceptions about Nokia´s fairness and ...

  16. Inspection Strategies for Concrete Bridges

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Thoft-Christensen, Palle

    1989-01-01

    In this paper an optimal inspection strategy for concrete bridges based on periodic routine and detailed inspections is presented. The failure mode considered is corrosion of the reinforcement due to chlorides. A simple modelling of the corrosion and of the inspection strategy is presented....... The optimal inspection strategy is determined from an optimization problem, where the design variables are time intervals between detailed inspections and the concrete cover. The strategy is illustrated on a simple structure, namely a reinforced concrete beam....

  17. Parabolic metamaterials and Dirac bridges

    Science.gov (United States)

    Colquitt, D. J.; Movchan, N. V.; Movchan, A. B.

    2016-10-01

    A new class of multi-scale structures, referred to as `parabolic metamaterials' is introduced and studied in this paper. For an elastic two-dimensional triangular lattice, we identify dynamic regimes, which corresponds to so-called `Dirac Bridges' on the dispersion surfaces. Such regimes lead to a highly localised and focussed unidirectional beam when the lattice is excited. We also show that the flexural rigidities of elastic ligaments are essential in establishing the `parabolic metamaterial' regimes.

  18. Severe ASR damaged concrete bridges

    DEFF Research Database (Denmark)

    Antonio Barbosa, Ricardo; Gustenhoff Hansen, Søren

    2015-01-01

    Technical University of Denmark (DTU) and University of Southern Denmark (SDU) have conducted several full-scale experiments with severe ASR deteriorated bridges. This paper presents few and preliminary results from both the shear tests and the measuring of the material properties. The shear test...... show that the shear capacity is almost unaffected of ASR despite significant reduction in compressive concrete strength. Furthermore, measurements show a significant tensile reinforcement strain developed due to ASR expansion....

  19. Halliburton Composite Bridge Plug Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Starbuck, J.M.; Luttrell, C.R.; Aramayo, G.

    2005-01-15

    The overall objectives of this CRADA were to assist Halliburton in analyzing a composite bridge plug and to determine why their original design was failing in the field. In Phase 1, finite element analyses were done on the original composite slip design and several alternative designs. The composite slip was the component in the bridge plug that was failing. The finite element code ABAQUS was used for these calculations and I-DEAS was used as the pre- and post-processor in the analyses. Several different designs and materials were analyzed and recommendations were made towards improving the design. In Phase 2, the objective was to develop finite element models that would accurately represent the deformations in the entire all-composite 4-1/2' diameter bridge plug assembly. The finite element code LS-DYNA was used and the results from this effort were intended to expand Halliburton's composite design and analysis capabilities with regard to developing future composite components for downhole tools. In addition to the finite element modeling, this effort involved the utilization of micromechanics to determine the necessary composite material properties that were needed as input for finite element codes.

  20. Structure recheck and reinforcement of pier of spillway tunnel of Lishimen reservoir%里石门水库泄洪孔闸墩结构复核及加固

    Institute of Scientific and Technical Information of China (English)

    胡士兵; 谢霄易; 何雷霆

    2009-01-01

    Based on the results of structure recheck of pier of spillway tunnel at Lishimen reservoir by finite element method, this paper pointed out that the fan steel bar of pier was too short to meet the safety requirement and advanced how to reinforce pier by carbon fiber. Further, the key points in construction of carbon fiber was described.%采用有限元方法对里石门水库泄洪孔出口闸墩进行了结构复核,指出了闸墩扇形钢筋长度不足的缺陷,提出碳纤维加固方案,并阐述了碳纤维加固施工要点.

  1. 郑州市解放路跨线桥主桥设计与施工%Design and Construction of Main Bridge of Jiefang Road Overpass Bridge in Zhengzhou City

    Institute of Scientific and Technical Information of China (English)

    申国朝

    2012-01-01

    The main bridge of the Jiefang Road Overpass Bridge in Zhengzhou City is a cable-stayed bridge with twin pylons, single cable plane and with span arrangement (106 + 248 + 106) m and the bridge employs the structural system of rigid fixity of its pylons and main girder. The main girder of the bridge is of the prestressed concrete triple-cell single box of quasi-triangle section and has a 62 m long variable width portion at the side span on the west side. On both sides of a pylon, 15 pairs of stay cables made up of the low relaxation and high-strength galvanized parallel steel wires are arranged. The pylons are the concrete solid single-column ones of H-shape sections and the main piers are the vase shape hollow reinforced concrete structures supported on the frictional group bored pile foundations. The software Bridge Doctor V3. 03, MIDAS Civil and ANSYS were used to respectively build the plane finite element model for the bridge and the plane link and spatial plate-shell finite element models for the variable width portion. With these models, the global static force of the bridge and the force conditions of the portion were analyzed. In addition, a 1: 4 model for the variable width portion was also designed and made to carry out the model test. The results of the finite element analysis and model test showed that the force conditions of various parts of the bridge could meet the requirements in the codes. The part of the bridge spanning the passenger dedicated railway line on the east side was constructed by the rotation erection while the part of the bridge spanning the freight railway line on the west side was constructed by the covered form traveler.%郑州市解放路跨线桥主桥为双塔单索面斜拉桥,跨径布置为(106+248+106)m,采用塔、梁固结体系.该桥主梁为预应力混凝土单箱三室准三角形截面,西侧边跨设62 m长的变宽段.每个桥塔两侧布置15对斜拉索,斜拉索采用低松弛镀锌高强平行钢丝.桥塔采

  2. Application of Double Hoop Technique in Single Pier Construction%双抱箍技术在独墩施工中的应用

    Institute of Scientific and Technical Information of China (English)

    许广利

    2014-01-01

    本文通过双抱箍施工技术在青岛蓝色硅谷交通轨道工程盖梁施工中的实际应用,探索出了一条单墩独柱盖梁施工的安全可靠、经济可行的施工方法。%Through the practical application of double hoop construction technology in Qingdao blue silicon valley traffic track engineering capping beam construction, this article explores a safe and economic construction method for single pier column cap beam construction.

  3. To study the problem of excessive loading efficiency by using the bridge finite element software%采用有限元软件研究桥梁加载效率超限的问题

    Institute of Scientific and Technical Information of China (English)

    周琳琳; 贾海浩

    2015-01-01

    In order to research on the problem of unequal loading efficiency over bridge test section, Using the finite element software MIDAS/CILVAL、Dr.Bridge, choose continuous beam of three large span, span the gap and loading of a test sec-tion, and calculate the loading efficiency, Come to the conclusion that the side span maximum positive moment is not in the 0.4L position and with increasing bridge spans other major test section loading efficiency exceeded problems become appar-ent when in the test section of bridge pier top.%为了研究不等跨桥梁测试截面的加载效率超限问题,采用有限元软件MIDAS/CILVAL、桥梁博士,选择三种边跨、中跨跨径差距较大的连续梁并对其主要测试截面进行加载,并计算出加载效率,得出边跨最大正弯矩并不在0.4 L位置处及随着桥梁跨径增大,在测试墩顶断面时桥梁其他主要测试截面加载效率超限问题趋于明显的结论。

  4. 沪蓉高速公路铁罗坪大桥设计%Design of Tieluoping Bridge on Shanghai-Chengdu Expressway

    Institute of Scientific and Technical Information of China (English)

    郭安辉; 张门哲

    2012-01-01

    铁罗坪大桥主桥为预应力混凝土双塔双索面斜拉桥,跨径布置为(140+322+140)m.该桥主梁基本断面形式为边主梁;桥塔为H形,总高190.397 m,塔柱采用空心五边形断面,在上塔柱锚固区采用U形预应力束加强,桥塔墩基础由24根φ2.4m的桩基组成;每个桥塔两侧布置19对斜拉索,斜拉索采用低松弛镀锌高强钢丝.从温度作用、汽车荷载作用、成桥阶段稳定系数方面对2种结构体系(墩塔梁固结体系和飘浮体系)进行比选,最终选择了对结构受力更为有利的墩塔梁固结体系.采用MIDAS Civil软件分别对该桥静、动力特性、抗风稳定性及地震反应进行分析,分析结果表明结构受力均满足规范要求.该桥主梁采用悬臂浇筑施工,合龙顺序为先边跨、再中跨.%The main bridge of the Tieluoping Bridge on Shanghai-Chengdu Expressway is a prestressed concrete cable-stayed bridge with double pylons, double cable planes and with span arrangement (140 + 322 + 140) m. The basic section of the main girder of the bridge is the section of edge main girders and the pylons are the H-shape ones, each being 190. 397 m in total height. The columns of a pylon were designed as the hollow pentagonal sections and in the anchorage zones in the upper parts of the columns, the U-shape prestressing strands were employed to reinforce the zones. A foundation for the pylon piers is composed of 24 nos. of f2. 4 m piles. On both sides of a pylon, 19 pairs of stay cables, made up of the low relaxation and high-strength galvanized steel wires, were arranged. Two kinds of the structural systems of the rigid fixity system of pier, pylon and girder and the floating system were compared from aspects of the temperature action, truck load action and stability coefficients of the completed bridge and eventually, the rigid fixity system that is more advantageous to the structural force conditions of the bridge was chosen. The software MIDAS Civil was

  5. 论侵权行为地法原则%Discussion of Security Management in the Jiashao Bridge Project

    Institute of Scientific and Technical Information of China (English)

    宋环环; 周静

    2012-01-01

    The V Project of Jiashao Bridge is characterized by the abominable natural conditions, complex hydrology conditions, numerous construction machineries , especially many heavy and temporary facilities, bridge pier construction with high altitude works and near water works as well as main trestle bridge is long and high frequency of utilization and so forth. Considering the establishment of secure regulation management system, the implementation of security responsibility, the safety pro- duction input and the security risks mortgage systems, the safety explanations and related educational training, on -site safety management, safety inspection and the hidden danger rectification, the paper discussed the prevention of major source of danger, the safety management tbrms and the satety project culture.%侵权行为地法原则是国际侵权法领域最古老的准据法原则之一。如今,国际交往日益频繁,涉外法律冲突频现。现实中,侵权行为地法原则遭遇了种种挑战,在理论基础、行为地的识别等方面均受质疑。因此,有必要在回顾传统侵权行为地法原则适用的基础上,从理论与实践的角度结合比较分析法探究侵权行为地法原则的现代意义与取舍。

  6. 采动影响下三连铁路桥维修加固方案%Maintenance and Reinforcement Schemes of Sanlian Railway Bridge Under the Influence of Mining

    Institute of Scientific and Technical Information of China (English)

    田迎斌

    2015-01-01

    为了实现受采动影响铁路桥梁的安全运行,应用概率积分法预计了S2 S7工作面开采对三连铁路桥产生的最大移动与变形值。在此基础上分析了下沉、倾斜及水平变形对桥梁结构的影响。结果表明:桥梁下沉后铁路桥下过水断面净空高度满足规范要求;桥梁纵向倾斜不影响行车,可通过不断调整轨面来满足规范要求的桥梁横向倾斜且不影响墩台的稳定性;桥梁纵向压缩不会影响正常使用,但桥梁基础横向拉伸变形已达Ⅲ级。针对桥梁基础有可能遭受到较大损害的情况,提出了采用扁钢对桥墩及桥台进行加固的设计方案,并提出了保证线路正常运行的安全措施。实践表明,经过加固的铁路桥经受住了S2 S7工作面的采动影响,达到了铁路桥下安全采煤的目的。%In order to realize the safety service of the railway bridge influenced by mining,the probability integral method was used to predict the movement and deformation values of the Sanlian railway bridge at the S2 S7 working face during mining. Based on this,the effect of subsidence,inclination and horizontal deformation on structure of railway bridge was analyzed. The results showed that the wetted cross section height under the railway bridge is in accord with the requirement of criterion,the longitudinal inclination of the bridge beam did not influence the driving,and the horizontal inclination met the requirement of the criterion by adjusting the orbit plane,so it cannot influence the stability of the bridge pier. The longitudinal compression of the bridge did not affect the use, but the tensile deformation of the bridge lateral basis reached Class III, resulting that the bridge foundation may suffer the great damage. In view of this,the design which adopted the flat steel to strengthen the bridge pier and abutment was proposed,and the safety measures for the normal service of the bridge were put forward. The

  7. 对连续梁桥减隔震支座抗震性能的比较分析%Seismic Isolation Bearing On the Comparative Analysis of the Seismic Performance for Continuous Beam Bridge

    Institute of Scientific and Technical Information of China (English)

    史康; 全健; 王福敏; 耿波

    2014-01-01

    以厦漳跨海大桥北汊南引桥为依托,采用有限元非线性时程分析方法,比较分析了铅芯橡胶支座和盆式橡胶支座对高烈度地区大跨径连续箱梁桥的抗震影响。研究结果表明:铅芯橡胶支座增加了结构在地震作用下的振动周期和主梁梁端位移,减小了固定墩的受力。相比盆式橡胶支座,铅芯橡胶支座可以使主梁梁端位移增加20%~200%,固定墩内力减小36%~80%。说明铅芯橡胶支座能够通过增加主梁位移达到减小桥墩受力的效果,隔震效果明显。该研究成果可为同类型桥梁的抗震设计提供参考。%Based on north south approach spans of Xiamen -zhangzhou cross-sea bridge by using the finite element nonlinear a-nalysis method, the seismic impact is compared between lead -rubber bearing and pot rubber bearing on the long span box girder bridges in high-intensity areas .The results show that the lead -rubber bearing can increase the vibration period and displacement of main beam in earthquake , reduce the force of fixed piers .Compared with pot rubber bearing , adopting lead-rubber bearing can in-crease the end displacement of main grider by 20%to 200%, meanwhile decrease internal force for fixed piers by 36%to 80%.The isolation effect is obvious that lead -rubber bearings can reduce the pier force by increasing the displacement of main beam .The re-search results provide a reference for the same type of bridge seismic design .

