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Sample records for box girder bridges

  1. Review of Elastic Analysis of Box Girder Bridges | Ezeokpube ...

    African Journals Online (AJOL)

    The importance of thin-walled box girder bridges has attracted the attention of researchers since the last five decades. A lot of literature has dealt with the analytical formulations as well as experimental investigations. Field studies have increased tremendously in the last decade. So far the agreement between the analytical ...

  2. Analysis and Optimization of Box Girder Bridges in Curved Planform

    Science.gov (United States)

    Chandra Mohan Rao, B. D. V.; Ramana Rao, N. V.

    2012-02-01

    This paper deals with the free vibration analysis and optimization of box girder bridges with curved planform. The finite element analysis of a box girder bridge is carried out and then optimized using ANSYS. The objectives of this paper are (i) minimization of volume subjected to the constraint that the fundamental frequency should be greater than the initial value and (ii) maximization of fundamental frequency with a constraint that total volume of the structure should remain constant. The shape of a box girder bridge is optimized and the results are validated by comparing it with a benchmark problem. The mode shapes of the initial and optimum solutions are also presented. The structural optimization variables used in Case-1 are the design variables (length variables, thickness variables), state variables (fundamental frequency), and the objective function (minimization of volume). The structural optimization variables used in Case-2 are the design variables (length variables, thickness variables), state variables (volume), and the objective function (maximization of fundamental frequency). In Case-1, the volume of the structure has been minimized by 56.4 % and in Case-2, the fundamental frequency of the structure has been increased by 141.9 %, which shows a better performance of the proposed methodology.

  3. Comparative Research of Extra-large-span Cable-stayed Bridge with Steel Truss Girder and Steel Box Girder

    Directory of Open Access Journals (Sweden)

    Tan Manjiang

    2015-01-01

    Full Text Available To research structural performance of extra-large-span cable-stayed bridge under different section forms, with the engineering background of a 800m main-span cable-stayed bridge with steel truss girder, the cable-stayed bridge with steel box girder is designed according to the current bridge regulations when two bridges are designed in an ultimate state of the carrying capacity, so the maximum stress and minimum stress of the stress envelope diagram are substantially the same. A comprehensive comparison is given to two types of bridge on the aspect of static force, natural vibration frequency, stability, economic performance and so on. Analysis results provide future reference for the large-span cable-stayed bridge to select between the steel truss girder and the steel box girder.

  4. Creep behavior of precast segmental box girder bridge

    Science.gov (United States)

    Xihua, Dai; Liangfang, Liu; Rong, Xian

    2017-08-01

    The concrete creep effect is more obvious when the box girder is assembled by segment. It is necessary to consider the influence of the loading value of the section at different time and the different age of concrete at different stages. In this paper, ACI209R-92, CEB-FIP MC90 and B3 and other concrete creep models are compared. The results show that the B3 model has many factors to consider and the calculation accuracy is high. Secondly, this paper discusses the influence of the segmental construction technology on the creep calculation, and puts forward the characteristics of the stress analysis of the segmental box girder. Finally, on the basis of the B3 model of concrete creep, the Midas software is used to establish the calculation model of segmental box girder, and the internal force and deformation of the box girder are calculated. The results show that the internal force and deformation of the box girder is too large due to the poor integrity of the segmental assembling process, which will seriously affect the normal service performance.

  5. Dynamic Analysis of Horizontally Curved Thin-Walled Box-Girder Bridge due to Moving Vehicle

    Directory of Open Access Journals (Sweden)

    K. Nallasivam

    2007-01-01

    Full Text Available The impact on curved box-girder bridges due to vehicle moving across rough bridge deck have been analyzed using bridge-vehicle coupled dynamics. The bridge deck unevenness has been assumed to be a homogeneous random process in space specified by a PSD function. The analysis incorporates the effect of centrifugal forces due to vehicle moving on curved bridge. The curved box-girder bridge has been numerically modeled using computationally efficient thin-walled box-beam finite elements which take into account the torsional warping, distortion and distortional warping, that are important features of thin-walled box girders. Rigid vehicle with longitudinal and transverse input to the wheels giving rise to heave-pitch-roll degrees of freedom has been considered. The theoretical bridge model used in simulation study has been validated by a free vibration experiment using impact excitation. The impact factors for several response parameters such as bending moment, shear force, torsional moment, torsional bi-moment, distortional moment, distortional bi-moment and vertical deflections have been obtained for various bridge-vehicle parameters. Both constant velocity and forward acceleration of the vehicle have been considered to examine impact factor. The results highlighted that the impact factors of a curved box girder bridge corresponding to torsion, distortion and their corresponding bimoments have been observed to be generally very high, while those of the other responses are also relatively higher than that of corresponding straight box girder bridge.

  6. review of elastic analys ew of elastic analysis of box girder bridges ...

    African Journals Online (AJOL)

    eobe

    Tel: +234-803-746-2228. REVIEW OF ELASTIC ANALYS. DEPARTMENT OF CIVIL ENGINEERING. E-mail ...... concrete box girder bridge, the Lavic Road bridge in. California, monitored over a 2-year period from ..... analysis of curved steel box beams, Masters Thesis,. University of Maryland. 52. Oleinik, J. C., and Heins, ...

  7. Effect of material uncertainties on dynamic response of segmental box girder bridge

    Directory of Open Access Journals (Sweden)

    Suchart Limkatanyu

    2007-11-01

    Full Text Available The main objective of this paper was to investigate the effect of material uncertainties on dynamic response of segmental box girder bridge subjected to a moving load, in this case a rapid passing trains. Literatures concerned with the design of segmental box girder bridge, the application of finite element analysis to model the segmental box girder bridge, and the minimum requirement for structural conditions of the bridge were described and discussed in detail. A series of finite element analysis was carried out using SAP2000 Nonlinear software. The effect was investigated by varying the Modulus of Elasticity by 5%, 10% and 15%. The results were then compared with the case of assumed uniform property which had already been checked for model accuracy using the Standard prEN 1991-2. The results showed that, for the uniform case, the dynamic responses of the bridge gave the highest response at the resonance speed. When considering the non-uniform material properties (non-uniform case, the effect of material uncertainties appeared to have an effect on both displacement and acceleration responses. Nonetheless, the dynamic factor provided in the design code was sufficient for designing the segmental box girder bridge with either uniform or non-uniform material properties for the train speeds considered in this study.

  8. Reliability Assessment for PSC Box-Girder Bridges Based on SHM Strain Measurements

    Directory of Open Access Journals (Sweden)

    Chuang Chen

    2017-01-01

    Full Text Available A reliability assessment method for prestressed concrete (PSC continuous box-girder bridges based on structural health monitoring (SHM strain measurements was proposed. First, due to the fact that measured strain was compositive and the variation periods of its components were different, a series of limit state equations under normal use limit state were given. Then, a linear fitting method was used to determine the relationship between the ambient temperature and the measured strain, which was aimed at extracting the vehicle load effect and the temperature load effect from the measured strain. Finally, according to the equivalent normalization method, the load effects unsatisfying the normal distribution by probability density function fitting were transformed, and the daily failure probabilities of monitored positions were calculated for evaluating the safety state of the girder. The results show that (1 the top plate of the box girder is more sensitive than the bottom plate to the high temperature, (2 the daily and seasonal strain variations induced by uniform temperature reveal an inconsistent tendency to the seasonal variation for mid-span cross sections, and (3 the generalized extreme value distribution is recommended for temperature gradient stress and vehicle induced stress fitting for box-girder bridges.

  9. Structural Optimization of Steel Cantilever Used in Concrete Box Girder Bridge Widening

    Directory of Open Access Journals (Sweden)

    Qian Wang

    2015-01-01

    Full Text Available The structural optimization method of steel cantilever used in concrete box girder bridge widening is illustrated in this paper. The structural optimization method of steel cantilever incorporates the conceptual layout design of steel cantilever beam based on the topological theory and the determination of the optimal location of the transverse external prestressed tendons which connect the steel cantilever and the box girder. The optimal design theory and the analysis process are illustrated. The mechanical model for the prestressed steel cantilever is built and the analytical expression of the optimal position of the transverse external tendon is deduced. At last the effectiveness of this method is demonstrated by the design of steel cantilevers which are used to widen an existing bridge.

  10. Dynamic finite element model updating of prestressed concrete continuous box-girder bridge

    Science.gov (United States)

    Lin, Xiankun; Zhang, Lingmi; Guo, Qintao; Zhang, Yufeng

    2009-09-01

    The dynamic finite element model (FEM) of a prestressed concrete continuous box-girder bridge, called the Tongyang Canal Bridge, is built and updated based on the results of ambient vibration testing (AVT) using a real-coded accelerating genetic algorithm (RAGA). The objective functions are defined based on natural frequency and modal assurance criterion (MAC) metrics to evaluate the updated FEM. Two objective functions are defined to fully account for the relative errors and standard deviations of the natural frequencies and MAC between the AVT results and the updated FEM predictions. The dynamically updated FEM of the bridge can better represent its structural dynamics and serve as a baseline in long-term health monitoring, condition assessment and damage identification over the service life of the bridge.

  11. 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.

  12. Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

    Science.gov (United States)

    An, Yun-Kyu; Song, Homin; Sohn, Hoon

    2014-09-01

    This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge.

  13. Life-Cycle Monitoring of Long-Span PSC Box Girder Bridges through Distributed Sensor Network: Strategies, Methods, and Applications

    Directory of Open Access Journals (Sweden)

    Zheheng Chen

    2015-01-01

    Full Text Available Structural health monitoring (SHM has attracted much attention in recent years, which enables early warnings of structural failure, condition assessments, and rational maintenance/repair strategies. In the context of bridges, many long-span steel bridges in China have been installed with the SHM systems; however, the applications of the SHM in prestressed concrete (PSC bridges are still rather limited. On the other hand, the PSC box girder bridges are extensively used in highway and railway systems and premature damage of these bridges is often reported, resulting in considerable maintenance and/or replacement costs. First, this paper presents a state-of-art review on the SHM of long-span PSC bridges. Monitoring strategies, methods, and previous applications for these bridges are summarized and discussed. In order to well capture the behavior of the bridge during its whole life and to maximize the use of sensors, a life-cycle monitoring strategy is proposed, in which the sensor layout is determined according to requirements for construction monitoring, completion test, and in-service monitoring. A case study is made on a three-span PSC box girder bridge in China. The system configuration, sensor layout, and data communications, and so forth, are presented. The up-to-date monitored structural responses are analyzed and compared with the design values.