  8. New technological approach in reconstructing Hanshin expressway. Base isolation for continuous rigid frame bridge; Hanshin kosoku doro fukkyu deno aratana kokoromi. Rittai ramen kyokyaku kabu menshinkyo wo chushin to shite

    Energy Technology Data Exchange (ETDEWEB)

    Morikawa, H. [Kobe University, Kobe (Japan). Faculty of Engineering

    1996-09-15

    This paper presents new technological approach in reconstructing Hanshin expressway damaged by Hyogo-ken Nanbu earthquake. The expressway of Benten section was composed of 6 three-span continuous RC floor slab girders supported by RC single columns, and 2 simple girders. Among them, 3 girders fell and 5 girders were largely damaged. As the study result of various structures for reconstruction, the 19-span continuous steel plate deck rigid frame bridge was adopted which is supported by steel piers with plane aseismic base isolation structure first in the world. Static and dynamic analyses of 3-D model were carried out to evaluate structure characteristics. The result of static analysis revealed that pile reaction forces are allowable, and horizontal forces due to earthquake or temperature at the bottom of piers considerably decrease. The result of eigenvalue analysis revealed that all of preferential lower- order modes are horizontal mode, and their frequencies are as low as 0.7Hz. The designed damping factor of aseismic bearings was estimated to be 15% or more. 9 figs., 1 tab.

  9. Study on structural system of Sutong Bridge

    Institute of Scientific and Technical Information of China (English)

    Zhang Xigang; Pei Minshan; Yuan Hong; Xu Liping; Zhu Bin

    2009-01-01

    Sutong Bridge, whose layout is [ (100 + 100 + 300) + 1 088 + ( 300 + 100 + 100) ] m, marks the largest span of cable-stayed bridges in the world. The complex natural condition at the bridge site and the strict requirements for resistance of wind and seismic action make it crucial to choose a favorable structural system to assure the function and safety of the bridge. The comparison among several optional structural systems for Sutong Bridge is illustrated. After detailed analysis is carried out for viscous damper and hydraulic buffer, super liquid viscous damper with additional displacement limitation is designed for the first application in bridge engineering. The parameters for the damper is analyzed and studied and the dampers are installed suecessfuUy after quality tests.

  10. Evaluation method research on prestressed concrete bridges

    Institute of Scientific and Technical Information of China (English)

    HUANG Qiao; LIN Yang-zi; REN Yuan

    2008-01-01

    Considering the construction features of prestressed concrete bridge, the comprehensive evaluation method about the bridge damage conditions are studied. Particular attentions are paid on establishing a multi-level evaluation model for damaged prestressed concrete bridge, and the evaluation indices of the model as well as the rating standards are defined in the model. A normal relative function about the evaluation indices of each element is developed to calculate the relative degree, and for each element which is no sub-level elements. When evaluating the elements in sub-item level or index level of the model, the weights of elements that are pertained to one element are adopted, taking account of their deterioration degree. At the same time, the dam-age conditions of bridge are characterized by relative degree, element evaluation scale and structural technology mark of bridge ,so it agrees with Code for Maintenance of Highway Bridges and Culvers.

  11. Seismic Evaluation of Highway Bridges - Phase 1

    OpenAIRE

    Ramirez, J.A.; Pan, Austin D.; Mwakasisi, Frank Thompson

    1996-01-01

    The primary objective of the study was to establish the guidelines for screening, assessing, and ranking Indiana bridges for seismic upgrade. The outcome of the study is a complete strategy for the detailed structural assessment of Indiana highway bridges subjected to seismic forces. The structural evaluation is conducted using a nonlinear time-history analysis of the bridge for simulated or actual records. The specific soil conditions at the site are accounted in terms of the ground motio...

  12. REPORT: BioMedBridges standards workshop

    OpenAIRE

    Conte, Nathalie; Hancocks, Tom; Suhr, Stephanie

    2014-01-01

    This workshop, co-organized by BioMedBridges WP3 and 12, was held on 24-25 June and hosted by BioMedBridges partners at VUMC in Amsterdam. Attendees included BioMedBridges personnel, members from the ESFRI BMS research infrastructures and invited external experts from existing standards organisations. The following aspects of data standardisation were explored: Defining entity identifiers and identifiers best practice Development of a Meta models and Mappings Registry for bio...

  13. Analysis of liquid bridge between spherical particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A pair of central moving spherical particles connected by a pendular liquid bridge with interstitial Newtonian fluid is often encountered in pariculate coalescence process. In this paper, by assuming perfect-wet condition, the effects of liquid volume and separation distance on static liquid bridge are analyzed, and the relation between rupture energy and liquid bridge volume is also studied. These points would be of significance in industrial processes related to adhesive particles.

  14. Bridge engineering handbook construction and maintenance

    CERN Document Server

    Chen, Wai-Fah

    2014-01-01

    Over 140 experts, 14 countries, and 89 chapters are represented in the second edition of the Bridge Engineering Handbook. This extensive collection highlights bridge engineering specimens from around the world, contains detailed information on bridge engineering, and thoroughly explains the concepts and practical applications surrounding the subject.Published in five books: Fundamentals, Superstructure Design, Substructure Design, Seismic Design, and Construction and Maintenance, this new edition provides numerous worked-out examples that give readers step-by-step design procedures, includes c

  15. Markovian Bridges: Weak continuity and pathwise constructions

    OpenAIRE

    Chaumont, Loïc; Uribe Bravo, Gerónimo

    2009-01-01

    A Markovian bridge is a probability measure taken from a disintegration of the law of an initial part of the path of a Markov process given its terminal value. As such, Markovian bridges admit a natural parameterization in terms of the state space of the process. In the context of Feller processes with continuous transition densities, we construct by weak convergence considerations the only versions of Markovian bridges which are weakly continuous with respect to their parameter. We use this ...

  16. Life Cycle Assessment of a Norwegian Bridge

    OpenAIRE

    Dequidt, Thomas Charles Edouard

    2012-01-01

    Life cycle assessment (LCA) methodology aims at evaluating the environmental impacts of a product or system from a holistic approach. In this methodology, all life cycle phases of the product are identified and assessed, from the raw material acquisition to the end-of-life phase. This master thesis is dealing with the LCA of a Norwegian bridge. First, a literature review is realized by going through 14 bridge LCA references. Then, a detailed description of bridge LCA methodology ...

  17. Bridge Engineering-Oriented Parametric Model

    Institute of Scientific and Technical Information of China (English)

    周凌远; 李乔

    2004-01-01

    A new model is proposed to improve the efficiency of structural modeling. In this model, the bridge structural components are expressed with component description, parametric description and geometric description in a software system. This model provides both convenience and flexibility for users in structural modeling process. The object-oriented method is applied in the model implementation. A bridge analysis preprocessor is developed on the basis of this model. It provides an effective way for bridge modeling.

  18. Dynamics and Statics of Nonaxisymmetric Liquid Bridges

    Science.gov (United States)

    Alexander, J. Iwan D.; Resnick, Andrew H.; Slobozhanin, L. A.

    1996-01-01

    Theoretical and experimental investigation of the stability of nonaxisymmetric and nonaxisymmetric bridges contained between equal and unequal radii disks as a function of Bond and Weber number with emphasis on the transition from unstable axisymmetric to stable nonaxisymmetric shapes, are conducted. Numerical analysis of the stability of nonaxisymmetric bridges between unequal disks for various orientations of the gravity vector is performed. Experimental and theoretical investigation of large (nonaxisymmetric) oscillations and breaking of liquid bridges are also conducted.

  19. Maximal liquid bridges between horizontal cylinders

    OpenAIRE

    Cooray, Himantha; Huppert, Herbert E.; Neufeld, Jerome A

    2016-01-01

    We investigate two-dimensional liquid bridges trapped between pairs of identical horizontal cylinders. The cylinders support forces due to surface tension and hydrostatic pressure which balance the weight of the liquid. The shape of the liquid bridge is determined by analytically solving the nonlinear Laplace-Young equation. Parameters that maximize the trapping capacity (defined as the cross-sectional area of the liquid bridge) are then determined. The results show that these parameters can ...

  20. Axisymmetric long liquid bridges stability and resonances

    OpenAIRE

    Meseguer Ruiz, José; Sanz Andres, Angel Pedro; Perales Perales, José Manuel

    1990-01-01

    In this paper mathematical expressions for minimum-volume stability limits and resonance frequencies of axisymmetric long liquid bridges are presented. These expressions are valid for a wide range of liquid bridge configurations, accounting for ef-fects like unequal disks and axial microgravity in the case of minimum-volume stability limits,and unequal disks, axial microgravity,non-zero viscosity and liquid bridge volume different from the cylindrical one in the case of resonance frequenc...

  1. Crystal growth under bridge foundation

    OpenAIRE

    Ramon Tarragona, Anna; Alonso Pérez de Agreda, Eduardo

    2012-01-01

    W(H)YDOC PhD Prize 2012, durant el 4th International Workshop of Young Doctors in Geomechanics W(H)YDOC 2012. A high-speed railway viaduct experienced a sustained heave at high rates after its construction. The pillars of the bridge are founded on an Eocene hard anhydritic-gypsiferous claystone by means of massive foundations. Field investigations identified an active layer below the piles’ tips where expansions occur as a result of gypsum crystal growth in discontinuities from supersatura...

  2. Nanoclusters a bridge across disciplines

    CERN Document Server

    Jena, Purusottam

    2010-01-01

    This comprehensive book on Nanoclusters comprises sixteen authoritative chapters written by leading researchers in the field. It provides insight into topics that are currently at the cutting edge of cluster science, with the main focus on metal and metal compound systems that are of particular interest in materials science, and also on aspects related to biology and medicine. While there are numerous books on clusters, the focus on clusters as a bridge across disciplines sets this book apart from others. Delivers cutting edge coverage of cluster science Covers a broad range of topics in

  3. Family Medicine: Bridge to Life.

    Science.gov (United States)

    Luz, Clare

    2016-01-01

    Reflecting on the suicide of a close friend, this essay explores what comprises, and inspires a will to live, and how those in Family Medicine can address suicide risk even in the face of debilitating or terminal illness. Research indicates that the will to live is a measurable indicator of general well-being, distinct from depression, and an important predictor of a person's motivation to "hold on to life". As such, understanding what is at the heart of a desire to live should alter clinical practice. This essay offers ideas for ways in which to create bridges for patients that could help sustain life.

  4. A bridge to advanced mathematics

    CERN Document Server

    Sentilles, Dennis

    2011-01-01

    This helpful workbook-style ""bridge"" book introduces students to the foundations of advanced mathematics, spanning the gap between a practically oriented calculus sequence and subsequent courses in algebra and analysis with a more theoretical slant. Part 1 focuses on logic and number systems, providing the most basic tools, examples, and motivation for the manner, method, and concerns of higher mathematics. Part 2 covers sets, relations, functions, infinite sets, and mathematical proofs and reasoning. Author Dennis Sentilles also discusses the history and development of mathematics as well a

  5. Myocardial bridges: morphological and functional aspects.

    OpenAIRE

    A.G. Ferreira; Trotter, S E; König, B; Décourt, L V; Fox, K; Olsen, E G

    1991-01-01

    OBJECTIVE--To assess the arrangement of myocardial bridges. DESIGN--A necropsy study of 90 consecutive hearts (56 male, 34 female). RESULTS--Myocardial bridges, either single or multiple, were seen in 50 (55.6%) of the 90 hearts. The left anterior descending artery was the most commonly affected artery. Thirty five of the 50 hearts which contained in total 41 muscle bridges were dissected further with a magnifying glass. Two different types of muscle bridges could be identified. Thirty one of...

  6. A data management infrastructure for bridge monitoring

    Science.gov (United States)

    Jeong, Seongwoon; Byun, Jaewook; Kim, Daeyoung; Sohn, Hoon; Bae, In Hwan; Law, Kincho H.

    2015-04-01

    This paper discusses a data management infrastructure framework for bridge monitoring applications. As sensor technologies mature and become economically affordable, their deployment for bridge monitoring will continue to grow. Data management becomes a critical issue not only for storing the sensor data but also for integrating with the bridge model to support other functions, such as management, maintenance and inspection. The focus of this study is on the effective data management of bridge information and sensor data, which is crucial to structural health monitoring and life cycle management of bridge structures. We review the state-of-the-art of bridge information modeling and sensor data management, and propose a data management framework for bridge monitoring based on NoSQL database technologies that have been shown useful in handling high volume, time-series data and to flexibly deal with unstructured data schema. Specifically, Apache Cassandra and Mongo DB are deployed for the prototype implementation of the framework. This paper describes the database design for an XML-based Bridge Information Modeling (BrIM) schema, and the representation of sensor data using Sensor Model Language (SensorML). The proposed prototype data management framework is validated using data collected from the Yeongjong Bridge in Incheon, Korea.

  7. Review of Energy Harvesters Utilizing Bridge Vibrations

    Directory of Open Access Journals (Sweden)

    Farid Ullah Khan

    2016-01-01

    Full Text Available For health monitoring of bridges, wireless acceleration sensor nodes (WASNs are normally used. In bridge environment, several forms of energy are available for operating WASNs that include wind, solar, acoustic, and vibration energy. However, only bridge vibration has the tendency to be utilized for embedded WASNs application in bridge structures. This paper reports on the recent advancements in the area of vibration energy harvesters (VEHs utilizing bridge oscillations. The bridge vibration is narrowband (1 to 40 Hz with low acceleration levels (0.01 to 3.8 g. For utilization of bridge vibration, electromagnetic based vibration energy harvesters (EM-VEHs and piezoelectric based vibration energy harvesters (PE-VEHs have been developed. The power generation of the reported EM-VEHs is in the range from 0.7 to 1450000 μW. However, the power production by the developed PE-VEHs ranges from 0.6 to 7700 μW. The overall size of most of the bridge VEHs is quite comparable and is in mesoscale. The resonant frequencies of EM-VEHs are on the lower side (0.13 to 27 Hz in comparison to PE-VEHs (1 to 120 Hz. The power densities reported for these bridge VEHs range from 0.01 to 9539.5 μW/cm3 and are quite enough to operate most of the commercial WASNs.

  8. Gust loading on streamlined bridge decks

    DEFF Research Database (Denmark)

    Larose, Guy; Mann, Jakob

    1998-01-01

    The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin of the an......The current analytical description of the buffeting action of wind on long-span bridges is based on the strip assumption. However, recent experiments on closed-box girder bridge decks have shown that this assumption is not valid and is the source of an important part of the error margin...

  9. 33 CFR 165.1187 - Security Zones; Golden Gate Bridge and the San Francisco-Oakland Bay Bridge, San Francisco Bay...

    Science.gov (United States)

    2010-07-01

    ... from the surface to the sea floor, within 25 yards of all piers, abutments, fenders and pilings of the...) Regulations. (1) In accordance with the general regulations in § 165.33 of this part, entry into...