  14. An alternative technique to the demolition of a prestressed concrete box-girder bridge: A case study

    Directory of Open Access Journals (Sweden)

    S.S.R. Pereira

    2017-06-01

    Full Text Available This is a case study in which the partial collapse of a prestressed concrete box-girder bridge in Brazil happened only nine days after removing the supporting scaffolding. It is believed that the actual reinforcement longitudinal steel bars in the pile caps were underestimated. Although only part of the structure had collapsed, it was decided that the whole structure should be demolished. It was claimed that there was not available alternatives for ‘in situ’ structural recovery that would not compromise local traffic and safety precaution procedures. This paper presents an alternative technique for the bridge structural recovery. The application of this technique was possible because the prestressing process used unbonded pos-tensioned concrete, i.e. the sheaths were not filled with grout. The technique was based on the use of a weld torch to cut the tensioned strands in the box-girders methodically, unloading the pillars and foundations. Experimental tests were performed ‘in loco’ and proved to be effective and safe. The application of this suggested technique ‘in situ’ is believed to be an original contribution to the knowledge.

  15. Structural health monitoring of an existing PC box girder bridge with distributed HCFRP sensors in a destructive test

    Science.gov (United States)

    Yang, Caiqian; Wu, Zhishen; Zhang, Yufeng

    2008-06-01

    The application of hybrid carbon fiber reinforced polymer (HCFRP) sensors was addressed to monitor the structural health of an existing prestressed concrete (PC) box girder bridge in a destructive test. The novel HCFRP sensors were fabricated with three types of carbon tows in order to realize distributed and broad-based sensing, which is characterized by long-gauge length and low cost. The HCFRP sensors were bonded on the bottom and side surfaces of the existing bridge to monitor its structural health. The gauge lengths of the sensors bonded on the bottom and side surfaces were 1.5 m and 1.0 m, respectively. The HCFRP sensors were distributed on the bridge for two purposes. One was to detect damage and monitor the structural health of the bridge, such as the initiation and propagation of new cracks, strain distribution and yielding of steel reinforcements. The other purpose was to monitor the propagation of existing cracks. The good relationship between the change in electrical resistance and load indicates that the HCFRP sensors can provide actual infrastructures with a distributed damage detection and structural health monitoring system. Corrections were made to this article on 13 May 2008. The corrected electronic version is identical to the print version.

  16. Optimization of Post-Tensioned Box Girder Bridges with Special Reference to Use of High-Strength Concrete Using AASHTO LRFD Method

    Directory of Open Access Journals (Sweden)

    Byungik Chang

    2012-01-01

    Full Text Available With the Federal Highway Administration-mandated implementation of the LRFD specifications, many state departments of transportation (DOTs have already started implementing LRFD specifications as developed by the AASHTO. Many aspects of the LRFD specifications are being investigated by DOTs and researchers in order for seamless implementation for design and analysis purposes. This paper presents the investigation on several design aspects of post-tensioned box girder bridges designed by LRFD Specifications using conventional or High-Strength Concrete (HSC. A computer spreadsheet application was specifically developed for this investigation. It is capable of analysis, design, and cost evaluation of the superstructure for a cast-in-place post-tensioned box girder bridge. Optimal design of a post-tensioned box girder is achievable by correct selection of design variables. Cost evaluation of superstructures with different geometrical and material configurations has led to the development of optimum design charts for these types of superstructures. Variables used to develop these charts include, among others, span length, section depth, web spacing, tendon profile, and concrete strength. It was observed that HSC enables the achievement of significantly longer span lengths and/or longer web spacing that is not achievable when using normal strength concrete.

  17. Comparison of Temperature Loadings of Bridge Girders

    Directory of Open Access Journals (Sweden)

    J. Římal

    2008-01-01

    Full Text Available This paper compares the effect of temperature changes on the superstructure of bridges, above all the effect of non-uniform temperature. Loadings according to standards ESN 73 6203, ENV 1991-1-5 and DIN 1072 are compared here. The paper shows a short summary of temperature loading according to each standard and shows the comparison of bending moments arisen from these temperature loadings on superstructure made from continuous girder from a steel-concrete box girder with a composite concrete slab. With respect to a variety of design processes, the comparison is made without any coefficient of loading, combination or material. 

  18. Modeling the response of fracture critical steel box-girder bridges.

    Science.gov (United States)

    2010-02-01

    Bridges that are classified as fracture critical by AASHTO require more frequent inspections than other types of : bridges, resulting in greater costs for their maintenance. Several historical events have shown, however, that : severe damage can occu...

  19. Seismic vulnerability assessment of a continuous steel box girder ...

    Indian Academy of Sciences (India)

    Tae-Hyung Lee

    2018-02-07

    Feb 7, 2018 ... indicate that the bridge structures equipped with seismic isolation devices (e.g. LRBs) significantly mitigated the damages due to earthquakes. Keywords. Continuous steel box girder bridge; fragility curves; seismic vulnerability assessment; damage state; nonlinear dynamic analysis; lead rubber bearing. 1.

  20. Study on the Effect and Mechanism of Aerodynamic Measures for the Vortex-Induced Vibration of Separate Pairs of Box Girders in Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    Han Xin He

    2015-01-01

    Full Text Available Although not always resulting in catastrophic failures, vortex-induced vibration (VIV response can seriously impact the fatigue life and functionality of bridges, especially for separate pairs of box girders in cable-stayed bridges. This study investigates the effects of three aerodynamic measures: grating, inclined web plate, and the baffles on separated box girders in the cable-stayed bridges. The experimental result indicates that the grating of different opening ratios can control the vortex-induced vibration effectively, and the optimized grating opening ratio set in this paper is 40%. Increasing the angle of inclined web plate has a great control on mitigation of the vortex-induced vibration. However, there is an optimum angle where the amplitude of vortex-induced vibration is the smallest at low wind speed. The amplitude of vortex-induced vibration becomes larger with the increase of the web inclined angle that exceeds the optimum angle. Comparatively, the baffles installed on both sides of the inclined webs are more effective to restrain the vortex-induced resonance. The Computational Fluent Dynamics (CFD software is utilized to investigate the mechanism of the experimental results.

  1. Prestressing force monitoring method for a box girder through distributed long-gauge FBG sensors

    Science.gov (United States)

    Chen, Shi-Zhi; Wu, Gang; Xing, Tuo; Feng, De-Cheng

    2018-01-01

    Monitoring prestressing forces is essential for prestressed concrete box girder bridges. However, the current monitoring methods used for prestressing force were not applicable for a box girder neither because of the sensor’s setup being constrained or shear lag effect not being properly considered. Through combining with the previous analysis model of shear lag effect in the box girder, this paper proposed an indirect monitoring method for on-site determination of prestressing force in a concrete box girder utilizing the distributed long-gauge fiber Bragg grating sensor. The performance of this method was initially verified using numerical simulation for three different distribution forms of prestressing tendons. Then, an experiment involving two concrete box girders was conducted to study the feasibility of this method under different prestressing levels preliminarily. The results of both numerical simulation and lab experiment validated this method’s practicability in a box girder.

  2. Development of bridge girder movement criteria for accelerated bridge construction.

    Science.gov (United States)

    2014-06-01

    End diaphragms connect multiple girders to form a bridge superstructure system for effective resistance to earthquake loads. Concrete : girder bridges that include end diaphragms consistently proved to perform well during previous earthquake events. ...

  3. Aerodynamic stability study of a long-span prestressed concrete cable-stayed bridge. Aerodynamic behavior of edge box girder under uniform flow; Chodai PC shachokyo no taifu anteisei ni kansuru kenkyu. Ichiyoryuchu ni okeru edge girder keishiki no kuriki tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, T. [Obayashi Corp., Tokyo (Japan)

    1999-01-10

    In recent years, the construction of long-span bridges is on the increase. Prestressed concrete cable-stayed bridges are dynamically very efficient structures of relatively low cost that blend in well with the landscape. Maintenance is also easy. Consequently, the adoption of edge box girders for cable-stayed bridges is increasing worldwide, but problems related to the aerodynamic stability of the structure have emerged. The aerodynamic stability of edge box girders for a prestressed concrete cable-stayed bridge was investigated under uniform flow conditions by conducting several wind tunnel experiments. As a result, the section of the bridge deck was optimized to prevent torsional flutter within an angle of attack varying from -5 to +5 degrees. It is therefore possible to guarantee the aerodynamic stability of long-span prestressed concrete cable-stayed bridges. (author)

  4. A case study of interior low-frequency noise from box-shaped bridge girders induced by running trains: Its mechanism, prediction and countermeasures

    Science.gov (United States)

    Zhang, Xun; Li, Xiaozhen; Hao, Hong; Wang, Dangxiong; Li, Yadong

    2016-04-01

    A side effect of high-speed railway and urban rail transit systems is the associated vibration and noise. Since the use of concrete viaducts is predominant in railway construction due to scarce land resources, low-frequency (20-200 Hz) structure-radiated noise from concrete bridges is a principal concern. Although it is the most commonly used bridge type, the mechanism of noise emission from box-shaped bridge girders when subjected to impact forces from moving trains, which sounds like beating a drum, has not been well studied. In this study, a field measurement was first made on a simply-supported box-shaped bridge to record the acceleration of the slabs and the associated sound pressures induced by running trains. These data indicated that a significant beat-wave noise occurred in the box-shaped cavity when the train speed was around 340 km/h, which arose from the interference between two sound waves of 75.0 Hz and 78.8 Hz. The noise leakage from the bridge expansion joint was serious and resulted in obvious noise pollution near the bridge once the beat-wave noise was generated in the cavity. The dominant frequency of the interior noise at 75.0 Hz was confirmed from the spectrum of the data and the modal analysis results, and originated from the peak vibration of the top slab due to resonance and the first-order vertical acoustic mode, which led to cavity resonance, amplifying the corresponding noise. The three-dimensional acoustic modes and local vibration modes of the slab were calculated by using the finite element method. A simplified vehicle-track-bridge coupling vibration model was then developed to calculate the wheel-rail interaction force in a frequency range of 20-200 Hz. Numerical simulations using the boundary element method confirmed the cavity resonance effect and the numerical results agreed well with the data. Based on the calibrated numerical model, three noise reduction measures, i.e., adding a horizontal baffle in the interior cavity, narrowing

  5. Strengthening steel bridge girders using CFRP.

    Science.gov (United States)

    2010-06-01

    While traditional retrofitting methods for steel bridge girders could be time consuming and uneconomical, an alternative repair method is suggested using Carbon Fiber Reinforced Polymers (CFRP) laminate strips, providing engineers with a competitive ...