  10. 49 CFR 237.101 - Scheduling of bridge inspections.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Scheduling of bridge inspections. 237.101 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRIDGE SAFETY STANDARDS Bridge Inspection § 237.101 Scheduling of bridge inspections. (a) Each bridge management program shall include a provision for scheduling...

  11. Finite element of multilayer surfacing systems on orthotropic steel bridges

    NARCIS (Netherlands)

    Li, J.; Liu, X.; Scarpas, A.; Tzimiris, G.

    2013-01-01

    Light weight orthotropic steel bridge decks have been widely utilized for bridges in seismic zones, movable bridges and long span bridges. In the last three decades, severe problems were reported in relation to asphaltic surfacing materials on orthotropic steel deck bridges. Earlier investigations h

  12. Experimental Study on Vehicle-Bridge Dynamic Characteristics of Thin-Walled Trough Girder Bridge for Urban Rail Transit%城市轨道交通薄壁槽形梁车桥动力特性试验研究

    Institute of Scientific and Technical Information of China (English)

    吴亮秦; 吴定俊; 李奇

    2011-01-01

    Field tests were conducted on a standard span thin-walled trough girder bridge for the elevated urban rail transit. The free vibration characteristics of the bridge, such as the frequency, mode and damping ratio were got. The test data for both the bridge and train during the train passing through the bridge, including the displacement, amplitude, stress and the acceleration responses of the bridge and the acceleration of the carbody were obtained and analyzed. The analysis results show that the deflection-span ratio of the girder body is less than the code limit. No resonance phenomenon occurs as the train passing through the bridge. The vertical stiffness of the girder body meets the requirements. The transverse fundamental frequency of the girder span is greater than the code value while the transverse fundamental frequency of the bridge is smaller. The lateral amplitude at the pier top is larger. The transverse stiffness of the girder body meets the requirements, whereas the stiffness of the pier is somewhat insufficient. Local vibration is found in the roadbed slab and the web. Therefore, more attention should be paid to the local stability of running lines and the web when the design speed is increased. The total longitudinal bending dynamic coefficient of the girder body is smaller than specification regulated value. However, the local transverse bending dynamic coefficient of the roadbed slab is much larger than the total longitudinal bending dynamic coefficient of the girder body. The acceleration of the bridge deck is within the limit. Judging by Sperling index and ISO2631 evaluation index, the ride comfort of the test train running on the bridge is found to be excellent. According to the test and analysis, thin-walled trough girder is proved to be suitable for elevated urban rail transit.%对城轨高架标准跨薄壁槽形梁桥进行现场测试,获得桥梁的频率、振型、阻尼比等自振特性,以及列车通过时桥梁的位移、振幅

  13. Static Load Test and Calculation on Multi-tower Cable-Stayed Bridge with Tie-down Cables%多塔下拉索斜拉桥静力荷载试验和计算分析

    Institute of Scientific and Technical Information of China (English)

    肖明葵; 王肖巍; 刘纲

    2011-01-01

    The static load test and the finite element analysis of the multi-tower cable-stayed bridge with tie-down cables are carried out. The test and analysis model of the bridge is created by referencing to the actual structure of a Changjiang River bridge. The static mechanical behaviors of such bridge with tie-down cables and the normal multi-tower cable-stayed bridge are comparatively analyzed by the static load test and the finite element analysis. It is shown that the structural system of the cable-stayed bridge with tie-down cables can effectively improve the structural rigidity and reduce the bending moment of the main beams, pylons and piers. According to the results, the best scheme about the location and number of tie-down cables is proposed.%针对加有下拉索的多塔斜拉桥这种新型的桥梁结构体系,参考某长江大桥实际工程建模,通过缩尺静力实验和有限元计算分析对比加劲索加下拉索多塔斜拉桥与常规无加劲索多塔斜拉桥的静力力学性能.试验和分析表明,加下拉索多塔斜拉桥结构体系可以有效提高结构刚度,减少塔墩根部以及主梁跨中的弯距.对比试验结果,提出了最佳的下拉索设置方案.

  14. The Bridge of Mandolin County

    Science.gov (United States)

    Lantz, Juliette M.; Feindt, Jenny E.; Lewellyn, Eric P. B.; Walczak, Mary M.

    1999-12-01

    The Bridge of Mandolin County is a case designed to teach the general chemistry principles of molar mass, ions and aqueous reactions, solubility rules, and inorganic nomenclature. Through the instructor-facilitated class discussion, students consider the options before the Mandolin Town Council regarding deicing the newly constructed bridge connecting Mandolin with a large nearby city. The students must decipher contradictory claims made on behalf of sodium chloride, the traditional deicer, and calcium magnesium acetate, a new environmentally friendly deicer, to arrive at the most cost-effective and environmentally appropriate deicing product. As they work through the analysis they raise questions that can be addressed in a laboratory setting. Four optional role-playing experiments are included, which can be used by the students to gather information helpful to resolution of the case. The case is intended to be used over two class periods, with a laboratory period in between, though suggestions for other models are provided. Laboratory procedures include an EDTA titration for Ca2+ and Mg2+, a gravimetric analysis, a qualitative examination of ions and solubility, an introduction to freezing point depression and measurement, and an experimental design activity. This case can also successfully be used without alteration in non-majors chemistry or environmental chemistry courses, or upper-level analytical or environmental chemistry courses.

  15. Bridge Blasting Protection Technology Close to Existing Line%临近既有线桥梁爆破防护技术

    Institute of Scientific and Technical Information of China (English)

    郭煜

    2015-01-01

    新白沙沱长江特大桥3号墩位于长江深水区,临近既有运营铁路桥梁,施工前需爆破清理河床基底。文中通过合理选择施工机具和爆破物品、采用水下微差爆破技术,根据震动监测数据优化爆破参数,布设减震孔等方法降低了爆破振速和地震波强度,解决了水下爆破对临近既有铁路桥梁的安全控制难题。%The 3# bridge pier of Xinbaishatuo Extra Large Bridge across Yangtze River is located at the deep water area of Yangtze River,it is adjacent to existing railway bridge in operation,and the base-ment of riverbed needs to be cleared by blasting before construction.Through reasonable selection of construction implements and blasting objects,underwater micro-difference blasting technique is adopt-ed for this engineering,and by optimizing the blasting parameters according to the shock monitoring data and arranging shock-absorbing hole,etc.,the blasting vibration speed and intensity of seismic wave are greatly decreased.The safety control problem of nearby existing railway bridge affected by underwater blasting is solved.

  16. Analysis of Elastic-plastic Seismic Response of Non-regular Highway Bridge%非规则公路桥梁弹塑性地震响应分析

    Institute of Scientific and Technical Information of China (English)

    王菲; 田山坡; 禚一

    2012-01-01

    研究目的:桥梁工程作为震区交通线的重要枢纽工程,其抗震性能关系到抗震救灾工作的大局.多次破坏性地震一再显示了桥梁工程遭到破坏的严重后果,也一再显示了对桥梁工程进行正确抗震设计的重要性.因此,有必要对桥梁结构的抗震问题进行详尽的分析和论述.研究结论:以京良路改建工程上跨京广铁路立交桥为工程背景,对该桥进行了模态分析并验算了E1地震作用下的结构强度以及E2地震作用下的结构变形.经过验算与分析,本项目结构在E1地震作用下,结构满足强度要求;在E2作用下,塑性角区域的最大转角验算均满足规范要求;墩顶最大位移为2.59 cm,发生在人工波3激励下的5号墩墩顶并小于位移容许值;各桥墩的剪力设计值也远远小于容许剪力值.本项目结构满足设计的安全性和可靠性,为实际工程中桥梁结构的抗震验算提供了一定的参考依据.%Research purposes: The bridge project is as an important project in earthquake region, and it's seismic behavior is crucial to the earthquake relief work. Several destructive earthquakes show that once the bridge engineering is damaged, the serious consequence will occurred and it also shows the importance of bridge's seismic design.Therefore, it is necessary to analyze and discuss the bridge seismic design in details. Research conclusions: For reconstruction project of the interchange bridge across the Beijijing-Guangzhou Railway in Jingliang Road, the modal analysis was made and the calculation was made for the structural strength under El earthquake effect and the structure deformation under E2 earthquake effect. It proved that the bridge could meet the requirements of strength under El earthquake effect . Under E2 earthquake effect, the maximum turning angle of the plastic-hinge region met the standard requirements. The maxium displacement of the pier top was 2. 59 cm and it happened on the top of

  17. 金温线武义江桥列车走行性与行车安全指标研究%Train running performance and traffic safety index for Wuyi river bridge of Jinwen line

    Institute of Scientific and Technical Information of China (English)

    周智辉; 张军; 秦文孝; 曾庆元

    2011-01-01

    The train running performance of Wuyi river bridge was analyzed with energy random analysis theory for train derailment. The calculated result showed that though the lateral amplitude exceeds the limit value of traffic safety given by the code, the train running safety , smoothness and comfort on Wuyi river bridge can be guaranteed under the existing operation condition, and the measures of rate-limiting or reinforcement are not needed to be taken for this bridge. By comparison between the lateral amplitude of the bridge and the limit value of traffic safety, it was shown that the existing limit value of traffic safety of the lateral amplitude is too conservative. A method for establishing index of traffic safety for railway bridge was proposed based on the analysis theory for train derailment, and the detailed contents were as follows; the lateral amplitude of the middle of the bridge beam was taken as an index of traffic safety for the system of beam and pier; the critical system of beam and pier to guarantee the train running safety, smoothness and comfort was determined; the lateral amplitude of the critical system of beam and pier was calculated and taken as a limit value of traffic 'safety. The limit value of lateral amplitude of traffic safety for Wuyi river bridge was deter mined as L/6200, and the study results were accepted by Jinwen railway corporation.%运用列车脱轨能量随机分析理论分析了金温线武义江桥列车走行性.计算结果表明尽管该桥横向振幅超过《检规》行车安全限值,但列车走行安全性、平稳性与舒适性有保障,在现行行车条件下,不需要对该桥采取加固或限速措施.对比超限桥梁横向振幅与《检规》行车安全限值可知,现有的桥梁横向振幅行车安全限值过于严格.基于列车脱轨能量随机分析理论,提出了铁路桥梁行车安全指标分析方法.具体内容为:确定桥梁跨中横向振幅作为梁墩系统行车安全判别参数,计

  18. Application of Lead Core Rubber Bearings to Seismic Mitigation and Isolation of Simply-Supported Girder Bridges%铅芯橡胶支座在简支梁桥减隔震中的应用

    Institute of Scientific and Technical Information of China (English)

    宋雷; 贺立新

    2012-01-01

    To study the effect of seismic mitigation and isolation of the lead core rubber bearings applied to the simply-supported girder bridges in high intensity seismic region, the Shuijing Bridge was cited as an example and was analyzed. The ANSYS was used to respectively set up the finite element models for the whole bridge of the bridge in both the seismic isolation state and non-seismic isolation state and in consideration of the ground base pile~soil interaction of the bridge, the response spectrum analysis was made, using the calculated response spectra of 10% and 2% of the 50-year exceeding probability and the time-history analysis was made as well, u-sing the seismic waves of the exceeding probability that are identical to the response spectra. The results of the analysis indicate that in the non-seismic isolation state, the displacement and internal forces of the piers of the bridge under the action of Earthquake El and E2 are great. The common plate rubber bearings can not cater for the need of strength and deformation of the piers while with the applying of the lead core rubber bearings, the displacement and internal forces of the piers are effectively reduced and sound effect of the seismic isolation has been achieved. In the analysis of the seismically-mitigated and isolated bridge, using the response spectrum analysis method and by way of considering the equivalent rigidity of the seismic isolation components in the analysis, the nonlinear issue can be simplified as the linear-elastic issue for handling.%为研究在高地震烈度区将铅芯橡胶支座应用于简支梁桥的减隔震效果,以水晶大桥为例进行分析.采用ANSYS分别建立隔震状态和非隔震状态的全桥有限元模型,考虑地基桩一土作用效应,取用50年超越概率10%和2%的计算反应谱进行反应谱分析,并取用与反应谱相同超越概率的地震波进行时程分析.分析结果表明:非隔震状态时,该桥在E1和E2地震作用下桥墩的

  19. A risk prediction model for the assessment and triage of women with hypertensive disorders of pregnancy in low-resourced settings : the miniPIERS (Pre-eclampsia Integrated Estimate of RiSk) multi-country prospective cohort study

    NARCIS (Netherlands)

    Payne, Beth A.; Hutcheon, Jennifer A.; Ansermino, J. Mark; Hall, David R.; Bhutta, Zulfiqar A.; Bhutta, Shereen Z.; Biryabarema, Christine; Grobman, William A.; Groen, Henk; Haniff, Farizah; Li, Jing; Magee, Laura A.; Merialdi, Mario; Nakimuli, Annettee; Qu, Ziguang; Sikandar, Rozina; Sass, Nelson; Sawchuck, Diane; Steyn, D. Wilhelm; Widmer, Mariana; Zhou, Jian; von Dadelszen, Peter

    2014-01-01

    Background: Pre-eclampsia/eclampsia are leading causes of maternal mortality and morbidity, particularly in low-and middle-income countries (LMICs). We developed the miniPIERS risk prediction model to provide a simple, evidence-based tool to identify pregnant women in LMICs at increased risk of deat

  20. Design of Concrete Self-Anchored Suspension Bridge of Wusong Bridge in Jilin City%吉林市雾凇大桥混凝土自锚式悬索桥设计

    Institute of Scientific and Technical Information of China (English)

    张伟; 唐贺强; 宁伯伟

    2011-01-01

    The main bridge of the Wusong Bridge in Jilin City is a 5-span continuous concrete self-anchored suspension bridge with span arrangement (35+68+150+68+35) m. A summarized account of the design and calculation of the main bridge is presented herewith. On the bridge, the transverse and vertical bearings and the longitudinal dampers are arranged in between the stiffening girder and towers. The girder is of a concrete 3-cell single box section, the depth of a typical segment of the girder is 2.5 m and towards the anchorage sections at the side spans, the segments of the girder gradually change into a depth of 6.5 m. A tower of the bridge is a concrete portal frame structure that is 54 m in height and the tower columns and the cross beams on the towers are all of rectangular hollow sections. Beneath a tower pier are the pile caps of separation type and each pile cap is supported by 9 nos. of Φ2.0 m bored piles. The main cables are respectively made up of Φ5.1 mm galvanized high strength steel wires and the hanger cables are of Φ7.0 mm low relaxation galvanized high strength parallel steel wires. In the design, the finite element software MIDAS Civil 2006, the nonlinear analysis software BNLAS for suspension bridge and the plane program SCDS are employed to calculate and analyze the bridge. The results of the calculation and analysis indicate that all checking calculation made for the bridge can conform to the relevant requirements in the codes.%吉林市雾凇大桥主桥为(35+68+150+68+35)m五跨连续混凝土自锚式悬索桥,综述该桥主桥设计与计算.该桥塔梁间设置横、竖向支座和纵向阻尼器;加劲梁采用单箱三室混凝土截面,标准段梁高2.5 m,在边跨锚固段渐变至6.5 m;桥塔采用门形框架混凝土结构,高54 m,塔身及横梁均采用矩形空心截面;桥塔墩下部采用分离式承台,单个承台布置9根φ2.0 m钻孔灌注桩;主缆采用φ5.1 mm镀锌高强钢丝,吊索采用φ7.0 mm低松弛镀锌高强

  1. Bridge Lock-up Device System

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    The Colebrand Lock-up Device (LUD) provides additional substructure strength to resist seismic forces as a structural shock transmission unit for highway bridges. This system can provide a temporary rigid link between bridge structural members under seismic, braking, or other fast-acting type loads, while permitting slow thermal movements.