  6. Shear capacity of in service prestressed concrete bridge girders.

    Science.gov (United States)

    2010-05-17

    The design of prestressed concrete bridge girders has changed significantly over the past several : decades. Specifically, the design procedure to calculate the shear capacity of bridge girders that : was used forty years ago is very different than t...

  7. Reflective Cracking between Precast Prestressed Box Girders

    Science.gov (United States)

    2017-06-30

    The adjacent precast prestressed concrete box-beam bridge is the bridge of choice for short and short-to-medium span bridges. This choice is because of the ease of construction, favorable span-to-depth ratios, aesthetic appeal, and high torsional sti...

  8. Unconventional Bearing Capacity Analysis and Optimization of Multicell Box Girders

    Directory of Open Access Journals (Sweden)

    Jovan Tepic

    2014-01-01

    Full Text Available This study deals with unconventional bearing capacity analysis and the procedure of optimizing a two-cell box girder. The generalized model which enables the local stress-strain analysis of multicell girders was developed based on the principle of cross-sectional decomposition. The applied methodology is verified using the experimental data (Djelosevic et al., 2012 for traditionally formed box girders. The qualitative and quantitative evaluation of results obtained for the two-cell box girder is realized based on comparative analysis using the finite element method (FEM and the ANSYS v12 software. The deflection function obtained by analytical and numerical methods was found consistent provided that the maximum deviation does not exceed 4%. Multicell box girders are rationally designed support structures characterized by much lower susceptibility of their cross-sectional elements to buckling and higher specific capacity than traditionally formed box girders. The developed local stress model is applied for optimizing the cross section of a two-cell box carrier. The author points to the advantages of implementing the model of local stresses in the optimization process and concludes that the technological reserve of bearing capacity amounts to 20% at the same girder weight and constant load conditions.

  9. Stress Distribution in Continuous Thin-Walled Multi-Cell Box Girder ...

    African Journals Online (AJOL)

    The modern trend in the analysis is to program the more straightforward methods for ease of computer application. Therefore, the analytical tool for this study is a MATLAB program developed by the authors for the finite strip analysis of continuous thin-walled box girder bridges. Numerical study on stress distribution was ...

  10. Design aids of NU I-girders bridges.

    Science.gov (United States)

    2010-05-01

    Precast prestressed concrete I-Girder bridges have become the most dominant bridge system in the United States. In the early design : stages, preliminary design becomes a vital first step in designing an economical bridge. Within the state of Nebrask...

  11. Suspension Bridge Flutter for Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, T.; Thoft-Christensen, Palle

    Active vibration control of long span suspension bridge flutter using separated control flaps (SFSC) has shown to increase effectively the critical wind speed of bridges. In this paper, an SFSC calculation based on modal equations of the vertical and torsional motions of the bridge girder including...... the flaps is presented. The length of the flaps attached to the girder, the flap configuration and the flap rotational angles are parameters used to increase the critical wind speed of the bridge. To illustrate the theory a numerical example is shown for a suspension bridge of 1000m+2500m+1000m span based...... on the Great Belt Bridge streamlined girder....

  12. A Finite Segment Method for Skewed Box Girder Analysis

    Directory of Open Access Journals (Sweden)

    Xingwei Xue

    2018-01-01

    Full Text Available A finite segment method is presented to analyze the mechanical behavior of skewed box girders. By modeling the top and bottom plates of the segments with skew plate beam element under an inclined coordinate system and the webs with normal plate beam element, a spatial elastic displacement model for skewed box girder is constructed, which can satisfy the compatibility condition at the corners of the cross section for box girders. The formulation of the finite segment is developed based on the variational principle. The major advantage of the proposed approach, in comparison with the finite element method, is that it can simplify a three-dimensional structure into a one-dimensional structure for structural analysis, which results in significant saving in computational times. At last, the accuracy and efficiency of the proposed finite segment method are verified by a model test.

  13. Self-Consolidating Concrete for Prestressed Bridge Girders : Research Brief

    Science.gov (United States)

    2017-08-01

    Self-consolidating concrete (SCC) is commonly used as an alternative to conventional concrete (CC) in precast, prestressed concrete (PSC) bridge girders. The high strength, highly workable mixture can flow through dense reinforcement to fill formwork...

  14. Self-Consolidating Concrete for Prestressed Bridge Girders

    Science.gov (United States)

    2017-07-01

    This document reports the findings of a research project designed to better understand material and structural performance of prestressed bridge girders made with Self-Consolidating Concrete (SCC) from Wisconsin. SCC has high potential to be used for...

  15. Effect of Construction Method on Shear Lag in Prestressed Concrete Box Girders

    Directory of Open Access Journals (Sweden)

    Shi-Jun Zhou

    2012-01-01

    Full Text Available Most of the previous researches conducted on shear lag of box girders were only concerned about simple types of structures, such as simply supported and cantilever beams. The structural systems concerned in these previous researches were considered as determined and unchangeable. In this paper, a finite element method considering shear lag and creep of concrete was presented to analyze the effect of dynamic construction process on shear lag in different types of concrete box-girder bridges. The shear lag effect of the three types of a two-span continuous concrete beam classified by construction methods was analyzed in detail according to construction process. Also, a three-span prestressed concrete box-girder bridge was analyzed according to the actual construction process. The shear lag coefficients and stresses on cross sections along the beam including shear lag were obtained. The different construction methods, the changes of structural system with the construction process, the changes of loading and boundary conditions with the construction process and time, the prestressing, and creep were all imitated in the calculations. From comparisons between the results for beams using different construction methods, useful conclusions were made.

  16. Numerical Investigation on Aerodynamic Force of Streamlined Box Girder with Uniform Air Suction

    Directory of Open Access Journals (Sweden)

    Tang Ke

    2014-06-01

    Full Text Available In the present study, the flow around a streamlined box girder with uniform air suction has been investigated numerically. Two-dimensional incompressible unsteady Reynolds averaged Navier-Stokes (URANS equations are solved in conjunction with the SST k −ω turbulence model in simulations. Taking the Great Belt Bridge girder as an example, cases of different suction positions on the girder section were discussed. The effect of the suction ratio and the angle of attack (AOA of wind also were investigated. The result showed that the aerodynamic drag force was influenced by the uniform suction through either upper surface or lower surface of the box girder. The larger the suction ratio was, the more the drag-reducing could be. The suction position and AOA had a comprehensive effect on the drag force. The vortex shedding frequency was also affected by air suction. For the aerodynamic lift force and moment, air suction showed no obvious influence. If necessary, using a combined suction scheme to reduce the aerodynamic drag force or to control the flow wake would be more efficient in engineering design.

  17. Shear capacity of in service pre-stressed concrete bridge girders.

    Science.gov (United States)

    2010-05-17

    The design of prestressed concrete bridge girders has changed significantly over the past several decades. Specifically, the design procedure to calculate the shear capacity of bridge girders that was used forty years ago is very different than those...

  18. Design, construction, and field testing of an ultra high performance concrete pi-girder bridge.

    Science.gov (United States)

    2011-01-01

    The Jakway Park Bridge in Buchanan County, Iowa is the first bridge constructed with a new prestesssed girder system composed of : precast Ultra-High Performance Concrete (UHPC). These girders employ an integral deck to facilitate construction and ar...

  19. Design and test of box girder for a large wind turbine blade

    DEFF Research Database (Denmark)

    Nielsen, Per Hørlyk; Tesauro, Angelo; Bitsche, Robert

    This report is covering the structural design and full scale test of a box girder as a part of the project “Demonstration of new blade design using manufacturing process simulations” supported by the EUDP program. A box girder with a predetermined outer geometry was designed using new inventions......, which create an inner structure in the box girder. With a combination of advanced FEM analysis and the inventions it was possible to reduce the material thickness of the cap by up to 40%. The new design of the box girder was manufactured at SSP Technology A/S, where it was demonstrated...... that the manufacturing process could include the new inventions. Subsequently the box girder was transported to the blade test facility at DTU Wind Energy. A series of test was performed with the blade to investigate the behaviour during loading, and finally the girder was loaded to ultimate failure. The report includes...

  20. Rational load rating of deck-girder bridges with girder end shear cracks in reverse orientation : technical summary.

    Science.gov (United States)

    2017-04-01

    A user interface creates a grillage model of an existing bridge and places various rating trucks on the : bridge. Equivalent flexibility analysis distributes truck live loads within deck panels to surrounding : girders and diaphragms. Stiffness matri...

  1. Extension of POA based on Fiber Element to Girder Bridge

    Science.gov (United States)

    Li, Zhenxin; Qiang, Shizhong

    2010-05-01

    Because of its main advantage of simplicity, practicality, lower computational cost and relative good results Pushover analysis (POA) has become an effective analytical tool during the last decade for the seismic assessment of buildings. But such work on bridges has been very limited. Hence, the aim of this study is to adapt POA for nonlinear seismic analysis of girder bridges, and investigate its applicability in the case of an existing river-spanning approach bridge. To three different types bridge models the nonlinear POA, which adopts fiber model nonlinear beam-column element based on flexibility approach, with return period about 2500 years is carried out. It can be concluded that POA is applicable for bridges, with some shortcomings associated with the method in general, even when it is applied for buildings. Finally the applicable selection for monitoring point and lateral load pattern is suggested according to dynamic characteristic of girder bridges.

  2. Design and test of box girder for a large wind turbine blade

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Per H.; Tesauro, A.; Bitsche, R. [Technical Univ. of Denmark. DTU Wind Energy, DTU Risoe Campus, Roskilde (Denmark)] [and others

    2012-09-15

    This report is covering the structural design and full scale test of a box girder as a part of the project ''Demonstration of new blade design using manufacturing process simulations'' supported by the EUDP program. A box girder with a predetermined outer geometry was designed using new inventions, which create an inner structure in the box girder. With a combination of advanced FEM analysis and the inventions it was possible to reduce the material thickness of the cap by up to 40%. The new design of the box girder was manufactured at SSP Technology A/S, where it was demonstrated that the manufacturing process could include the new inventions. Subsequently the box girder was transported to the blade test facility at DTU Wind Energy. A series of test was performed with the blade to investigate the behaviour during loading, and finally the girder was loaded to ultimate failure. The report includes the description of the test setup, the test and an overview over the results from the test performed on the box girder. During the final test the box girder failed at 58 % of the expected ultimate load. Unfortunately, no definite conclusion could be made concerning the failure mechanism. (Author)

  3. Shear in high strength concrete bridge girders : technical report.

    Science.gov (United States)

    2013-04-01

    Prestressed Concrete (PC) I-girders are used extensively as the primary superstructure components in Texas highway bridges. : A simple semi-empirical equation was developed at the University of Houston (UH) to predict the shear strength of PC I-girde...