  2. Paul Dirac:. Building Bridges of the Mind

    Science.gov (United States)

    Brown, Laurie M.

    2003-12-01

    Paul Dirac was a brilliant and original thinker. He used his physical intuition and his ideal of mathematical beauty to construct bridges between major areas of physics. This article discusses several such important works, including the bridge between quantum mechanics and relativity that led to his prediction of the existence of antimatter.

  3. History of cable-stayed bridges

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1999-01-01

    The principle of supporting a bridge deck by inclined tension members leading to towers on either side of the span has been known for centuries. However, the real development of cable-stayed bridges did not begin before the 1950s. Since then the free span has been increased from 183 m in the Strö...

  4. COUPLING VIBRATION OF VEHICLE-BRIDGE SYSTEM

    Institute of Scientific and Technical Information of China (English)

    陈炎; 黄小清; 马友发

    2004-01-01

    By applying the sinusoidal wave mode to simulate the rugged surface of bridge deck,accounting for vehicle-bridge interaction and using Euler-Bernoulli beam theory, a coupling vibration model of vehicle-bridge system was developed. The model was solved by mode analyzing method and Runge-Kutta method, and the dynamic response and the resonance curve of the bridge were obtained. It is found that there are two resonance regions, one represents the main resonance while the other the minor resonance, in the resonance curve. The influence due to the rugged surface, the vibration mode of bridge, and the interaction between vehicle and bridge on vibration of the system were discussed. Numerical results show that the influence due to these parameters is so significant that the effect of roughness of the bridge deck and the mode shape of the bridge can't be ignored and the vehicle velocity should be kept away from the critical speed of the vehicle.

  5. A STUDY OF BARRIERS IN BRIDGING COMMUNICATION

    OpenAIRE

    Niteen V. Dandekar

    2014-01-01

    The main objective of this paper is to make a thought provoking discussion on the role barriers in bridging communication. It focuses on the concept of communication, process and the role of language related barriers in bridging communication. It studies the significance of communication in modern human life.

  6. General framework for bridge life cycle design

    Institute of Scientific and Technical Information of China (English)

    Junhai MA; Airong CHEN; Jun HE

    2009-01-01

    Based on a detailed illustration for bridge life cycle design which comprises the processes of service life design, aesthetics design, performance design, environ-mental and ecological design, inspection, maintenance and repair design as well as cost analysis, this paper presented a general framework for bridge life cycle design comprising three design phases and six design processes.

  7. Active aerodynamic stabilisation of long suspension bridges

    DEFF Research Database (Denmark)

    Nissen, Henrik Ditlev; Sørensen, Paul Haase; Jannerup, Ole Erik

    2004-01-01

    The paper describes the addition of actively controlled appendages (flaps) attached along the length of the bridge deck to dampen wind-induced oscillations in long suppension bridges. A novel approach using control systems methods for the analysis of dynamic stability is presented. In order to ma...

  8. Lifetime Reliability Assessment of Concrete Slab Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    A procedure for lifetime assesment of the reliability of short concrete slab bridges is presented in the paper. Corrosion of the reinforcement is the deterioration mechanism used for estimating the reliability profiles for such bridges. The importance of using sensitivity measures is stressed...

  9. Re-Assessment of Concrete Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper two aspects of re-assessment of the reliability of concrete bridges are discussed namely modelling of the corrosion of reinforcement and updating of uncertain variables. The main reason for deterioration of concrete bridges is corrosion of the reinforcement. Therefore, modelling...

  10. 大跨度梁拱组合桥的梁轨相互作用设计参数研究%Study of Design Parameters of Beam-Track Interaction of Long Span Hybrid Bridge of Beam and Arch

    Institute of Scientific and Technical Information of China (English)

    戴公连; 刘瑶

    2015-01-01

    为了解梁轨相互作用设计参数对大跨度梁拱组合桥无缝线路的影响,以兰渝线广元段某(82.9+172+82.9) m梁拱组合桥为例,采用ANSYS 软件建立了考虑拱肋—吊杆—主梁—桥墩—桩基—轨道梁轨系统一体化有限元模型,分析了拱肋与吊杆升温、纵向阻力模型、吊杆间距、桥墩高度、制动力率、风荷载等参数对钢轨纵向力的传递规律。结果表明:拱肋升温对钢轨应力的影响较大,计算钢轨伸缩力时,按梁体升温15℃考虑较为安全;梁拱组合桥的梁轨相互作用根据《铁路无缝线路设计规范》计算较为安全;钢轨制动力随固定墩高度的增加而增大,固定墩的墩顶水平力与其墩高基本呈线性递减关系;钢轨应力随吊杆间距的增大而增加;钢轨的最大制动拉、压应力和固定墩的墩顶水平力均与制动力率呈线性关系;风荷载作用下,钢轨应力可达5.8 M Pa以上,风速较大区域需考虑风荷载对钢轨的影响。%To understand the effect of the design parameters of beam‐track interaction on the continuously welded rail on long span hybrid bridge of beam and arch ,a hybrid bridge of beam and arch with span arrangement (82 .9 + 172 + 82 .9 ) m on the Guangyuan section of Lanzhou‐Chongqing Railway was taken as an example ,a finite element model considering the integration of the arch rib -hanger-main beam -pier-pile foundation -beam‐track system was established ,u‐sing the software ANSYS and the effect of the design parameters ,such as the temperature rise in the arch rib and hanger ,longitudinal resistance model ,hanger spacing ,pier height ,braking force ratio and wind load ,on the longitudinal force transmission laws of the steel rail were analyzed . T he results of the analysis show that the effect of the temperature rise in the arch rib on the steel rail stress is great and w hen the steel rail expansion force is calculated

  11. John Pier, Configurazioni narrative

    Directory of Open Access Journals (Sweden)

    Alessandra Diazzi

    2009-06-01

    Full Text Available Il presente lavoro si muove in direzione di una narratologia intertestuale che integri una riflessione semiotica e strumenti di logica, ponendo al centro il concetto di «configurazione» quale modello di comprensione (Mink, Ricoeur. Il concetto di «sceneggiature intertestuali» permette di accostarsi all‘atto di lettura interpretandolo come procedimento di abduzione, attraverso cui il Lettore Modello (Eco trova nella propria enciclopedia intertestuale le cosiddette «sceneggiature» ossia «strutture di base» più o meno riconoscibili in ogni racconto. Tramite una lettura di Lolita si giunge a delineare l‘atto interpretativo come un procedimento abduttivo in cui ricorrono «sceneggiature intertestuali», potendo così individuare nel testo quei percorsi, spesso latenti, che una lettura critica deve essere capace non solo di seguire ma anche di tracciare.

  12. 跨多股道钢箱梁天桥的结构设计%The Structural Design of Steel Box Girder Pedestrian Bridge Crossing Multiple Railways

    Institute of Scientific and Technical Information of China (English)

    沈耀海

    2011-01-01

    结合西部某新建火车站进站人行天桥工程实例,分析了设计和施工的多种控制条件,论证了主梁采用钢箱梁结构的合理性.通过有限元分析和动力特性计算可知,结构设计的控制因素为竖向自振频率,采用中墩与主梁固结的连接方式可以有效地调整结构竖向自振频率.%Based on the project case of one pedestrian bridge in one new constructed railway station at west China, many controlled conditions are analyzed about structural design and engineering construction, and the rationalitles of steel box girder bridge adopted in the design are also demonstrated. It is learned from finite - element analysis and dynamic characteristics calculation that the control factor of structural design is vertical vibration frequency, which can be improved effectively by means of fixed connection between central pier and steel box girder.

  13. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.;

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum ...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...

  14. The I-35W bridge Project Website

    DEFF Research Database (Denmark)

    Kampf, Constance

    How can websites be used to rebuild trust?  In August 2007, the Interstate Highway 35-W bridge in Minneapolis, MN collapsed during rush hour.  Although many people were rescued and casualties were as limited as could be expected due to quick and effective intervention, the image of a major bridge...... collapsing during rush hour damaged the Minnesota Department of Transportation's reputation and resulted in the loss of public trust for the organization.  The ensuing bridge reconstruction project included a project website intended to rebuild this trust through transparency, community involvement......, and the use of multimodal features.  This paper looks at the I35-W bridge reconstruction project in Minneapolis through web-based communication by the Minnesota Department of Transportation (MnDOT) about the project. The MnDOT bridge reconstruction website will be examined using a combination of 1). Weick...

  15. Modified Geometry of Transition Slabs for Integral Bridges

    OpenAIRE

    Dreier, Damien

    2010-01-01

    Over the past decades, an increasing number of integral bridges have been built. This type of bridge offers various advantages in comparison with standard bridges equipped with expansion joints and bearings. In particular, integral bridges require less maintenance since they require less mechanical elements. Transition slabs, which are used in integral bridges, are directly connected to the bridge deck and therefore they are subjected to large displacements caused by creep, shrinkage and temp...

  16. Building bridges … and accelerators

    CERN Multimedia

    2009-01-01

    Lyn Evans, the LHC project leader, was awarded an honorary doctorate from the University of Geneva (UNIGE) to celebrate his role not just in building accelerators, but also in building bridges between nations. He was one of four notables honoured at the event on Friday 5 June, coinciding with the University’s 450th Anniversary. Lyn Evans arriving at the ceremony with Archbishop Desmond Tutu. "It was a big surprise when I found out I’d been nominated," recounts Evans, "but it was an even bigger surprise to find out with whom I’d been nominated". At the ceremony Evans was awarded the honorary doctorate along with three others: Archbishop Desmond Tutu, who was acclaimed for his fight against apartheid in South Africa, Mary Robinson, first woman president of Ireland and former United Nations’ high commissioner of human rights, and Pascal Lamy, Director-General of the World Trade Organization. The award ceremony, known as the �...

  17. Root coverage with bridge flap

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar Verma

    2013-01-01

    Full Text Available Gingival recession in anterior teeth is a common concern due to esthetic reasons or root sensitivity. Gingival recession, especially in multiple anterior teeth, is of huge concern due to esthetic reasons. Various mucogingival surgeries are available for root coverage. This case report presents a new bridge flap technique, which allows the dentist not only to cover the previously denuded root surfaces but also to increase the zone of attached gingiva at a single step. In this case, a coronally advanced flap along with vestibular deepening technique was used as root coverage procedure for the treatment of multiple recession-type defect. Here, vestibular deepening technique is used to increase the width of the attached gingiva. The predictability of this procedure results in an esthetically healthy periodontium, along with gain in keratinized tissue and good patient′s acceptance.

  18. Anti-seismic performance analysis of cable-stayed bridge with different bearing constraint system%不同支座约束方式下的斜拉桥抗震性能分析

    Institute of Scientific and Technical Information of China (English)

    周叶波; 徐秀丽; 刘伟庆; 田国伟

    2012-01-01

    为确定某一独塔双索面斜拉桥合理的抗震约束体系,运用有限元软件Sap,结合该桥的特点,建立了索塔纵向、过渡墩纵横向均自由和索塔纵横向、过渡墩横向均约束两种不同约束的体系下桥梁的有限元模型,这两种约束体系分别视为方案1和方案2,并对其分别进行自振特性以及的地震响应分析.结果表明,方案2和方案1相比,主塔支座处的剪力、塔柱的内力以及过渡墩和主塔支座处的位移都降低了很多,索塔约束可降低主塔的内力,从而提高主塔的安全度,因此推荐采用索塔纵横向、过渡墩横向均约束的方案.%In order to find out the appropriate seismic constraint system for single pylons and double cable planes cable-stayed bridge, the space finite element model of the bridge with different constraint system was established by using the software Sap program: tower is free in longitudinal direction and transition piers is free in longitudinal and lateral directions; tower is constrained in longitudinal and lateral directions and transition piers is constrained in lat eral direction. The two kinds of constraint system are regarded as Scheme 1 and Scheme 2. The analysis of the structural natural vibration characteristic and response under earthquake wave were carried out. The results of calculation indicate that, comparing with Scheme 1, the shear at the tower bearing, the force of tower, the displacement at tran sition piers and tower bearing of scheme 2 are all reduced,and the safety of tower of scheme 2 is enhanced. So Scheme 2 is adopted in the paper.

  19. 粉房湾长江大桥船撞风险分析与设防标准研究%Risk Analysis and Protection Criteria Study of Ship Collision of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    耿波; 徐龙

    2012-01-01

    为确定粉房湾长江大桥设防船撞力标准,采用美国AASHTO规范方法和三概率参数积分路径方法对该桥进行船撞风险分析,计算桥梁的碰撞概率和年倒塌频率,并与可接受的风险准则进行比较;确定船撞设计代表船型,采用LS-DYNA软件对船舶碰撞桥梁进行数值模拟分析.分析结果表明:该桥在2010年、2020年和2050年通航密度下的船撞风险分别为4.05×10-6、2.02×10-5、7.06×10-5;P3、P4主墩的船撞设计代表船型均为5 000吨级;近期P3、P4主墩的设防船撞力可分别取38.68 MN和27.57 MN,远期可分别取38.68 MN和24.19 MN,P3、P4主墩抗力均满足船撞设防标准.%To determine the protection criteria for ship collision forces of Fenfangwan Changjiang River Bridge, the ship collision risk of the bridge was analyzed, the collision probability and the annual bridge collapse probability were calculated by the AASHTO method'and the three-probability parameter integral path method, and the analysis and calculation were compared to the acceptable risk criteria. The representative types of ships used for the ship collision design were determined and the software LS-DYNA was used to carry out numerical simulation of the ships colliding against the bridge. The results of the analysis indicate that the ship collision risk of the bridge under the shipping-density in the years 2010, 2020 and 2050 are respectively 4. 05 X 10-6 , 2. 02 × 10-5 and 7. 06 × 10-5. The representative types of the ships colliding against the main piers P3 and P4 of the bridge are of the 5 000 tonnage, the ship collision force protection of the piers in the near future can be determined as 38. 68 MN and 27. 57 MN and in the far future can be 38. 68 MN and 24. 19 MN, which will all satisfy the protection criteria of the ship collision of the piers.