  4. Reflective Cracking between Precast Prestressed Box Girders : Research Brief

    Science.gov (United States)

    2017-08-01

    Ease of construction, favorable span-to-depth ratios, aesthetic appeal and high torsional stiffness make adjacent precast prestressed concrete box-beams a popular option for short-to-medium span bridges. However, persisting durability and performance...

  5. Structural Health Monitoring of Precast Concrete Box Girders Using Selected Vibration-Based Damage Detection Methods

    Directory of Open Access Journals (Sweden)

    Zhengjie Zhou

    2010-01-01

    Full Text Available Precast, prestressed concrete box girders are commonly used as superstructure components for short and medium span bridges. Their configuration and typical side-by-side placement make large portions of these elements inaccessible for visual inspection or the application of nondestructive testing techniques. This paper demonstrates that vibration-based damage detection (VBDD is an effective alternative for monitoring their structural health. A box girder removed from a dismantled bridge was used to evaluate the ability of five different VBDD algorithms to detect and localize low levels of spalling damage, with a focus on using a small number of sensors and only the fundamental mode of vibration. All methods were capable of detecting and localizing damage to a region within approximately 1.6 times the longitudinal spacing between as few as six uniformly distributed accelerometers. Strain gauges configured to measure curvature were also effective, but tended to be susceptible to large errors in near support damage cases. Finite element analyses demonstrated that increasing the number of sensor locations leads to a proportional increase in localization accuracy, while the use of additional modes provides little advantage and can sometimes lead to a deterioration in the performance of the VBDD techniques.

  6. Optimization of the box-girder of overhead crane with constrained ...

    African Journals Online (AJOL)

    haroun

    An optimal design for minimum weight crane girder can reduce the manufacturing and operating costs. The box- girder is modeled .... a) All bats use echolocation to sense distance and they also know the difference between food/ prey and barriers in some magical ...... and Automation in Design, vol. 106, pp. 203-208, 1984.

  7. Design and construction of a cable-stayed composite girder bridge with precast RC-slabs; Purekyasuto shohan gosei keta shachokoyo no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, K. [Tokyo Metropolitan Univ. (Japan). Faculty of Technology; Shimura, T.; Tachibana, Y.; Echigo, S. [Kawada Industries Inc., Tokyo (Japan)

    1995-09-20

    A report on design and execution of cable-stayed composite girder bridge with precast RC-slabs constructed first in Japan though in small scale was described. This bridge adopted steel slabs relatively low in slab height for main slab and with two boxes slab section, and was designed at an aim of being more economic and shorter in its working term in comparison with steel girder slab type, on a base of the design in a region allowable with the existing design standards. This bridge is mainly in accordance with the regulation on continuous bridge in the prescription of road bridge, and is designed for normal RC-girder selecting between girder supports to direction normal to bridge axis as usual without using specially strong concrete to the girder. And, in order to fill with the regulation on allowable tensile stress on considering effects of creep and drying shrinkage, a method adding prestress to the slabs was adopted. Furthermore, a loop-like overlap joint for cable joint for the precast girders, expansion concrete for joint portion to compose the girder with the steel slab and so forth were adopted. 12 refs., 22 figs., 5 tabs.

  8. Performance of Bridge Decks and Girders with Lightweight Aggregate Concrete

    OpenAIRE

    Ramirez, J.A. [UNESP; Olek, J.; Rolle, Eric Joseph; Manlone, Brian J.

    2000-01-01

    Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of ha...

  9. Anchorage Zone Design for Pretensioned Precast Bulb-T Bridge Girders in Virginia

    OpenAIRE

    E.D. Crispino; Cousins, Thomas E.; Roberts-Wollmann, Carin L.

    2009-01-01

    Precast/prestressed concrete girders are commonly used in bridge construction in the United States. The application and diffusion of the prestress force in a pretensioned girder cause a vertical tension force to develop near the end of the beam. Field surveys of the beam ends of pretensioned bridge girders indicate that many of the precast bulb-T (PCBT) beams used in Virginia develop cracks within the anchorage zone region. The lengths and widths of these cracks range from acceptable to poor ...

  10. Repair methods for prestressed girder bridges.

    Science.gov (United States)

    2009-04-30

    It is common practice that aging and structurally damaged prestressed concrete bridge members are taken out of service and replaced. : This, however, is not an efficient use of materials and resources since the member can often be repaired in situ. T...

  11. Condition Assessment of PCI Bridge Girder a Result of The Reduction Prestressing Force

    Directory of Open Access Journals (Sweden)

    Suangga Made

    2014-03-01

    Full Text Available PCI bridge girders is known and widely used for many construction e.g.: bridge, wharf, flyover, and other application. PC Bridge girders have two types: Pre - tensioned girders and post - tensioned girders. In pre tensioned girders, prestressing in carried out first then after that the fresh concrete poured. The prestressing process in only carried off after the concrete has sufficient strength. In this study, analysis was conducted for PCI bridge girder with span is 40 meters. Based on the data geometry bridge dimension girder, material girder, and material strands cable, it will be analyzed to calculate the natural frequencies and moment capacity using finite element program (Midas/Civil program. So it can be estimated how much the percentage reduction prestress force on the bridge until PCI bridge structure collapses. From the calculation, it found that the pattern comparison between reduction prestressing force and natural frequency are linear. These results are also similar for natural frequency versus moment capacity.PCI bridge will collapse when the reduction prestreesing force of 45 % to 50 % from the total loss of prestressing.

  12. Condition Assessment of PCI Bridge Girder a Result of The Reduction Prestressing Force

    Science.gov (United States)

    Suangga, Made; Hidayat, Irpan; Lutter, Bobby

    2014-03-01

    PCI bridge girders is known and widely used for many construction e.g.: bridge, wharf, flyover, and other application. PC Bridge girders have two types: Pre - tensioned girders and post - tensioned girders. In pre tensioned girders, prestressing in carried out first then after that the fresh concrete poured. The prestressing process in only carried off after the concrete has sufficient strength. In this study, analysis was conducted for PCI bridge girder with span is 40 meters. Based on the data geometry bridge dimension girder, material girder, and material strands cable, it will be analyzed to calculate the natural frequencies and moment capacity using finite element program (Midas/Civil program). So it can be estimated how much the percentage reduction prestress force on the bridge until PCI bridge structure collapses. From the calculation, it found that the pattern comparison between reduction prestressing force and natural frequency are linear. These results are also similar for natural frequency versus moment capacity.PCI bridge will collapse when the reduction prestreesing force of 45 % to 50 % from the total loss of prestressing.

  13. Evaluating Louisiana new deck continuity detail for precast prestressed concrete girder bridges : research project capsule.

    Science.gov (United States)

    2014-08-01

    The goal of everyone in the transportation community is to build bridges : that are economic, easy to construct, and durable. Therefore, accelerating : bridge construction through the use of precast concrete or prefabricated : steel girders is a comm...

  14. Continuity diaphragm for skewed continuous span precast prestressed concrete girder bridges.

    Science.gov (United States)

    2004-10-01

    Continuity diaphragms used on skewed bents in prestressed girder bridges cause difficulties in detailing and : construction. Details for bridges with large diaphragm skew angles (>30) have not been a problem for LA DOTD. : However, as the skew angl...

  15. Condition Assessment of Corrosion-damaged Bridge Girders Strengthened with Post-tensioned Composite Strips

    Science.gov (United States)

    Kim, Yail J.; Kang, Jae-Yoon; Park, Jong-Sup; Jung, Woo-Tai

    2017-05-01

    This paper presents the condition evaluation of bridge girders upgraded using post-tensioned near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) strips subjected to corrosion damage. Computational models are developed to predict the behavior of the girders over a 100-year service period. Dynamic analysis exhibits that damage localization takes place, in conjunction with various mode shapes. As the extent of damage rises, the effectiveness of the NSM CFRP increases and the flexural stiffness of the girders decreases.

  16. Shear Behavior of Corrugated Steel Webs in H Shape Bridge Girders

    OpenAIRE

    Qi Cao; Haibo Jiang; Haohan Wang

    2015-01-01

    In bridge engineering, girders with corrugated steel webs have shown good mechanical properties. With the promotion of composite bridge with corrugated steel webs, in particular steel-concrete composite girder bridge with corrugated steel webs, it is necessary to study the shear performance and buckling of the corrugated webs. In this research, by conducting experiment incorporated with finite element analysis, the stability of H shape beam welded with corrugated webs was tested and three fai...

  17. Anchorage zone design for pretensioned precast bulb-T bridge girders in Virginia.

    Science.gov (United States)

    2009-01-01

    Precast/prestressed concrete girders are commonly used in bridge construction in the United States. The application and diffusion of the prestress force in a pretensioned girder cause a vertical tension force to develop near the end of the beam. Fiel...

  18. Study on the Pure Torsion Performance of I-Type Steel-Concrete Composite Bridge with Double Girders

    Science.gov (United States)

    Liu, H. C.; Wan, S.; Liu, Q. J.

    2017-11-01

    At present, the study of the torsion performance of the steel-concrete composite bridge with open sections are usually simplified to study the torsion performance of single-girder steel-concrete composite bridge added the influence of transverse vehicle distribution. Due to the existence of transverse connections between the bridge girders, the overall torsion performance of double-girder composite bridge is different from that of single-girder composite bridge. Therefore, it is necessary to study the effect of different forms of the connections on the torsional properties of the double-girder composite bridge through experiments. In this paper, three double-girder steel-concrete composite model bridges are designed to study the effect of different forms of transverse connections and the effect of different shapes of steel webs on torsional properties of composite bridges.

  19. Evaluation of Girder Cores from the US 90 Bayou Ramos Bridge

    Science.gov (United States)

    2012-05-01

    This technical assistance report documents the investigation conducted by the Louisiana Transportation Research Center (LTRC) of the cored concrete from girders of the US 90 Bayou Ramos Bridge near Morgan City, LA. The unit weights of the cores were ...