  20. Oscillations in a sunspot with light bridges

    CERN Document Server

    Yuan, Ding; Huang, Zhenghua; Li, Bo; Su, Jiangtao; Yan, Yihua; Tan, Baolin

    2014-01-01

    Solar Optical Telescope onboard Hinode observed a sunspot (AR 11836) with two light bridges (LBs) on 31 Aug 2013. We analysed a 2-hour \\ion{Ca}{2} H emission intensity data set and detected strong 5-min oscillation power on both LBs and in the inner penumbra. The time-distance plot reveals that 5-min oscillation phase does not vary significantly along the thin bridge, indicating that the oscillations are likely to originate from the underneath. The slit taken along the central axis of the wide light bridge exhibits a standing wave feature. However, at the centre of the wide bridge, the 5-min oscillation power is found to be stronger than at its sides. Moreover, the time-distance plot across the wide bridge exhibits a herringbone pattern that indicates a counter-stream of two running waves originated at the bridge sides. Thus, the 5-min oscillations on the wide bridge also resemble the properties of running penumbral waves. The 5-min oscillations are suppressed in the umbra, while the 3-min oscillations occupy...

  1. Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

    Directory of Open Access Journals (Sweden)

    Rong Chen

    2013-01-01

    Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

  2. Study of Mechanical Characteristics of Main Ship Channel Bridge of Hutong Changjiang River Bridge%沪通长江大桥主航道桥受力特征研究

    Institute of Scientific and Technical Information of China (English)

    胡所亭; 郭辉; 鞠晓臣

    2015-01-01

    沪通长江大桥主航道桥为主跨1 092 m的双塔三索面钢桁梁公铁两用斜拉桥,为验证该桥受力的合理性 ,分别建立该桥整体、局部精细化有限元模型 ,对其合理成桥状态、静活载效应、最不利荷载组合下主桁结构受力特征、桥面系受力特征等展开研究.结果表明:列车活载效应按无限长加载较有限长增加约10% ,主桁上弦强度和稳定控制区域为辅助跨跨中附近位置,下弦为辅助墩和桥塔位置.中 -活载集中力作用下 ,铁路桥面系应力由大到小依次为顶板、横梁、U肋、纵梁和底板.汽车活载作用下 ,公路桥面系桥面板与U肋连接焊缝处存在较明显应力集中 ,但量值不大;比较不同弧形缺口型式的活载应力水平 ,表明该桥弧形缺口形状设计较合理.%The main ship channel bridge of the Hutong Changjiang River Bridge is a rail-cum-road steel truss girder cable-stayed bridge with double pylons ,triple cable planes and with a main span of 1 092 m .To verify if the mechanical conditions of the bridge were reasonable ,the global and local refined finite element models for the bridge were respectively established and the mechan-ical characteristics of the main truss structures and floor systems of the bridge under the reasonable completed bridge state ,static live load effect and worst load combinations were studied .The re-sults of the study indicate that the loading of the train live load effect according to the infinite length increases by about 10% as compared to the loading according to the finite length . The strength and stability control areas of the upper chords of the main trusses are at the positions nearby the midspans of the auxiliary spans and the control areas of the lower chords are at the posi-tions of the auxiliary piers and pylons .Under the action of the concentrated forces of the China Railway Standard Live Load ,the stress of the railway floor system is in the top plate ,cross beams

  3. Signal and noise in bridging PCR

    Directory of Open Access Journals (Sweden)

    Thaler David S

    2002-07-01

    Full Text Available Abstract Background In a variant of the standard PCR reaction termed bridging, or jumping, PCR the primer-bound sequences are originally on separate template molecules. Bridging can occur if, and only if, the templates contain a region of sequence similarity. A 3' end of synthesis in one round of synthesis that terminates in this region of similarity can prime on the other. In principle, Bridging PCR (BPCR can detect a subpopulation of one template that terminates synthesis in the region of sequence shared by the other template. This study considers the sensitivity and noise of BPCR as a quantitative assay for backbone interruptions. Bridging synthesis is also important to some methods for computing with DNA. Results In this study, BPCR was tested over a 328 base pair segment of the E. coli lac operon and a signal to noise ratio (S/N of approximately 10 was obtained under normal PCR conditions with Taq polymerase. With special precautions in the case of Taq or by using the Stoffel fragment the S/N was improved to 100, i.e. 1 part of cut input DNA yielded the same output as 100 parts of intact input DNA. Conclusions In the E. coli lac operator region studied here, depending on details of protocol, between 3 and 30% per kilobase of final PCR product resulted from bridging. Other systems are expected to differ in the proportion of product that is bridged consequent to PCR protocol and the sequence analyzed. In many cases physical bridging during PCR will have no informational consequence because the bridged templates are of identical sequence, but in a number of special cases bridging creates, or, destroys, information.

  4. Human Errors and Bridge Management Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Nowak, A. S.

    Human errors are divided in two groups. The first group contains human errors, which effect the reliability directly. The second group contains human errors, which will not directly effect the reliability of the structure. The methodology used to estimate so-called reliability distributions...... on basis of reliability profiles for bridges without human errors are extended to include bridges with human errors. The first rehabilitation distributions for bridges without and with human errors are combined into a joint first rehabilitation distribution. The methodology presented is illustrated...

  5. Building the Clinical Bridge: An Australian Success

    Directory of Open Access Journals (Sweden)

    Marianne Wallis

    2012-01-01

    Full Text Available Nursing effectiveness science includes primary, secondary, and translational, clinically focused research activities which aim to improve patient or client outcomes. It is imperative, for the successful conduct of a program of nursing effectiveness science, that a clinical bridge is established between academic and healthcare service facilities. An Australian example of the development of a robust clinical bridge through the use of jointly funded positions at the professorial level is outlined. In addition, an analysis of the practical application of Lewin’s model of change management and the contribution of both servant and transformational leadership styles to the bridge building process is provided.

  6. Building the clinical bridge: an Australian success.

    Science.gov (United States)

    Wallis, Marianne; Chaboyer, Wendy

    2012-01-01

    Nursing effectiveness science includes primary, secondary, and translational, clinically focused research activities which aim to improve patient or client outcomes. It is imperative, for the successful conduct of a program of nursing effectiveness science, that a clinical bridge is established between academic and healthcare service facilities. An Australian example of the development of a robust clinical bridge through the use of jointly funded positions at the professorial level is outlined. In addition, an analysis of the practical application of Lewin's model of change management and the contribution of both servant and transformational leadership styles to the bridge building process is provided.

  7. Maxwell Tension Supports the Water Bridge

    OpenAIRE

    Widom, A.; Srivastava, Y. N.; Swain, J.; Sivasubramanian, S.

    2008-01-01

    A cylindrical flexible cable made up of pure fluid water can be experimentally spanned across a spatial gap with cable endpoints fixed to the top edges of two glass beakers. The cable has been called a water bridge in close analogy to iron cables employed to build ordinary span bridges. A necessary condition for the construction of a water bridge is that a large electric field exists parallel to and located within the water cable. Presently, there is no accepted detailed theory which quantita...

  8. Pilot testing of a hydraulic bridge exciter

    OpenAIRE

    Andersson Andreas; Ülker-Kaustell Mahir; Borg Richard; Dymén Olivier; Carolin Anders; Karoumi Raid

    2015-01-01

    This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally ...

  9. Application and Research about Viscous Damper on Jinshuigou Bridge%粘滞阻尼器在金水沟特大桥中的应用研究

    Institute of Scientific and Technical Information of China (English)

    周友权

    2012-01-01

    Jinshuigou Bridge is a continuous rigid frame girder bridge with high piers in Huanghanhou Railway. The results of seismic analysis on it showed that the bridge design was dominated by the earthquake force. So, fluid viscous dampers were set on the bridge to control the seismic responses. In the paper, the sensitivity analysis of damping coefficient and damping exponent of fluid viscous damper are performed by using nonlinear dynamic time-history method, and the shock absorption effects from different damper parameters are discussed in contrast with that of cases without the damper. It indicates that setting the viscous damper in Jinshuigou Bridge could reduce efficiently the displacement of key positions as well as the seismic response of the bridge, and so could ensure the safety of the structure under earthquake.%金水沟特大桥为黄韩侯铁路线上的一座高墩大跨刚构连续梁桥,对其进行抗震分析后发现,地震力控制桥梁的设计.为减小其地震反应,在金水沟特大桥上设置液体粘滞阻尼器.采用动力非线性时程分析方法,对非线性粘滞阻尼器的阻尼系数和阻尼指数进行参数敏感性分析,研究不同阻尼器参数对减震效果的影响,并与不设阻尼器情况的地震响应结果进行比较.分析表明,在金水沟特大桥上设置粘滞阻尼器后,可以有效地降低结构关键部位在地震作用下的位移,减小结构构件的地震力,确保结构在地震下的安全.

  10. Allegheny County-Owned Bridges Points

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the location of bridges owned by Allegheny County as centroids. If viewing this description on the Western Pennsylvania Regional Data Center’s...

  11. Allegheny County-Owned Bridges Centerlines

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — This dataset shows the bridges owned by Allegheny County. If viewing this description on the Western Pennsylvania Regional Data Center’s open data portal...

  12. Influence of Icing on Bridge Cable Aerodynamics

    DEFF Research Database (Denmark)

    Koss, Holger; Frej Henningsen, Jesper; Olsen, Idar

    2013-01-01

    In recent years the relevance of ice accretion for wind-induced vibration of structural bridge cables has been recognised and became a subject of research in bridge engineering. Full-scale monitoring and observation indicate that light precipitation at moderate low temperatures between zero and -5......°C may lead to large amplitude vibrations of bridge cables under wind action. For the prediction of aerodynamic instability quasi-steady models have been developed estimating the cable response magnitude based on structural properties and aerodynamic force coefficients for drag, lift and torsion...... forces of different bridge cables types. The experiments were conducted in a wind tunnel facility capable amongst others to simulate incloud icing conditions....

  13. Assessment of the Reliability of Concrete Bridges

    DEFF Research Database (Denmark)

    Middleton, C. R.; Thoft-Christensen, Palle

    in the wake of ever increasing traffic loads and volumes, and an ageing population of bridges subject to various mechanisms of deterioration. The goal is to optimise the allocation of limited resources whilst maintaining their bridges in a safe and serviceable condition. Reliability analysis is one tool being......Although there has been a considerable amount of research into different aspects of concrete bridge reliability, it has still not been widely adopted in professional practice other than in the development and calibration of codes. This situation appears to be changing as there has been...... adopted to assist in achieving this goal. Rather than review the specific research on this subject this paper examines a number of key issues related to the practical application of reliability analysis to the assessment of concrete bridges....

  14. Pilot testing of a hydraulic bridge exciter

    Directory of Open Access Journals (Sweden)

    Andersson Andreas

    2015-01-01

    Full Text Available This paper describes the development of a hydraulic bridge exciter and its first pilot testing on a full scale railway bridge in service. The exciter is based on a hydraulic load cylinder with a capacity of 50 kN and is intended for controlled dynamic loading up to at least 50 Hz. The load is applied from underneath the bridge, enabling testing while the railway line is in service. The system is shown to produce constant load amplitude even at resonance. The exciter is used to experimentally determine frequency response functions at all sensor locations, which serve as valuable input for model updating and verification. An FE-model of the case study bridge has been developed that is in good agreement with the experimental results.

  15. Practical Approach to Fragility Analysis of Bridges

    Directory of Open Access Journals (Sweden)

    Yasamin Rafie Nazari

    2012-12-01

    Full Text Available Damages during past earthquakes reveal seismic vulnerability of bridge structures and the necessity of probabilistic approach toward seismic performance evaluation of bridges and its interpretation in terms of decision variables such as repair cost, downtime and life loss. This Procedure involves hazard analysis, structural analysis, damage analysis and loss analysis. The purpose of present study is reviewing different methods developed to derive fragility curves for damage analysis of bridges and demonstrating a simple procedure for fragility analysis using Microsoft Office Excel worksheet to reach probability of occurring predefined level of damage due to different levels of seismic demand parameters. The input of this procedure is the intensity of ground motion and the output is an appropriate estimate of the expected damage. Different observed damages of the bridges are discussed and compared the practical definition of damage states. Different methods of fragility analyses are discussed and a practical step by step example is illustrated.

  16. Identifying hidden sexual bridging communities in Chicago.

    Science.gov (United States)

    Youm, Yoosik; Mackesy-Amiti, Mary Ellen; Williams, Chyvette T; Ouellet, Lawrence J

    2009-07-01

    Bridge populations can play a central role in the spread of human immunodeficiency virus (HIV) by providing transmission links between higher and lower prevalence populations. While social network methods are well suited to the study of bridge populations, analyses tend to focus on dyads (i.e., risk between drug and/or sex partners) and ignore bridges between distinct subpopulations. This study takes initial steps toward moving the analysis of sexual network linkages beyond individual and risk group levels to a community level in which Chicago's 77 community areas are examined as subpopulations for the purpose of identifying potential bridging communities. Of particular interest are "hidden" bridging communities; that is, areas with above-average levels of sexual ties with other areas but whose below-average AIDS prevalence may hide their potential importance for HIV prevention. Data for this analysis came from the first wave of recruiting at the Chicago Sexual Acquisition and Transmission of HIV Cooperative Agreement Program site. Between August 2005 through October 2006, respondent-driven sampling was used to recruit users of heroin, cocaine, or methamphetamine, men who have sex with men regardless of drug use, the sex partners of these two groups, and sex partners of the sex partners. In this cross-sectional study of the sexual transmission of HIV, participants completed a network-focused computer-assisted self-administered interview, which included questions about the geographic locations of sexual contacts with up to six recent partners. Bridging scores for each area were determined using a matrix representing Chicago's 77 community areas and were assessed using two measures: non-redundant ties and flow betweenness. Bridging measures and acquired immunodeficiency syndrome (AIDS) case prevalence rates were plotted for each community area on charts representing four conditions: below-average bridging and AIDS prevalence, below-average bridging and above

  17. Inspection Based Evaluation of a Danish Road Bridge

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper it is shown how an inspection-based evaluation of a Danish road bridge may be performed using the BRIDGE1 and BRIDGE2 bridge management systems produced within the EC-supported research programme "Assessment of Performance and Optimal Strategies for Inspection and Maintenance...

  18. TMACS test procedure TP012: Panalarm software bridge

    International Nuclear Information System (INIS)

    This Test Procedure addresses the testing of the functionality of the Tank Monitor and Control System (TMACS) Panalarm bridge software. The features to be tested are: Bridge Initialization Options; Bridge Communication; Bridge Performance; Testing Checksum Errors; and Testing Command Reject Errors. Only the first three could be tested; the last two have been deferred to a later date

  19. Assessment of a Bridge WIM System on Integral Concrete Bridges and on Steel Orthotropic Decks

    OpenAIRE

    Ieng, Sio Song; SCHMIDT, Franziska; ROMBONI, Frédéric; Jacob, Bernard

    2011-01-01

    Bridge-Weigh-In-Motion uses bridges as a scale to weigh vehicles. Practically, this is done by measuring the strains in that bridge, and relating them to the weight and dimensions of a truck called “calibration trucks” whose shape and axle weights are well known. This article summarizes different B-WIM experiments the institute IFSTTAR (formerly called LCPC) realized and the lessons drawn from this experience. First, the system has been tested on frame-type bridges with integral s...

  20. Experimental study of single span railway bridges

    OpenAIRE

    Rigueiro, Constança; Rebelo, C.; Silva, L. Simões da

    2007-01-01

    The main purpose of this paper is to present some results concerning the investigation that has been done by the authors regarding the dynamic response of small to médium span railway bridges using response acceleration data colleted during the measurements carried out on single span bridges on the railway track Linz-Wels, in Austria. Using output-only methods in this experimental program, it was possible to have an estimation of the igenfrequencies, mode shapes and the corresponding viscous ...

  1. Active control of vibrations in pedestrian bridges

    OpenAIRE

    Álvaro Cunha; Carlos Moutinho

    1999-01-01

    This paper, apart from making a brief general reference to vibration problems in pedestrian bridges, as well as to the form of modelling of dynamic pedestrian loads, presents the use of a predictive control strategy for the numerical simulation of the dynamic response of actively controlled structures of this type. The consideration of this control strategy permitted the development of a computational model, which was applied to the study of a pedestrian cable-stayed bridge, in order to show ...

  2. Building Organic Bridges: Volume 1, Argentina - France

    OpenAIRE

    Rahmann, Gerold; Aksoy, Uygun

    2014-01-01

    [Foreword ...] The 18th IFOAM Organic World Congress held on 13-15 October, 2014 in Istanbul-Turkey targets to 'build organic bridges'. The Scientific track will contribute to bridging not only scientists but also institutions and disciplines, and to linking more developed and less developed, rural and urban, research to extension, plant to animal, farm practices to world-wide problems and producer and consumers. Organic is a management system that requires a diversity of inputs from differen...

  3. Building Organic Bridges: Volume 2, Germany - India

    OpenAIRE

    Rahmann, Gerold; Aksoy, Uygun

    2014-01-01

    [Foreword ...] The 18th IFOAM Organic World Congress held on 13-15 October, 2014 in Istanbul-Turkey targets to 'build organic bridges'. The Scientific track will contribute to bridging not only scientists but also institutions and disciplines, and to linking more developed and less developed, rural and urban, research to extension, plant to animal, farm practices to world-wide problems and producer and consumers. Organic is a management system that requires a diversity of inputs from differen...

  4. Thermal Bridge Effects in Walls Separating Rowhouses

    DEFF Research Database (Denmark)

    Rose, Jørgen

    1997-01-01

    In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures.......In this report the thermal bridge effects at internal wall/roof junctions in rowhouses are evaluated. The analysis is performed using a numerical calculation programme, and different solutions are evaluated with respect to extra heat loss and internal surface temperatures....

  5. External Prestressing Bridge Reinforcement Technology Review

    Directory of Open Access Journals (Sweden)

    Zhu Hanbing

    2015-01-01

    Full Text Available Externally prestressed bridge can not only limit and reduce the cracks and deformation of the structure, improve the rigidity and bearing capacity of structure, improve the stress state of structure, but also have less interference for bridge operation when it is operating and have the good economic efficiency. This paper introduces the advantages and disadvantages of external prestressed strengthening technique, its calculation theory and construction technology described in detail, and finally the paper discusses the deficiency of existing research.

  6. Subscapularis Tendon Repair Using Suture Bridge Technique

    OpenAIRE

    Park, Yong Bok; Park, Young Eun; Koh, Kyoung Hwan; Lim, Tae Kang; Shon, Min Soo; Yoo, Jae Chul

    2015-01-01

    The subscapularis tendon plays an essential role in shoulder function. Although subscapularis tendon tears are less common than other rotator cuff tears, tears of the subscapularis tendon have increasingly been recognized with the advent of magnetic resonance imaging and arthroscopy. A suture bridge technique for the treatment of posterosuperior rotator cuff tears has provided the opportunity to improve the pressurized contact area and mean footprint pressure. However, suture bridge fixation ...

  7. Analysis of Settlement Influence on Beijing-Shanghai High-speed Railway Caused by Under-passing of Shijiazhuang-Jinan Passenger Dedicated Line's Bridge%石济客专桥梁下穿京沪高铁沉降影响分析

    Institute of Scientific and Technical Information of China (English)

    孙宗磊; 李悄

    2013-01-01

    to study the settlement influence on the Beijing - Shanghai High -speed Railway caused by under - passing of the Shijiazhuang - Jinan Passenger Dedicated Line's bridge. The Plaxis 3D finite element program was used to analyze the settlement influences on the bridge of the Beijing - Shanghai High - speed Railway when the solid bridge pier or frame bridge pier of the Shijiazhuang - Jinan Passenger Dedicated line under - passes for the purpose of determining the minimum impact on the structure and stabilizing the track alignment. Research conclusions: The analysis results illustrated that on consideration of the additional settlement of foundation caused by the newly building bridge ,the maximum unequal settlement of the adjacent solid pier structure of the existing Beijing -Shanghai High - speed Railway was 3. 2mm and the frame pier structure was 4, 3mm, and they were in the regulatory range of 5mm and feasible. It was recommended to use the solid pier structure because its additional impact was lesser than the others. In addition, it was proposed that the settlement influence on the existing high - speed railway bridge could be further reduced by extending the length of pile foundation of the new bridge properly and it also pointed out there was a variation between theoretical calculation and real data, so the perfect monitoring scheme, method, control value and early warning value would be established and improved to ensure the safe construction and safe operation of high - speed railway.

  8. Framework for Bridges Maintenance in Egypt

    Directory of Open Access Journals (Sweden)

    Hesham Abd Elkhalek

    2016-01-01

    Full Text Available The traditional approaches for bridges maintenance is proven to be inefficient as they lead to random way of spending maintenance budget and deteriorating bridge conditions. In many cases, maintenance activities are performed due to user complaints. The objective of this paper is to develop a practical and reliable framework to manage the maintenance and repair activities of Bridges network in Egypt considering performance and budget limits. The model solves an optimization problem that maximizes the average condition of the network given the limited budget using Genetic Algorithm (GA. The main tasks of the system are bridge inventory, condition assessment, deterioration using markov model, and maintenance optimization. The developed model takes into account multiple parameters including serviceability requirements, budget allocation, element importance on structural safety and serviceability, bridge impact on network, and traffic. A questionnaire is conducted to complete the research scope. The proposed model is implemented in software, which provides a friendly user interface. The results of the framework are multi – year maintenance plan for the entire network for up to five years. A case study is presented for validating and testing the model with Data collected from “General Authority for Roads, Bridges and Land Transport” in Egypt.

  9. Precast Pearl-Chain concrete arch bridges

    DEFF Research Database (Denmark)

    Halding, Philip Skov; Hertz, Kristian Dahl; Schmidt, Jacob Wittrup

    2015-01-01

    A Pearl-Chain Bridge is a closed-spandrel arch bridge consisting of a number of straight pre-fabricated so called Super-Light Deck elements put together in an arch shape by post-tensioning cables. Several Pearl-Chain arches can be positioned adjacent to each other by a crane to achieve a bridge...... the technology was used. We also study other important components and details in the Pearl-Chain Bridge concept and review the effects of different types of loads. A theoretical case study of a circular 30 m span Pearl-Chain Bridge is presented showing the influence of a number of parameters: The number of post......-tensioning cables, the rise to span ratio, the height of the filling, and the height of the Super-Light Decks. We find that Pearl-Chain Bridges can be adjusted to resist specific moment loads by changing the normal force in the arch cross section by altering the above parameters. It is also found that the negative...

  10. The application of GPR in survey of Yongshan coalmine bridge

    International Nuclear Information System (INIS)

    Ground penetrating radar (GPR) is an effective shoallow exploration method which uses the reflection of high frequency electromagnetism pulse wave to detect the object and geologic phenomena underground. With the development of electron and computer technique, the application domain of this method is keeping enlarge. Based on the working principle of GPR, this paper discussed the good effect of GPR to pier prospecting in Yongshan coal mines. Some matters that should be attentive are posed while using GPR. (authors)

  11. 嘉绍大桥项目安全管理探讨%Discussion of Security Management in the Jiashao Bridge Project

    Institute of Scientific and Technical Information of China (English)

    刘崇喜; 刘飞

    2012-01-01

    The V Project of Jiashao Bridge is characterized by the abominable natural conditions, complex hydrology conditions, numerous construction machineries , especially many heavy and temporary facilities, bridge pier construction with high altitude works and near water works as well as main trestle bridge is long and high frequency of utilization and so forth. Considering the establishment of secure regulation management system, the implementation of security responsibility, the safety production input and the security risks mortgage systems, the safety explanations and related educational training, on - site safety management, safety inspection and the hidden danger rectification, the paper discussed the prevention of major source of danger. the safety management forms and the safety project culture.%嘉绍大桥V标工程具有施工自然条件恶劣,水文状况复杂,施工机械、大型临时设施数量多,桥墩施工为高空、临水作业,主栈桥长且使用频率高等特点,从安全规章管理制度的建立、安全责任制的落实、安全生产投入和安全风险抵押金制度、安全交底和教育培训、安全现场管理、安全检查及隐患整改方面对大桥施工过程进行管理,其中对防范重大危险源、安全管理形式、格局以及项目安全文化创建进行了重点探讨。

  12. 津秦客运专线113m简支系杆拱桥平转施工技术%Construction Techniques for Horizontal Rotation of 113-m Span Simply-Supported Tied Arch Bridge on Tianjin-Qinhuangdao Passenger Dedicated Railway

    Institute of Scientific and Technical Information of China (English)

    黄旺明

    2012-01-01

    The Fengnan Bridge on Tianjin-Qinhuangdao Passenger Dedicated Railway crosses both the down line of Tianjin-Shanhaiguan Railway and the link line of Fengxu Railway with its 113-m span simply-supported tied arch bridge. In order not to interfere with the normal operation of the two railway lines under the bridge, the superstructure of the bridge was constructed by the method of completing the whole structure on scaffolding closely off the designed bridge site and integrally horizontally rotating the structure in place to the bridge site. The scaffolding had three parts of the bored pile foundations, steel pipe piles and Bailey truss and was located outside and in parallel to the down line of the Tianjin-Shanhaiguan Railway. The horizontal rotation system for erection of the bridge was composed of the large tonnage spherical hinge bearing, temporary piers and curved slipway beams over the railway lines. After the tied arch bridge became a stable structure system, the bridge was pushed about 33. 53 m along the slipway beams, horizontally rotated about 17?around the center of the spherical hinge bearing and the bridge would cross the existing railway lines to the designed bridge site. At the both ends of the girder of the bridge, the girder was then jacked up or down alternatively to finally seat the bridge on the bearings atop the permanent piers.%津秦客运专线丰南特大桥以113 m简支系杆拱桥同时跨越津山铁路下行线和丰胥联络线,为不影响津山铁路和丰胥联络线的正常运行,该桥上部结构采用异位支架成桥,整体平转至设计桥位的方法施工.异位支架由钻孔桩基础、钢管桩及贝雷梁组成,位于津山线的下行线外侧并与之平行.平转系统由大吨位球形铰支座、临时墩和圆弧形跨线滑道梁组成.拱桥形成稳定的结构体系后,沿圆弧形滑道梁顶推约33.53m,以球形铰支座为中心平转约17°后跨越既有线上空到达设计桥位,在梁体两端交替进

  13. 客运专线桥上纵连式无砟道岔伸缩力与位移影响因素分析%Influencing Factors of Temperature Force and Displacement of Longitudinally Coupled Ballastless Welded Turnout on Bridges of Dedicated Passenger Lines

    Institute of Scientific and Technical Information of China (English)

    任娟娟; 王平; 刘学毅

    2011-01-01

    Taking the longitudinally coupled ballastless turnout on the Leida Bridge of the Dedicated Wuhan-Guangzhou Passenger Line for instance, the integral finite element model of turnout (crossover)-track slab-bfidge-pier was established,in which two No. 18 welded turnouts with movable frog in the form of crossover,longitudinally coupled CRTSⅡ ballastless track,bridges and piers were regarded as one system. Laws of additional temperature forces and deformation of turnouts,track slab,bfidges and piers were analyzed on the basis the model. Besides,parameters of influence on different Parts of deformation were researched, such as the expansion stiffness of track slab, friction coefficient of the slip layer and fixing of the anchor point. Calculation results show as follows: additional longitudinal forces and displacement of stock rails due to temperature changes increase with the reduction of longitudinal slab expansion stiffness, whereas the forces of transmission components of turnonts such as position-limited devices and spacer blocks, decrease remarkably with the reduction of longitudinal slab expansion stiffness. The friction coefficient of the slip layer has no great influence on longitudinal distortions of the track structure, but it is unfavorable for stressed characteristics of piers and fixings. It is necessary to arrange anchor points on large-span bridges because their cancellation may affect stock rail displacements and pier stressing adversely.%以武广客运专线雷大特大桥铺设CRTSⅡ型纵连式无砟道岔为例,将一组客专18号渡线、CRTSⅡ型板式无砟轨道、桥梁、墩台视为一个系统,建立了岔-板-梁-墩一体化计算模型,分析了道岔、道床板、桥墩的受力和变形规律,以及道床板伸缩刚度、滑动层摩擦系数、固结机构等对各部分变形的影响.分析结果表明:基本轨伸缩附加力和纵向位移随道床板纵向伸缩刚度的减少而越大,道岔传力部件受力随道床板

  14. Response Modification Factors for Concrete Bridges in Europe

    OpenAIRE

    Kappos, A. J.; Paraskeva, T. S.; Moschonas, I. F.