  20. Continuous prestressed concrete girder bridges, volume 2 : analysis, testing, and recommendations.

    Science.gov (United States)

    2016-12-01

    The Texas Department of Transportation designs typical highway bridge structures as simple span systems using : standard precast, pretensioned girders. Spans are limited to about 150 ft due to weight and length restrictions on : transporting the prec...

  1. Continuous prestressed concrete girder bridges volume 1 : literature review and preliminary designs.

    Science.gov (United States)

    2012-06-01

    The Texas Department of Transportation (TxDOT) is currently designing typical highway bridge structures as simply supported using standard precast, pretensioned girders. TxDOT is interested in developing additional economical design alternatives for ...

  2. Full Scale Test of a SSP 34m box girder 1. Data report

    DEFF Research Database (Denmark)

    Jensen, Find Mølholt; Branner, Kim; Nielsen, Per Hørlyk

    This report presents the setup and result of a full-scale test of a reinforced glass fibre/epoxy box girder used in 34m wind turbine blade. The tests were performed at the Blaest test facility in August 2006. The test is an important part of a research project established in cooperation between R...

  3. Development of high performance precast/prestressed bridge girders

    Science.gov (United States)

    Akhnoukh, Amin K.

    Demand continues to increase for bridges with long spans and shallow depths. Due to safety concerns, four-span overpasses are being replaced with two span overpasses to avoid placement of piers near the highway shoulders. In the meantime, the bridge profile is restricted due to existing businesses nearby. Thus, nearly the same superstructure depth must be used for double the span length. This dissertation focuses on topics aiming at providing precast prestressed concrete girders with the shallowest possible depth for a given span. It forms parts of larger projects conducted by the University of Nebraska for the Nebraska Department of Roads and for the Wire Reinforcement Institute. Specifically, the following issues were researched: (1) Use of 0.7 in. diameter Grade 270 ksi strands for pretensioning of precast concrete girders at a strand spacing of 2 inches by 2 inches. This arrangement gives nearly 190 percent of the prestressing with 0.5 in. diameter strands and nearly 135 percent with 0.6 in. strands. The research focuses on the required confinement steel to allow determination of transfer and development lengths according to current procedures in the AASHTO LRFD Bridge Design Specifications for smaller strands. (2) Develop a self consolidating concrete (SCC) mix, using Nebraska aggregates that will allow for a specified design strength at service of 15 ksi and a minimum strength at one day of 10 ksi, representing the demand at the time of release of the prestress to the concrete member. Prior to this study, standard concrete strength prevailing in Nebraska has been 8 ksi at service and 6.5 ksi at release. It was the goal of the research to keep the cost of materials as low as possible but not exceeding 250 per cubic yard, compared to the proprietary mixes that cost approximately four times this amount. (3) Use of 80 ksi welded wire reinforcement (WWR) as the auxiliary reinforcement for shear, web end splitting and flange confinement. This would result in higher

  4. Design of bridge crane girder strain acquisition system based on virtual instrument

    Directory of Open Access Journals (Sweden)

    Wenxue LIU

    Full Text Available Girder is an important part of the bridge crane, which is also the main force element. In order to prevent accidents, it is necessary to collect the bridge crane girder stress data to analyse the fatigue life. This paper constructs a bridge crane girder strain acquisition system. The hardware system consists of sensors, connectors, data acquisition cards, wireless data transmission groups, POE power and host computer. The software system consists of NI MAX to interface with the computer's NI hardware and software resources,and LabVIEW programming to display and storage the girder strain data. Through this system, positions and working days strain data acquisition for the 50/10 t bridge crane girder gets the key positions strain data. The results show that the girder strain data acquisition system runs stably, channel signals of acquisition task transmit accurately, and the terminal data stores competely, meeting the detection requirements, which provides an important data support for the subsequent fatigue analysis and accurate remaining service life prediction of the crane girder.

  5. The effect of span length and girder type on bridge costs

    Directory of Open Access Journals (Sweden)

    Batikha Mustafa

    2017-01-01

    Full Text Available Bridges have an important role in impacting the civilization, growth and economy of cities from ancient time until these days due to their function in reducing transportation cost and time. Therefore, development of bridges has been a knowledge domain in civil engineering studies in terms of their types and construction materials to confirm a reliable, safe, economic design and construction. Girder-bridge of concrete deck and I-beam girder has been used widely for short and medium span bridges because of ease and low-cost of fabrication. However, many theoretical and practical investigations are still undertaken regarding the type of beam girder; i.e steel composite or prestressed concrete. This paper evaluates the effect of bridge span and the type of girder on the capital cost and life cycle costs of bridges. Three types of girders were investigated in this research: steel composite, pre-tensioned pre-stressed concrete and post-tensioned pre-stressed concrete. The structural design was analyzed for 5 span lengths: 20, 25, 30, 35 and 40m. Then, the capital construction cost was accounted for 15 bridges according to each span and construction materials. Moreover, the maintenance required for 50 years of bridge life was evaluated and built up as whole life costs for each bridge. As a result of this study, the influence of both span length and type of girder on initial construction cost and maintenance whole life costs were assessed to support the decision makers and designers in the selection process for the optimum solution of girder bridges.

  6. Field testing of the Wolf Creek curved girder bridge : part I : vibration tests.

    Science.gov (United States)

    2009-01-01

    The Wolf Creek Bridge is a curved, multi-girder three span steel composite bridge located south of Narrows, Virginia, that was completed in 2006. A finite element model of the bridge revealed that pier flexibility may be important in modeling the bri...

  7. Investigation and Control of VIVs with Multi-Lock-in Regions on Wide Flat Box Girders

    Directory of Open Access Journals (Sweden)

    Bo Wu

    2017-01-01

    Full Text Available On the preliminary designing of a wide flat box girder with the slenderness ratio 12, vertical and torsional vortex-induced vibrations (VIV are observed in wind tunnel tests. More than one lock-in region, which are defined as “multi-lock-in regions,” are recorded. Therefore, suspicions should be aroused regarding the viewpoint that wide box girders are aerodynamic friendly. As the three nascent vortexes originating at the pedestrian guardrails and inspection rails shed to near-wake through different pathways with different frequencies, the mechanisms of VIVs and multi-lock-in regions are analyzed to be determined by the inappropriate subsidiary structures. A hybrid method combining Large Eddy Simulation (LES with experimental results is introduced to study the flow-structure interactions (FSI when undergoing VIVs; the vortex mode of torsional VIV on wide flat box girders is defined as “4/2S,” which is different from any other known ones. Based on the mechanism of VIV, a new approach by increasing ventilation rate of the pedestrian guardrails is proved to be effective in suppressing vertical and torsional VIVs, and it is more feasible than other control schemes. Then, the control mechanisms are deeper investigated by analyzing the evolution of vortex mode and FSI using Hybrid-LES method.

  8. Creep analysis and torsional vibration analysis of cable-stayed bridges with two edge composite girders; Nishuketa gosei kozo shachokyo no creep kaiseki to nejiri shindo kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Hoshino, M. [Nihon University, Tokyo (Japan). College of Science and Technology

    1996-07-21

    This paper describes the creep analysis and torsional vibration analysis of cable-stayed bridges with two edge composite girders. The girder is composed of the concrete slab and the steel girder. I-girders are placed at both edges of the profile. Such a type of bridge was investigated. As the stress migrates by the creep of concrete slab, it is necessary to evaluate the influence of this creep precisely in designing. In the analysis, the composite girder was expressed not by the single member, but by the binary member consisting of concrete member and steel member. Two methods were employed, i.e., method A in which both members are connected by the rigid body beam and method B in which the profile of concrete is converted into the profile of steel. The method A provided better accuracy, but the method B was often sufficient. Torsional rigidity of the open profile structure was much smaller than that of the box profile. As the torsional natural frequency was low, proper torsional vibration analysis was indispensable especially from the viewpoint of wind resistance. Two methods were employed, which utilize the vibration analysis method for general space frame structures. Results of both methods were agreed mutually, but the second method provided better calculation efficiency. 10 refs., 9 figs., 6 tabs.

  9. DESIGN AND APPLICABILITY OF STEEL AND STEEL-CONCRETE PLATE GIRDER BRIDGES WITH HYBRID SECTION

    Science.gov (United States)

    Nagai, Masatsugu; Miyashita, Takeshi; Liu, Cuiping; Inaba, Naofumi; Homma, Atsushi

    In Japan, steel and steel-concrete plate girder bridges with hybrid section, in which web plate has a relatively lower strength, have not been employed so far. From viewpoints of design method and economy, the background of situation is investigated. It is emphasized, on designing of this type of bridges and obtaining the competitiveness or superiority to conventional non-hybrid bridges, that shift of the design method from allowable stress design (ASD) method, which is conventional design method, to limit state design (LSD) method is necessary. On condition that LSD is employed, advantageous points over conventional non-hybrid girder is summarized. Shear strength of the hybrid girder is also studied, and evaluation of flexure, shear and flexure/shear interactive strength is proposed.

  10. A EVALUATION OF THE EFFECTIVE PRESTRESS ON TIMBER CONCRETE COMPOSITE GIRDER BRIDGE

    Science.gov (United States)

    Araki, Shogo

    In applying the glulam timber to the large-sized structures, the new types of connections have been developed. In presence, there are a few joint systems using steel plates and bolts. However, those systems are not always adequately satisfied with durability. Therefore, the new joint system by prestressing was developed. In Nagano prefecture, the timber-concrete composite bridge was provided as the standard design of timber bridges, and the joint system is by prestressing. In case of concrete girder, work of prestress decrease by elastic strain, creep, and etc. However, timber-concrete composite girder is not cleared numerically. In this study, we discussed the effective prestress on timber-concrete composite girder based on time-dependent of prestress checked in existing bridge, and we suggest the evaluation method of it.

  11. A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

    Science.gov (United States)

    Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

    2017-08-01

    This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler-Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges.