    2013-01-01

    The paper presents a methodology for evaluating the actual response modification factors (q or R) of bridges and applies it to seven concrete bridges typical of the stock found in southern Europe. The usual procedure for analytically estimating the q-factor is through pushover curves derived for the bridge in (at least) its longitudinal and transverse directions. The shape of such curves depends on the seismic energy dissipation mechanism of the bridge; hence, bridges are assigned to two cate...

  15. 金温线横向振幅超限桥梁的列车走行性分析%Analysis of train running performance of bridges on Jinwen line with lateral amplitude exceeding limit value

    Institute of Scientific and Technical Information of China (English)

    周智辉; 曾胜钟; 张军; 曾庆元

    2011-01-01

    The lateral amplitudes of part bridges on Jinwen line exceed the limit value of traffic safety given by code. In order to take proper measures on these bridges, the train running performance of these bridges is needed to be evaluated urgently. The calculation model for train -bridge system vibration was presented, and train running performance of four bridges was analyzed with energy random analysis theory for derailment. The analyzed result shows that the safety, comfort and smoothness of running train on Wuyijiang bridge, Linxia bridge and Haoxi bridge can be guaranteed with existing operation condition, and rate -limiting or reinforcement are not needed. The safety of running train on Hubian bridge can' t be guaranteed, and some reinforcement measures must be taken on this bridge, and the piers are suggested to be strengthened to build up bridge lateral rigidity. Before the bridge is strengthened, the speed of freight train should be controlled under 60 km/h. The research results have been adopted on Jinwen line. Reinforcing measures on three bridges are avoided, and lots of profit has been obtained. By comparison between the lateral amplitudes of four bridges and the limit value of traffic safety given by code, it can be seen that limit value of traffic safety of lateral amplitude given by existing code is too rigorous,with which the transport capacity of existing railway bridges is restricted.%金温线部分桥梁横向振幅超过规定的行车安全限值,运营部门担心存在脱轨危险,急需对这些桥梁列车走行性进行评估,以便采取适当的处理措施.建立列车-桥梁系统振动计算模型,运用列车脱轨能量随机分析理论,分析了金温线4座预应力混凝土梁桥的列车走行性.分析结果表明:在现行行车条件下,武义江桥、岭下桥与好溪桥列车走行安全性、平稳性与舒适性有保障,不必采取限速或加固措施;湖边桥列车走行安全性不能保证,建议采取适当的加

  16. Role of multiprotein bridging factor 1 in archaea: bridging the domains?

    NARCIS (Netherlands)

    Koning, de B.; Blombach, F.; Wu Hao,; Brouns, S.J.J.; Oost, van der J.

    2009-01-01

    MBF1 (multiprotein bridging factor 1) is a highly conserved protein in archaea and eukaryotes. It was originally identified as a mediator of the eukaryotic transcription regulator BmFTZ-F1 (Bombyx mori regulator of fushi tarazu). MBF1 was demonstrated to enhance transcription by forming a bridge bet

  17. Micromechanical model of cross-over fibre bridging - Prediction of mixed mode bridging laws

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Gamstedt, E.K.; Østergaard, Rasmus Christian;

    2008-01-01

    The fracture resistance of fibre composites can be greatly enhanced by crack bridging. In situ observations of mixed mode crack growth in a unidirectional carbon-fibre/epoxy composite reveal crack bridging by single fibres and by beam-like ligaments consisting of several fibres. Based on the obse...

  18. Comprehensive Real-Time Bridge Health Monitoring System of Tongtai Bridge

    Directory of Open Access Journals (Sweden)

    Lei Su-su

    2015-01-01

    Full Text Available Tongtai Bridge is the world’s largest suspension curve-girder-skew-arch bridge, which is located in Zhangjiakou, China. The understanding of mechanics characteristics is limited to such complex bridges, so it is necessary to establish reliable health monitoring system to investigate the static and dynamic responses and monitor the safety of the bridge. A comprehensive real-time bridge health monitoring system is establish, which includes four aspects: sensor system, data acquisition and transmission system, data processing and control system, structure early warning and security assessment system. The paper systematically describes the system design principles, sensor layout, and monitoring content, then expounds system integration and function of each subsystem.

  19. A probabilistic bridge safety evaluation against floods.

    Science.gov (United States)

    Liao, Kuo-Wei; Muto, Yasunori; Chen, Wei-Lun; Wu, Bang-Ho

    2016-01-01

    To further capture the influences of uncertain factors on river bridge safety evaluation, a probabilistic approach is adopted. Because this is a systematic and nonlinear problem, MPP-based reliability analyses are not suitable. A sampling approach such as a Monte Carlo simulation (MCS) or importance sampling is often adopted. To enhance the efficiency of the sampling approach, this study utilizes Bayesian least squares support vector machines to construct a response surface followed by an MCS, providing a more precise safety index. Although there are several factors impacting the flood-resistant reliability of a bridge, previous experiences and studies show that the reliability of the bridge itself plays a key role. Thus, the goal of this study is to analyze the system reliability of a selected bridge that includes five limit states. The random variables considered here include the water surface elevation, water velocity, local scour depth, soil property and wind load. Because the first three variables are deeply affected by river hydraulics, a probabilistic HEC-RAS-based simulation is performed to capture the uncertainties in those random variables. The accuracy and variation of our solutions are confirmed by a direct MCS to ensure the applicability of the proposed approach. The results of a numerical example indicate that the proposed approach can efficiently provide an accurate bridge safety evaluation and maintain satisfactory variation. PMID:27386269

  20. Natural vibration dynamics of Rainbow Bridge, Utah

    Science.gov (United States)

    Moore, J. R.; Thorne, M. S.; Wood, J. R.; Doyle, S.; Stanfield, E.; White, B.

    2015-12-01

    We measured resonant frequencies of Rainbow Bridge, Utah, one of the world's longest rock spans, during a field experiment recording ambient vibration data. Measurements were generated over 20 hours on March 23-24, 2015 using two broadband three-component seismometers placed on the bridge, and compared to concurrent data from nearby reference stations 20 and 220 m distant. We identified seven distinct modes of vibration for Rainbow Bridge between 1 and 6 Hz. Data for each resonant frequency was then analyzed to determine the frequency-dependent polarization vector in an attempt to clarify mode shapes; e.g. the fundamental mode represents out-of-plane horizontal flexure. We compared experimental data to results of 3D numerical modal analysis, using a new photogrammetric model of Rainbow Bridge generated in this study imported into COMSOL Multiphysics. Results compare well with measured data for seven of the first eight modeled modes, matching vibrational frequencies and polarization orientations generally within 10%. Only predicted mode 6 was not explicitly apparent in our experimental data. Large site-to-reference spectral ratios resolved from experimental data indicate high amplification on the bridge as compared to nearby bedrock.

  1. Bridges in the random-cluster model

    Directory of Open Access Journals (Sweden)

    Eren Metin Elçi

    2016-02-01

    Full Text Available The random-cluster model, a correlated bond percolation model, unifies a range of important models of statistical mechanics in one description, including independent bond percolation, the Potts model and uniform spanning trees. By introducing a classification of edges based on their relevance to the connectivity we study the stability of clusters in this model. We prove several exact relations for general graphs that allow us to derive unambiguously the finite-size scaling behavior of the density of bridges and non-bridges. For percolation, we are also able to characterize the point for which clusters become maximally fragile and show that it is connected to the concept of the bridge load. Combining our exact treatment with further results from conformal field theory, we uncover a surprising behavior of the (normalized variance of the number of (non-bridges, showing that it diverges in two dimensions below the value 4cos2⁡(π/3=0.2315891⋯ of the cluster coupling q. Finally, we show that a partial or complete pruning of bridges from clusters enables estimates of the backbone fractal dimension that are much less encumbered by finite-size corrections than more conventional approaches.

  2. Study on restrainer design method for continuous bridges%连续梁桥缆索限位器设计方法

    Institute of Scientific and Technical Information of China (English)

    张华; 李建中; 彭天波

    2013-01-01

    The method to define the maximum available relative displacement (MARD) of girder bridges is presented first. Based on the existing restrainer design methods for in-span hinges of frame bridges, different simplified mechanical models are proposed according to the different characteristics and positions of the expansions of continuous bridges with laminated rubber bearings. The nonlinear properties of sliding between laminated rubber bearings and main girders, restrainers and expansion gap are included in the simplified models. The restrainer design method for each simplified model is proposed. The effectiveness of the design methods is verified by designing restrainers for an example bridge. The results from nonlinear time history analysis show that restrainers determined by the methods perform well and effectively prevent unseating of the bridge. Meanwhile the seismic demands of the piers with restrainers are increased.%首先提出了梁桥有效搭接长度的确定方法.在参考国外缆索限位器设计方法的基础上,针对采用板式橡胶支座的连续梁桥,根据不同伸缩缝位置的约束特点,提出了对应的简化力学分析模型.简化模型考虑了板式橡胶支座滑动、缆索限位器和伸缩缝约束作用的非线性特性,在此基础上提出了不同伸缩缝位置处相应的缆索限位器设计方法.采用该方法对某桥进行了缆索限位器设计,并用非线性时程分析方法对限位器设计方法的有效性进行了评估.结果表明,所提设计方法能够有效地设计约束伸缩缝处墩梁相对位移的缆索限位器刚度,但设置缆索限位器后过渡墩的抗震要求有一定的增加.

  3. Safety Evaluation of Structural Behaviors for Overweight Vehicle to Cross Prestressed Concrete Hollow Plate Girder Bridge%预应力混凝土空心板桥在特重车通过时结构性能安全评定

    Institute of Scientific and Technical Information of China (English)

    王凯; 刘建磊

    2014-01-01

    Based on the project of an overweight vehicle weighed 400 t crossed prestressed con-crete hollow plate girder bridge,the overall stiffness and strength of the bridge was evaluated by static load test on site.Combine with the result of static load test,the bearing capacity of the bridge was checked by using the established girder model,bent cap model and pier model with bridge finite element calcula-tion.The shear strength of hollow plate hinge joint was checked by referring to the existing literature.The safety evaluation conclusion was put forward on the basis of bridge status and finite element calculation which ensured the overweight vehicle to cross hollow plate girder bridge safety.%以一质量达400 t的特重车通过预应力混凝土空心板梁桥项目为背景,通过现场对桥梁检测、静载试验,评估了桥梁的整体强度和刚度。结合试验结果,运用桥梁专用有限元分析软件分别建立梁体模型及盖梁墩柱模型进行结构承载能力验算,并参考现有文献对空心板铰缝抗剪强度进行相应验算。综合桥梁现状及有限元验算结果,对空心板梁桥提出安全评定结论,确保了特重车安全通过桥梁。

  4. Fast Hough transform for automatic bridge extraction

    Science.gov (United States)

    Hao, Qiwei; Chen, Xiaomei; Ni, Guoqiang; Zhang, Huaili

    2008-03-01

    In this paper, a new method to recognize bridge in the complicated background is presented. The algorithm takes full advantages of the characteristics of the bridge image. Firstly, the image is preprocessed and the object edges are extracted. Then according to the limitations of traditional Hough transform (HT), the extraction method of the image line segment characteristic of HT is improved, which eliminates spurious peaks on the basis of global and local thresholds, discriminates the position relation between two straight line segments, and merges segments with near endpoints, etc. Experiments show that this algorithm is more precise and efficient than traditional HT, moreover it can provide a complete description of the bridge in a complicated background.

  5. MINERAL BRIDGES OF NACRE AND ITS EFFECTS

    Institute of Scientific and Technical Information of China (English)

    宋凡; 白以龙

    2001-01-01

    Nacre, or mother-of-pearl, is a kind of composites of aragonite platelets sandwiched between organic materials. Its excellent mechanical properties are thought to stem from the microarchitecture that is traditionally described as a "brick and mortar" arrangement. In this paper, a new microstructure, referred to as mineral bridge in the biomineralization, is directly observed in the organic matrix layers (mortar) of nacre. This is an indication that the organic matrix layer of nacre should be treated as a three-dimensional interface and the microarchitecture of nacre ought to be considered as a "brick-bridge-mortar" structure rather than the traditional one. Experiments and analyses show that the mineral bridges not only improve the mechanical properties of the organic matrix layers but also play an important role in the pattern of the crack extension in nacre.

  6. Fasting style collapse of a multi-span arch bridge analyze the causes of the box%某多跨空腹式箱形拱桥倒塌成因分析

    Institute of Scientific and Technical Information of China (English)

    饶奇志; 易汉斌; 俞博

    2014-01-01

    In this paper, a box-shaped multi-span arch bridge collapsed fasting accident, for example, ana-lyze the causes of its collapse. First, the bridge collapse accident scene investigation, proved a bit of geologi-cal bridge pier foundation and Conditions; secondly, according to the findings of the arch structure was seized count;moreover, considering the effect of cutting down on the pile bearing capacity of the river bed;the results show that under the riverbed leads to the bridge substructure cut transition from low pile platform for high pile caps, this time the stakes withstand compressive stress is greater than its carrying capacity, the stakes can not bear the weight of the upper structure, leading to the occurrence of arch collapsed.%本文以某多跨空腹式箱形拱桥倒塌事故为例,对其倒塌成因进行了分析。首先,对桥梁倒塌事故现场进行了调查,探明了桥墩基础及桥位地质条件情况;其次,根据调查结果对拱桥结构进行了检算;此外,考虑了河床下切对桩基承载力的影响;分析结果表明,河床下切导致该桥下部结构从低桩承台转变为高桩承台,此时木桩承受的压应力大于其承载能力,木桩已经不能承担上部结构自重的作用,导致拱桥发生倒塌。

  7. A risk prediction model for the assessment and triage of women with hypertensive disorders of pregnancy in low-resourced settings: the miniPIERS (Pre-eclampsia Integrated Estimate of RiSk multi-country prospective cohort study.