  12. Design Optimization and Structural Performance Evaluation of Plate Girder Bridge Constructed Using a Turn-Over Process

    Science.gov (United States)

    Eom, Gi-Ha; Kim, Sung Jae; Lee, Tae-Hee; Kim, Jang-Ho Jay

    2017-01-01

    A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of the I-type girder in two- or three- girder plate bridges is lacking. One of the most important performance improvement technologies for the I-type girder is the “preflex” method. In the preflex method, the specimen is inverted during the construction process to apply prestressed cambering to the specimen by using self-weight. However, a problem with the preflex construction method is difficulty with inverting the girder/plate system during the concrete curing process. Therefore, a new inverting system called Turn-Over (TO) wheel was proposed. Using TO wheels, wider variations to the I-type girder design can be achieved. Using this TO construction method, various cross sectional designs of girder plate systems can be considered due to its easiness in inverting the girder/plate system. In this study, the location of concrete confinement sections between the steel I-beams and concrete plates was varied in an I-girder cross-sectional design. Design parameters included effective height, flange thickness, flange width, confining concrete section width, etc. From this study, the optimum cross-sectional design of the I-girder/concrete plate system was achieved. Then, a single 20 m TO girder/plate system and two 20 m TO girder bridges were constructed and tested to evaluate their performance. From the test, failure behavior, load carrying capacity, crack pattern, etc., are obtained. The results are discussed in detail in this paper. PMID:28772644

  13. Design Optimization and Structural Performance Evaluation of Plate Girder Bridge Constructed Using a Turn-Over Process

    Directory of Open Access Journals (Sweden)

    Gi-Ha Eom

    2017-03-01

    Full Text Available A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of the I-type girder in two- or three- girder plate bridges is lacking. One of the most important performance improvement technologies for the I-type girder is the “preflex” method. In the preflex method, the specimen is inverted during the construction process to apply prestressed cambering to the specimen by using self-weight. However, a problem with the preflex construction method is difficulty with inverting the girder/plate system during the concrete curing process. Therefore, a new inverting system called Turn-Over (TO wheel was proposed. Using TO wheels, wider variations to the I-type girder design can be achieved. Using this TO construction method, various cross sectional designs of girder plate systems can be considered due to its easiness in inverting the girder/plate system. In this study, the location of concrete confinement sections between the steel I-beams and concrete plates was varied in an I-girder cross-sectional design. Design parameters included effective height, flange thickness, flange width, confining concrete section width, etc. From this study, the optimum cross-sectional design of the I-girder/concrete plate system was achieved. Then, a single 20 m TO girder/plate system and two 20 m TO girder bridges were constructed and tested to evaluate their performance. From the test, failure behavior, load carrying capacity, crack pattern, etc., are obtained. The results are discussed in detail in this paper.

  14. Design Optimization and Structural Performance Evaluation of Plate Girder Bridge Constructed Using a Turn-Over Process.

    Science.gov (United States)

    Eom, Gi-Ha; Kim, Sung Jae; Lee, Tae-Hee; Kim, Jang-Ho Jay

    2017-03-13

    A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of the I-type girder in two- or three- girder plate bridges is lacking. One of the most important performance improvement technologies for the I-type girder is the "preflex" method. In the preflex method, the specimen is inverted during the construction process to apply prestressed cambering to the specimen by using self-weight. However, a problem with the preflex construction method is difficulty with inverting the girder/plate system during the concrete curing process. Therefore, a new inverting system called Turn-Over (TO) wheel was proposed. Using TO wheels, wider variations to the I-type girder design can be achieved. Using this TO construction method, various cross sectional designs of girder plate systems can be considered due to its easiness in inverting the girder/plate system. In this study, the location of concrete confinement sections between the steel I-beams and concrete plates was varied in an I-girder cross-sectional design. Design parameters included effective height, flange thickness, flange width, confining concrete section width, etc. From this study, the optimum cross-sectional design of the I-girder/concrete plate system was achieved. Then, a single 20 m TO girder/plate system and two 20 m TO girder bridges were constructed and tested to evaluate their performance. From the test, failure behavior, load carrying capacity, crack pattern, etc., are obtained. The results are discussed in detail in this paper.

  15. Development of Embedded EM Sensors for Estimating Tensile Forces of PSC Girder Bridges.

    Science.gov (United States)

    Kim, Junkyeong; Kim, Ju-Won; Lee, Chaggil; Park, Seunghee

    2017-08-30

    The tensile force of pre-stressed concrete (PSC) girders is the most important factor for managing the stability of PSC bridges. The tensile force is induced using pre-stressing (PS) tendons of a PSC girder. Because the PS tendons are located inside of the PSC girder, the tensile force cannot be measured after construction using conventional NDT (non-destructive testing) methods. To monitor the induced tensile force of a PSC girder, an embedded EM (elasto-magnetic) sensor was proposed in this study. The PS tendons are made of carbon steel, a ferromagnetic material. The magnetic properties of the ferromagnetic specimen are changed according to the induced magnetic field, temperature, and induced stress. Thus, the tensile force of PS tendons can be estimated by measuring their magnetic properties. The EM sensor can measure the magnetic properties of ferromagnetic materials in the form of a B (magnetic density)-H (magnetic force) loop. To measure the B-H loop of a PS tendon in a PSC girder, the EM sensor should be embedded into the PSC girder. The proposed embedded EM sensor can be embedded into a PSC girder as a sheath joint by designing screw threads to connect with the sheath. To confirm the proposed embedded EM sensors, the experimental study was performed using a down-scaled PSC girder model. Two specimens were constructed with embedded EM sensors, and three sensors were installed in each specimen. The embedded EM sensor could measure the B-H loop of PS tendons even if it was located inside concrete, and the area of the B-H loop was proportionally decreased according to the increase in tensile force. According to the results, the proposed method can be used to estimate the tensile force of unrevealed PS tendons.

  16. Buffeting Response of Suspension Bridge Girder with Separate Control Flaps

    DEFF Research Database (Denmark)

    Huynh, Truc; Thoft-Christensen, Palle

    is of interest. The RMS response is determined on the basis of the equation of motion, which is formulated stochastically according to the wind random turbulence components. It is further assumed that the sum of the motion-induced forces and the buffeting-induced forces from the girder and the flaps is computed...

  17. Strain-Based Evaluation of a Steel Through-Girder Railroad Bridge

    OpenAIRE

    Daumueller, Andrew N.; Jáuregui, David V.

    2012-01-01

    In the state of New Mexico (USA), passenger rail began in 2008 between Belen and Santa Fe on the Rail Runner, following the acquisition of about 100 miles of existing rail and related infrastructure. Many of the bridges on this route are over 100 years old and contain fatigue prone details. This study focuses on a steel through-girder bridge along this corridor. To accurately evaluate these structures for load carrying capacity and fatigue, an accurate analytical model is required. Accordingl...

  18. Temperature effect on hybrid damage monitoring of PSC girder bridges by using acceleration and impedance signatures

    Science.gov (United States)

    Hong, Dong-Soo; Park, Jae-Hyung; Kim, Jeong-Tae; Na, Won-Bae

    2009-03-01

    Acceleration and impedance signatures extracted from a structure are appealing features for a prompt diagnosis on structural condition since those are relatively simple to measure and utilize. However, the feasibility of using them for damage monitoring is limited when their changes go undisclosed due to uncertain temperature conditions, particularly for large structures. In this study, temperature effect on hybrid damage monitoring of prestress concrete (PSC) girder bridges is presented. In order to achieve the objective, the following approaches are implemented. Firstly, a hybrid monitoring algorithm using acceleration and impedance signatures is proposed. The hybrid monitoring algorithm mainly consists of three sequential phases: 1) the global occurrence of damage is alarmed by monitoring changes in acceleration features, 2) the type of damage is identified as either prestress-loss or flexural stiffness-loss by identifying patterns of impedance features, 3) the location and the extent of damage are estimated from damage index method using natural frequency and mode shape changes. Secondly, changes in acceleration and impedance signatures were investigated under various temperature conditions on a laboratory-scaled PSC girder model. Then the relationship between temperatures and those signatures is analyzed to estimate and a set of empirical correlations that will be utilized for the damage alarming and classification of PSC girder bridges. Finally, the feasibility of the proposed algorithm is evaluated by using a lab-scaled PSC girder bridge for which acceleration and impedance signatures were measured for several damage scenarios under uncertain temperature conditions.

  19. Prediction of Fatigue Life of a Continuous Bridge Girder Based on Vehicle Induced Stress History

    Directory of Open Access Journals (Sweden)

    V.G. Rao

    2003-01-01

    Full Text Available The fatigue damage assessment of bridge components by conducting a full scale fatigue testing is often prohibitive. A need, therefore, exists to estimate the fatigue damage in bridge components by a simulation of bridge-vehicle interaction dynamics due to the action of the actual traffic. In the present paper, a systematic method has been outlined to find the fatigue damage in the continuous bridge girder based on stress range frequency histogram and fatigue strength parameters of the bridge materials. Vehicle induced time history of maximum flexural stresses has been obtained by Monte Carlo simulation process and utilized to develop the stress range frequency histogram taking into consideration of the annual traffic volume. The linear damage accumulation theory is then applied to calculate cumulative damage index and fatigue life of the bridge. Effect of the bridge span, pavement condition, increase of vehicle operating speed, weight and suspension characteristics on fatigue life of the bridge have been examined.

  20. Shear Behavior of Corrugated Steel Webs in H Shape Bridge Girders

    Directory of Open Access Journals (Sweden)

    Qi Cao

    2015-01-01

    Full Text Available In bridge engineering, girders with corrugated steel webs have shown good mechanical properties. With the promotion of composite bridge with corrugated steel webs, in particular steel-concrete composite girder bridge with corrugated steel webs, it is necessary to study the shear performance and buckling of the corrugated webs. In this research, by conducting experiment incorporated with finite element analysis, the stability of H shape beam welded with corrugated webs was tested and three failure modes were observed. Structural data including load-deflection, load-strain, and shear capacity of tested beam specimens were collected and compared with FEM analytical results by ANSYS software. The effects of web thickness, corrugation, and stiffening on shear capacity of corrugated webs were further discussed.

  1. Acoustic emission testing of in-service conventionally reinforced concrete deck girder superstructures on highway bridges : final report.

    Science.gov (United States)

    2008-09-01

    Three reports were produced from research sponsored by the Oregon Department of Transportation on acoustic emission (AE). The first describes the evaluation of AE techniques applied to two reinforced concrete (RC) bridge girders, which were loaded to...

  2. Flexural and Shear Behavior of FRP Strengthened AASHTO Type Concrete Bridge Girders

    Directory of Open Access Journals (Sweden)

    Nur Yazdani

    2016-01-01

    Full Text Available Fiber-reinforced polymers (FRP are being increasingly used for the repair and strengthening of deteriorated or unsafe concrete structures, including structurally deficient concrete highway bridges. The behavior of FRP strengthened concrete bridge girders, including failure modes, failure loads, and deflections, can be determined using an analytical finite element modeling approach, as outlined in this paper. The differences in flexural versus shear FRP strengthening and comparison with available design guidelines are also beneficial to design professionals. In this paper, a common AASHTO type prestressed concrete bridge girder with FRP wrapping was analyzed using the ANSYS FEM software and the ACI analytical approach. Both flexural and shear FRP applications, including vertical and inclined shear strengthening, were examined. Results showed that FRP wrapping can significantly benefit concrete bridge girders in terms of flexure/shear capacity increase, deflection reduction, and crack control. The FRP strength was underutilized in the section selected herein, which could be addressed through decrease of the amount of FRP and prestressing steel used, thereby increasing the section ductility. The ACI approach produced comparable results to the FEM and can be effectively and conveniently used in design.

  3. Sealing of Cracks on Florida Bridge Decks with Steel Girders

    Science.gov (United States)

    2012-08-01

    One of the biggest problems affecting bridges is the transverse cracking and deterioration of concrete bridge decks. The causes of early age cracking are primarily attributed to plastic shrinkage, temperature effects, autogenous shrinkage, and drying...

  4. Numerical analysis of dynamic response of vehicle–bridge coupled system on long-span continuous girder bridge

    Directory of Open Access Journals (Sweden)

    Lipeng An

    2016-07-01

    Full Text Available To systematically study the vehicle–bridge coupled dynamic response and its change rule with different parameters, a vehicle model with seven degrees of freedom was built and the total potential energy of vehicle space vibration system was deduced. Considering the stimulation of road roughness, the dynamic response equation of vehicle–bridge coupled system was established in accordance with the elastic system principle of total potential energy with stationary value and the “set-in-right-position” rule. On the basis of the self-compiled Fortran program and bridge engineering, the dynamic response of long-span continuous girder bridge under vehicle load was studied. This study also included the calculation of vehicle impact coefficient, evaluation of vibration comfort, and analysis of dynamic response parameters. Results show the impact coefficient changes with lane number and is larger than the value calculated by the “general code for design of highway bridges and culverts (China”. The Dieckmann index of bridge vibration is also related to lane number, and the vibration comfort evaluation is good in normal conditions. The relevant conclusions from parametric analyses have practical significance to dynamic design and daily operation of long-span continuous girder bridges in expressways. Safety and comfort are expected to improve significantly with further control of the vibration of vehicle–bridge system.

  5. Performance of Bridge Decks and Girders with Lightweight Aggregate Concrete, v. 2 of 2

    OpenAIRE

    Ramirez, J.A. [UNESP; Olek, J.; Rolle, Eric Joseph; Malone, Brian Joseph

    2000-01-01

    Structural lightweight concrete is a very versatile material and Haydite and Minergy lightweight aggregates can be utilized in the mixture development of concrete for use in girders and decks in bridges. More widespread use of lightweight aggregates (LWA) would result in savings in construction cost due to considerable dead load reduction. The materials phase of this research study evaluated the fresh concrete properties (slump, unit weight, and air content), the mechanical properties of ...

  6. Research on the Key Technology of Hinge Joint Diseases Treatment without Traffic Interruption for Plate Girder Bridge

    Directory of Open Access Journals (Sweden)

    Xun Jingchuan

    2015-01-01

    Full Text Available The plate girder bridge accounts for a large proportion of bridge types for its advantages of simple structure and convenience in construction. However, during the service stage, it is easy to suffer the hinge joint diseases, which badly weaken the integral rigidity of superstructure and affect the operation safety of the bridge. This paper presents a treatment technology for hinge joint diseases without interrupting traffic, and the main operation steps and key points of the technology are summarized. Through an example of the reinforcement of a plate girder bridge, the deformation data before and after the reinforcement is measured and compared, which verifies the effectiveness of the method.

  7. A Study on the Dynamic Interaction between Three-Axle Vehicle and Continuous Girder Bridge with Consideration of Braking Effects

    Directory of Open Access Journals (Sweden)

    Xuan-Toan Nguyen

    2017-01-01

    Full Text Available Continuous girder bridges become increasingly popular because of the rapid development of highway throughout the world. Most of previous researches on vibration analysis of a multispan continuous bridge subject to complex traffic loading and vehicle dynamic interaction focus on the girder displacement not considering braking effects. In current literature, few studies have discussed the effects of braking on continuous girder bridges. In this study, we employ the finite element method (FEM to investigate the dynamic response of continuous girder bridge due to three-axle vehicle. Vertical reaction forces of axles that change with time make bending vibration of girder increase significantly. The braking in the first span is able to create response in other spans. In addition, the dynamic impact factors are investigated by both FEM and experiments on a real bridge structure. The results of this study extend the current understanding of the bridge dynamic behaviors and can be used as additional references for bridge codes by practicing engineers.

  8. Statistical determination of significant curved I-girder bridge seismic response parameters

    Science.gov (United States)

    Seo, Junwon

    2013-06-01

    Curved steel bridges are commonly used at interchanges in transportation networks and more of these structures continue to be designed and built in the United States. Though the use of these bridges continues to increase in locations that experience high seismicity, the effects of curvature and other parameters on their seismic behaviors have been neglected in current risk assessment tools. These tools can evaluate the seismic vulnerability of a transportation network using fragility curves. One critical component of fragility curve development for curved steel bridges is the completion of sensitivity analyses that help identify influential parameters related to their seismic response. In this study, an accessible inventory of existing curved steel girder bridges located primarily in the Mid-Atlantic United States (MAUS) was used to establish statistical characteristics used as inputs for a seismic sensitivity study. Critical seismic response quantities were captured using 3D nonlinear finite element models. Influential parameters from these quantities were identified using statistical tools that incorporate experimental Plackett-Burman Design (PBD), which included Pareto optimal plots and prediction profiler techniques. The findings revealed that the potential variation in the influential parameters included number of spans, radius of curvature, maximum span length, girder spacing, and cross-frame spacing. These parameters showed varying levels of influence on the critical bridge response.

  9. 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.

  10. Acoustic emission techniques applied to conventionally reinforced concrete bridge girders.

    Science.gov (United States)

    2008-09-01

    Reinforced concrete (RC) bridges generally operate at service-level loads except during discrete overload events that can reduce the integrity of the structure by initiating concrete cracks, widening or extending of existing concrete cracks, as well ...

  11. Review of Elastic Analysis of Box Girder Bridges | Ezeokpube ...

    African Journals Online (AJOL)

    Nigerian Journal of Technology. Journal Home · ABOUT · Advanced Search · Current Issue · Archives · Journal Home > Vol 34, No 1 (2015) >. Log in or Register to get access to full text downloads. Username, Password, Remember me, or Register · Download this PDF file. The PDF file you selected should load here if your ...

  12. Strain-Based Evaluation of a Steel Through-Girder Railroad Bridge

    Directory of Open Access Journals (Sweden)

    Andrew N. Daumueller

    2012-01-01

    Full Text Available In the state of New Mexico (USA, passenger rail began in 2008 between Belen and Santa Fe on the Rail Runner, following the acquisition of about 100 miles of existing rail and related infrastructure. Many of the bridges on this route are over 100 years old and contain fatigue prone details. This study focuses on a steel through-girder bridge along this corridor. To accurately evaluate these structures for load carrying capacity and fatigue, an accurate analytical model is required. Accordingly, four models were developed to study the sensitivity of a bridge in New Mexico to floor-system connection fixity and the ballast. A diagnostic load test was also performed to evaluate the accuracy of the finite-element models at locations of maximum moments. Comparisons between the simulated and measured bridge response were made based on strain profiles, peak strains, and Palmgren-Miner’s sums. It was found that the models including the ballast were most accurate. In most cases, the pinned ended models were closer to the measured strains. The floor beams and girders were relatively insensitive to the ballast and end conditions of the floor-system members, whereas the stringers were sensitive to the modeling of the ballast.

  13. Shear and shear friction of ultra-high performance concrete bridge girders

    Science.gov (United States)

    Crane, Charles Kennan

    Ultra-High Performance Concrete (UHPC) is a new class of concrete characterized by no coarse aggregate, steel fiber reinforcement, low w/c, low permeability, compressive strength exceeding 29,000 psi (200 MPa), tensile strength ranging from 1,200 to 2,500 psi (8 to 17 MPa), and very high toughness. These properties make prestressed precast UHPC bridge girders a very attractive replacement material for steel bridge girders, particularly when site demands require a comparable beam depth to steel and a 100+ year life span is desired. In order to efficiently utilize UHPC in bridge construction, it is necessary to create new design recommendations for its use. The interface between precast UHPC girder and cast-in-place concrete decks must be characterized in order to safely use composite design methods with this new material. Due to the lack of reinforcing bars, all shear forces in UHPC girders have to be carried by the concrete and steel fibers. Current U.S. codes do not consider fiber reinforcement in calculating shear capacity. Fiber contribution must be accurately accounted for in shear equations in order to use UHPC. Casting of UHPC may cause fibers to orient in the direction of casting. If fibers are preferentially oriented, physical properties of the concrete may also become anisotropic, which must be considered in design. The current research provides new understanding of shear and shear friction phenomena in UHPC including: (1) Current AASHTO codes provide a non-conservative estimate of interface shear performance of smooth UHPC interfaces with and without interface steel. (2) Fluted interfaces can be created by impressing formliners into the surface of plastic UHPC. AASHTO and ACI codes for roughened interfaces are conservative for design of fluted UHPC interfaces.(3) A new equation for the calculation of shear capacity of UHPC girders is presented which takes into account the contribution of steel fiber reinforcement. (4) Fibers are shown to preferentially

  14. Development of improved connection details for adjacent prestressed member bridges.

    Science.gov (United States)

    2017-06-01

    Adjacent prestressed member girder bridges are economical systems for short spans and generally come in two types: adjacent box beam bridges and adjacent voided slab bridges. Each type provides the advantages of having low clearances because of their...

  15. Application of Concrete Segment Panels for Reduction of Torsional Vibration Responses of Girder Bridges

    Directory of Open Access Journals (Sweden)

    Kwark Jong-Won

    2015-01-01

    Full Text Available The dynamic flexural behaviour of railway bridges is influenced by the torsional behaviour, and the flexural response tends to be amplified as the flexural natural frequency (the 1st vibrational mode and torsional frequency (the 2nd vibrational mode are adjoining. To avoid this phenomenon, the installation of concrete segment panels was considered for the reinforcement of torsional stiffness by connecting bottom flanges between girders. This alternative can increase the torsional stiffness by providing the restraint in torsional vibration and reduce the influence of torsional behaviour on the amplification of flexural responses. This study investigates the effect of the concrete segment panels on the control of torsional dynamic responses and on the increment of torsional frequency. The excitation tests on a full-size bridge specimen with 30 m span length were conducted with respect to the installation length of concrete panels up to 7 m from each ends. The results show that the installation of concrete segment panel augments the torsional frequency up to 22 % while the flexural frequency keeps its original value. It is concluded that the dynamic behaviour of girder bridges can be controlled by the adjustment of installation length of concrete panels, thereby reducing the torsional responses.