    Directory of Open Access Journals (Sweden)

    Beth A Payne

    2014-01-01

    Full Text Available Pre-eclampsia/eclampsia are leading causes of maternal mortality and morbidity, particularly in low- and middle- income countries (LMICs. We developed the miniPIERS risk prediction model to provide a simple, evidence-based tool to identify pregnant women in LMICs at increased risk of death or major hypertensive-related complications.From 1 July 2008 to 31 March 2012, in five LMICs, data were collected prospectively on 2,081 women with any hypertensive disorder of pregnancy admitted to a participating centre. Candidate predictors collected within 24 hours of admission were entered into a step-wise backward elimination logistic regression model to predict a composite adverse maternal outcome within 48 hours of admission. Model internal validation was accomplished by bootstrapping and external validation was completed using data from 1,300 women in the Pre-eclampsia Integrated Estimate of RiSk (fullPIERS dataset. Predictive performance was assessed for calibration, discrimination, and stratification capacity. The final miniPIERS model included: parity (nulliparous versus multiparous; gestational age on admission; headache/visual disturbances; chest pain/dyspnoea; vaginal bleeding with abdominal pain; systolic blood pressure; and dipstick proteinuria. The miniPIERS model was well-calibrated and had an area under the receiver operating characteristic curve (AUC ROC of 0.768 (95% CI 0.735-0.801 with an average optimism of 0.037. External validation AUC ROC was 0.713 (95% CI 0.658-0.768. A predicted probability ≥25% to define a positive test classified women with 85.5% accuracy. Limitations of this study include the composite outcome and the broad inclusion criteria of any hypertensive disorder of pregnancy. This broad approach was used to optimize model generalizability.The miniPIERS model shows reasonable ability to identify women at increased risk of adverse maternal outcomes associated with the hypertensive disorders of pregnancy. It could be

  8. 高瓦斯矿井高水材料充填墩柱沿空留巷技术%Gateway Retained Along Goaf Technology with Pier Pillar Backfilled with High Water Material in High Gassy Mine

    Institute of Scientific and Technical Information of China (English)

    史国跃

    2014-01-01

    In order to improve a high timber consumption,high labor intensity,complicated construction and low support strength of the timber pack gateway retained along the goaf,a high water material was applied to backfill the pier pillar for the gateway retained along the goaf technology in Gaohe Mine and the industrial trial was conducted in No. E1302 air return gateway.The results showed that the max convergence between the roof and floor of the timber pack gateway retained along the goaf was 286 mm,the max convergence between the roof and floor of the gateway retained along the goaf with the pier pillar backfilled with the high water material was 188 mm and the max deformation value of the pier pillar was 65 mm.The construction technology of the gateway retained along the goaf with the pier pillar backfilled with the high water material was simple.The compressive strength of the pier pillar was high and could control the deformation of the surrounding rock.Meanwhile,the ventilation cross section enlarged of the mine roadway would be favorable for the ventilation gas discharging and could prevent the gas accident occurred in the mine.%为了改善木垛沿空留巷木料消耗量大、劳动强度高、施工复杂、支护强度较低的问题,高河煤矿采用了高水材料充填墩柱沿空留巷技术,并在E1302回风巷进行了工业性试验。结果表明:木垛沿空留巷顶底板最大移近量为286 mm,采用高水材料充填墩柱沿空留巷技术顶底板最大移近量为188 mm,墩柱最大变形量为65 mm,高水材料充填墩柱沿空留巷技术施工工艺简单、墩柱抗压强度大,可有效控制围岩变形,同时增大巷道通风断面有利于风排瓦斯,防止矿井发生瓦斯事故。

  9. Bridging radiation policy and science

    International Nuclear Information System (INIS)

    Scientists, regulators, and policy makers from five continents and 20 countries reached consensus on a number of conclusions and recommendations regarding low-level ionizing radiation exposures at an international conference, 'Bridging Radiation Policy and Science,' at the Airlie Center in Warrenton, Virginia, 1-5 December 1999. The goal of the conference was to develop strategies for formulating national and international policy based on current scientific information in the context of economic, political, and social concerns. Specifically, attendees explored how to establish public policies with respect to radiation protection in view of the scientific uncertainties of the effects of low-level radiation [<100 millisievert (mSv)]. Conference participants agreed that science will not likely answer in the near future fundamental questions about the shape of the dose-response curve and mechanisms of effects of radiation at low doses. The conference endorsed the quest for a prudent and coherent radiation policy based on the International Atomic Energy Agency's (IAEA) 'evolving global framework'. The Conference participants agreed upon the following recommendations: Policy discussions on the regulation of radiation sources delivering low-level radiation should include references to natural background radiation. The conference supports the evolving global framework of the International Atomic Energy Agency (IAEA) for the safe use of radiation. The conference supports further development and evaluation of the ideas associated with the proposal on controllable dose. No radiation dose is below regulatory concern but certain levels should be below regulatory action, and appropriate dose levels should be established. Fundamental questions about the shape of the dose-response curve and mechanisms of effects of radiation at low doses are unlikely to be answered in the near future. Scientific research, including molecular and cellular radiobiology studies are critical in order

  10. Rehabilitation and Strengthening of a Railway Bridge Pier under Operating Condition%某单线铁路桥墩在线路运营状况下的加固施工

    Institute of Scientific and Technical Information of China (English)

    沈阳云

    2002-01-01

    某单线铁路桥,经检测发现明显质量缺陷,分析质量缺陷产生的原因,介绍桥墩加固施工方法,即原承台外侧增设钻孔桩,桩顶新建承台与原墩身固结,施工采用单壁钢围堰稳固墩位处河床,兼作钻孔桩平台支撑结构.

  11. 桥梁单墩不同侧向力分布模式Pushover分析方法%Pushover analysis of different distribute lateral load patterns for seismic assessment of bridge piers

    Institute of Scientific and Technical Information of China (English)

    盛光祖; 李建中; 陈亮

    2010-01-01

    Pushover分析使用一定分布模式的递增水平侧向力代表地震作用下结构惯性力的分布,分布模式的不同会直接影响Pushover分析的结果,尤其是结构高阶振型影响显著时,因此侧向力分布的选取是Pushover分析中的一个关键问题.通过选取7条强震地震波,对比了典型地震波下非线性时程分析(IDA)和采用4种不同侧向力分布模式的Pushover分析的15m、30m和60m墩的地震反应.并从总体、构件和截面三个层面对各种模式Pushover分析进行评价,分析其适用性.研究表明结构进入非线性和高阶振型影响显著时,自适应侧向力模式较其他模式Pushover分析结果更接近IDA分析结果.

  12. Modified Modal Pushover Method Applied to Seismic Analysis of High-Pier Bridge%改进模态pushover法应用于高墩桥梁抗震分析

    Institute of Scientific and Technical Information of China (English)

    龙晓鸿; 潘玲; 陈恩友; 陈宏伟

    2008-01-01

    国内外尚缺乏针对高墩桥梁抗震的设计方法.介绍了模态pushover分析方法与能力谱法相结合后的改进模态pushover分析方法,并以实例进行高阶振型对高墩桥梁抗震能力的影响分析.将其计算结果与常规加载的pushover分析方法的计算结果进行比较,分析表明在高墩桥梁中不能忽略高阶振型的影响.

  13. 邕江特大桥深水大直径钻孔灌注桩施工%Construction of deep-water large diameter bored pier of super large bridge over Yongjiang river

    Institute of Scientific and Technical Information of China (English)

    覃壮

    2004-01-01

    结合邕江特大桥18号墩深水桩基础施工实践,简述深水直径钻孔灌注桩施工中所遇到的偏孔、溶洞、卡钻和导管堵管等种种问题及采取的解决办法,对深水钻孔灌注桩水下施工的工作平台安装、清孔、钻孔、水下混凝土连续灌注等工艺作了详细介绍.为以后同类工程施工积累了一定的经验.

  14. Construction technique of hollow thin-walled piers for Yongjiang river super-long bridge%永江特大桥空心薄壁墩施工技术

    Institute of Scientific and Technical Information of China (English)

    田家琳; 刘朝英; 刘国海

    2009-01-01

    永江特大桥空心薄壁墩施工,采用高墩液压自升平台式翻模施工方法.在确保施工质量达到内实外美和高空作业安全的前提下,有效缩短了施工工期和降低了施工成本.对国内高桥墩施工采用新技术、新工艺方面具有一定的推广意义.

  15. 横风对货车通过高墩桥梁行车安全性的影响分析%The Running Safety Analysis of Freight Trains Passing on the High Pier Bridge to Cross Wind Loads

    Institute of Scientific and Technical Information of China (English)

    凌知民; 高碧波; 项海帆

    2007-01-01

    在对国内外研究成果进行简要介绍和分析的基础上,本文按一系悬挂和变摩擦阻尼建立货车的动力计算模型;轮轨作用力采用Kalker的线性接触理论并按Vermeulen-Jnhnson的非线性理论对其进行修正的方法;作为车桥系统外部激励的抖振力的时域随机风荷载按Shinozuka理论进行模拟.以某高墩连续梁刚构桥为对象,对考虑横风作用时货车的行车安全性进行了对比分析.计算结果表明:在横风作用时,背风侧的脱轨系数和轮轨作用力增加,轮重减载率减小,迎风侧的脱轨系数和轮轨作用力有所减小,轮重减载率增加;与无风时相比,横风的作用将导致车辆的行车安全性较为不利,这一结论与文献[2]的试验结果基本一致.

  16. Discussion on Simulation of Ship Impacting Bridge Pier and Anti-collision Measures%船舶撞击桥墩仿真模拟及桥墩防撞措施探讨

    Institute of Scientific and Technical Information of China (English)

    王巍

    2013-01-01

    近年来桥梁受撞击垮塌事件频繁出现,引起了社会的广泛关注.笔者运用三维有限元模型,仿真描述船桥碰撞全过程,研究船桥碰撞效应,并介绍了几种常用的桥墩防撞措施.

  17. Seismic response of bridge piers with the pile foundation considering soil-structure dynamic interaction%土—结构相互作用的桩基础桥墩的地震响应

    Institute of Scientific and Technical Information of China (English)

    董正方; 陈兴冲

    2008-01-01

    分析了整体法在求解土-结构相互作用问题时, 其粘弹性人工边界如何设置以及如何在ANSYS里实现的问题,对桩基础桥墩分别采用考虑土 -结构相互作用模型和中规定的模型进行了地震响应的计算,并对计算结果进行分析和比较,可为桩基础桥墩的设计提供参考.

  18. Extracorporeal Life Support Bridge to Ventricular Assist Device: The Double Bridge Strategy.

    Science.gov (United States)

    Marasco, Silvana F; Lo, Casey; Murphy, Deirdre; Summerhayes, Robyn; Quayle, Margaret; Zimmet, Adam; Bailey, Michael

    2016-01-01

    In patients requiring left ventricular assist device (LVAD) support, it can be difficult to ascertain suitability for long-term mechanical support with LVAD and eventual transplantation. LVAD implantation in a shocked patient is associated with increased morbidity and mortality. Interest is growing in the utilization of extracorporeal life support (ECLS) as a bridge-to-bridge support for these critically unwell patients. Here, we reviewed our experience with ECLS double bridging. We hypothesized that ECLS double bridging would stabilize end-organ dysfunction and reduce ventricular assist device (VAD) implant perioperative mortality. We conducted a retrospective review of prospectively collected data for 58 consecutive patients implanted with a continuous-flow LVAD between January 2010 and December 2013 at The Alfred Hospital, Melbourne, Victoria, Australia. Twenty-three patients required ECLS support pre-LVAD while 35 patients underwent LVAD implantation without an ECLS bridge. Preoperative morbidity in the ECLS bridge group was reflected by increased postoperative intensive care duration, blood loss, blood product use, and postoperative renal failure, but without negative impact upon survival when compared with the no ECLS group. ECLS stabilization improved end-organ function pre-VAD implant with significant improvements in hepatic and renal dysfunction. This series demonstrates that the use of ECLS bridge to VAD stabilizes end-organ dysfunction and reduces VAD implant perioperative mortality from that traditionally reported in these "crash and burn" patients.

  19. The seismic response of concrete arch bridges (with focus on the Bixby Creek bridge Carmel, California)

    Energy Technology Data Exchange (ETDEWEB)

    Hoehler, M; McCallen, D; Noble, C

    1999-06-01

    The analysis, and subsequent retrofit, of concrete arch bridges during recent years has relied heavily on the use of computational simulation. For seismic analysis in particular, computer simulation, typically utilizing linear approximations of structural behavior, has become standard practice. This report presents the results of a comprehensive study of the significance of model sophistication (i.e. linear vs. nonlinear) and pertinent modeling assumptions on the dynamic response of concrete arch bridges. The study uses the Bixby Creek Bridge, located in California, as a case study. In addition to presenting general recommendations for analysis of this class of structures, this report provides an independent evaluation of the proposed seismic retrofit for the Bixby Creek Bridge. Results from the study clearly illustrate a reduction of displacement drifts and redistribution of member forces brought on by the inclusion of material nonlinearity. The analyses demonstrate that accurate modeling of expansion joints, for the Bixby Creek Bridge in particular, is critical to achieve representative modal and transient behavior. The inclusion of near-field displacement pulses in ground motion records was shown to significantly increase demand on the relatively softer, longer period Bixby Creek Bridge arch. Stiffer, shorter period arches, however, are more likely susceptible to variable support motions arising from the canyon topography typical for this class of bridges.

  20. V. Tormis: "Bridge of Song / Brian Hunt

    Index Scriptorium Estoniae

    Hunt, Brian

    1997-01-01

    Uuest heliplaadist "V. Tormis: "Bridge of Song" - Bridge of Song; Singing aboard ship; Brides Farewell; Kihnu Island Wedding Songs; 17 Estonian Wedding Songs; Three Estonian Game Songs; Four Estonian Lullabies. Estonian Radio Choir / Toomas Kapten. Finlandia 4509 96937-2; 56:52 DDD; "People of Kalevala" - God protect us from war; Vespian Winter; Eagle Flew From the North East; Plague Memory; Vainamoinen's Words of Wisdom; The Seventeenth Rune of Kalevala. National Male Choir of Estonia. Finlandia 0630 12245-2; 56:52 DDD