  16. Research on the Key Technology of Hinge Joint Diseases Treatment without Traffic Interruption for Plate Girder Bridge

    OpenAIRE

    Xun Jingchuan; Xiang Hongwei; Peng Jingrong

    2015-01-01

    The plate girder bridge accounts for a large proportion of bridge types for its advantages of simple structure and convenience in construction. However, during the service stage, it is easy to suffer the hinge joint diseases, which badly weaken the integral rigidity of superstructure and affect the operation safety of the bridge. This paper presents a treatment technology for hinge joint diseases without interrupting traffic, and the main operation steps and key points of the technology are s...

  17. 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.

  18. Proposal and study of a long-span composite cable-stayed bridge with new hybrid girder; Atarashii gosei kozo shuketa wo mochiita chodai fukugo shachokyo no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, K.; Hishiki, Y.; Furuichi, K. [Kajima Corp., Tokyo (Japan)

    1999-09-30

    A hybrid or mixed structure (composite structures) are a matter of increasing concern which takes in each advantage of steel and concrete. A field of bridges is no exception, with the plan and construction carried out for the new type of composite bridge, such as a composite cable-stayed bridge and a composite extra dose bridge as a long span bridge, and a composite truss bridge and a corrugated steel plate web bridge as a medium-span bridge, with technological development becoming active in this field. In such a technological trend, a hybrid two-girder structure was devised, a structure consisting of a concrete filled steel pipe for a girder and a precast (PC) floor plate for a floor board, as the girder structure of a long-span cable-stayed bridge in the subject research; also, applicability was examined using, as an example, the composite cable-stayed bridge with hybrid girders employed for the span. This paper reports the result of the analysis of the entire system, the analysis made for the purpose of examining the characteristic and the feasibility of this hybrid girder. The analysis revealed the structural feasibility of the long-span composite cable-stayed bridge using two hybrid girders of concrete-filled steel pipes thus devised. (NEDO)

  19. Full scale test of a SSP 34m box girder 1. Data report; Reinforced glass fiber/expoxy used in wind turbine blades

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Find M.; Branner, K.; Nielsen, Per H. (and others)

    2008-03-15

    This report presents the setup and result of a full-scale test of a reinforced glass fibre/epoxy box girder used in 34m wind turbine blade. The tests were performed at the Blaest test facility in August 2006. The test is an important part of a research project established in cooperation between Risoe DTU, the National Laboratory for Sustainable Energy at the Technical University of Denmark -, SSP-Technology A/S and Blaest (Blade test centre A/S) and it has been performed as a part of Find Moelholt Jensen's PhD study. This report contains the complete test data for the final test, in which the box girder was loaded until failure. A comprehensive description of the test setup is given. This report deals only with tests and results. There are no conclusions on the data in this report, but references are given to publications, where the data are used and compared with FEM etc. Various kinds of measuring equipment have been used during these tests: acoustic emission, 330 strain gauges, 24 mechanical displacement devices and two optical deformation measuring systems. The mechanical displacement devices measured both global (absolute) and local (relative) deflection and the optical systems measured surface deformation. A prediction was made on the location of the failure of the girder. At this location the majority of the measuring equipment was concentrated. The prediction was proved to be correct and valuable information of the behaviour of the box girder prior to failure was obtained. The experimental investigation consisted of the following load configurations: -Flapwise bending -Torsion Ultrasonic scanning of the box girder was performed before, during and after the test the box girder. This was done to investigate whether the girder was damaged by the load or imperfection (productions defects) growth. (au)

  20. Construction of stiffening girder for Akashi straits bridge. Installation with use of latest bridging technology; Akashi kaikyo ohashi hoko keta kasetsu koji. Saishin kakyo gijutsu wo kushishite kasetsu

    Energy Technology Data Exchange (ETDEWEB)

    Oe, S. [Honshu-Shikoku Bridge Authority, Tokyo (Japan)

    1996-05-25

    The Akashi straits bridge is the Kobe-Naruto route of the bridge connecting Honshu and Shikoku; the bridge links Kobe in Hyogo prefecture with Awaji Island and, when completed, it will be a 3-span 2-hinge suspension bridge with the longest center effective span in the world. This report centers on the outline of the construction of stiffening girders for the Akashi straits bridge and especially on the characteristics of the engineering method newly employed. As the method of installing the stiffening girders, an overhang installation of face bars was employed which was a time-tested method. As the installing direction of the side spans, it was decided to install them from the anchorage to the tower. At the beginning, six large block installations were performed. A special balance was developed for the installation of short hanger parts for the purpose of enhancing safety and reduction in the process. A rubber-tired transporting truck was adopted for transporting members of framework on the bridge. GPS survey was used as a method for surveying the configuration. The subject engineering method was based on the construction of suspension bridge stiffening trusses in the past Honshu-Shikoku connecting bridge and reinforced with the improvements as above. Since the bridge is in the middle of construction, a subsequent report will hopefully be made on the actual results of the installation and the spanning after the closure. 8 figs., 2 tabs.

  1. Mathematical Modeling for Lateral Displacement Induced by Wind Velocity Using Monitoring Data Obtained from Main Girder of Sutong Cable-Stayed Bridge

    Directory of Open Access Journals (Sweden)

    Gao-Xin Wang

    2014-01-01

    Full Text Available Based on the health monitoring system installed on the main span of Sutong Cable-Stayed Bridge, GPS displacement and wind field are real-time monitored and analyzed. According to analytical results, apparent nonlinear correlation with certain discreteness exists between lateral static girder displacement and lateral static wind velocity; thus time series of lateral static girder displacement are decomposed into nonlinear correlation term and discreteness term, nonlinear correlation term of which is mathematically modeled by third-order Fourier series with intervention of lateral static wind velocity and discreteness term of which is mathematically modeled by the combined models of ARMA(7,4 and EGARCH(2,1. Additionally, stable power spectrum density exists in time series of lateral dynamic girder displacement, which can be well described by the fourth-order Gaussian series; thus time series of lateral dynamic girder displacement are mathematically modeled by harmonic superposition function. By comparison and verification between simulative and monitoring lateral girder displacements from September 1 to September 3, the presented mathematical models are effective to simulate time series of lateral girder displacement from main girder of Sutong Cable-Stayed Bridge.

  2. Effects of bottom bracings on torsional dynamic characteristics of horizontally curved twin I-girder bridges with different curvatures

    Science.gov (United States)

    Awall, Md. Robiul; Hayashikawa, Toshiro; Matsumoto, Takashi; He, Xingwen

    2012-03-01

    Curved twin I-girder bridges (CTIGBs) have low torsional stiffness that makes them vulnerable to dynamic loads. This study investigates the effects of bottom bracings on the torsional dynamic characteristics of CTIGBs. Five types of bottom bracings are designed to investigate their effects on the dynamic characteristics of CTIGBs with different curvatures under free and forced vibrations. To perform numerical investigations, three-dimensional (3-D) finite element (FE) bridge and vehicle models are established using commercial ANSYS code, and then a vehicle-bridge interaction analysis approach is proposed. Road roughness profiles generated from power spectral density and cross spectral functions are also taken into account in the analyses. The numerical results show that torsional frequencies increase significantly after providing bottom bracings, and the increasing rate depends on the type of bottom bracings and their locations of installation. Bottom bracings can act as load transmitting members from one main girder to the others. Large negative bearing forces that have occurred in bridges with small radii of curvatures can be remarkably reduced by providing bottom bracing systems. It is found that the performances of several bottom bracing systems are effective in improving the torsional dynamic characteristics of the bridges in this study.

  3. Finite element model updating of multi-span steel-arch-steel-girder bridges based on ambient vibrations

    Science.gov (United States)

    Hou, Tsung-Chin; Gao, Wei-Yuan; Chang, Chia-Sheng; Zhu, Guan-Rong; Su, Yu-Min

    2017-04-01

    The three-span steel-arch-steel-girder Jiaxian Bridge was newly constructed in 2010 to replace the former one that has been destroyed by Typhoon Sinlaku (2008, Taiwan). It was designed and built to continue the domestic service requirement, as well as to improve the tourism business of the Kaohsiung city government, Taiwan. This study aimed at establishing the baseline model of Jiaxian Bridge for hazardous scenario simulation such as typhoons, floods and earthquakes. Necessities of these precaution works were attributed to the inherent vulnerability of the sites: near fault and river cross. The uncalibrated baseline bridge model was built with structural finite element in accordance with the blueprints. Ambient vibration measurements were performed repeatedly to acquire the elastic dynamic characteristics of the bridge structure. Two frequency domain system identification algorithms were employed to extract the measured operational modal parameters. Modal shapes, frequencies, and modal assurance criteria (MAC) were configured as the fitting targets so as to calibrate/update the structural parameters of the baseline model. It has been recognized that different types of structural parameters contribute distinguishably to the fitting targets, as this study has similarly explored. For steel-arch-steel-girder bridges in particular this case, joint rigidity of the steel components was found to be dominant while material properties and section geometries relatively minor. The updated model was capable of providing more rational elastic responses of the bridge superstructure under normal service conditions as well as hazardous scenarios, and can be used for manage the health conditions of the bridge structure.

  4. Buckling strength of tapered bridge girders under combined shear and bending

    Directory of Open Access Journals (Sweden)

    Metwally Abu-Hamd

    2016-08-01

    Full Text Available This paper represents the finite element results for the local buckling of tapered plate girders subjected to combine pure bending and shear stresses. An idealized model is developed representing the loading of the tapered panel that generates uniform normal stresses due to flexure, or uniform and constant shear stresses in the case of shear. Eigen-value analysis was performed for several tapered web plate girders that have different geometric parameters. A parametric study is made to reduce the FE model size showing the effect of decreasing the tapered panel adjacent straight panels, maintaining the same result accuracy as a complete girder model. The combined buckling capacity of bending and shear is determined by applying all possible load pattern combinations, together with different interaction ratios. An analysis study is presented to investigate the effect of the tapering angle on the combined bending–shear capacity of the girder. The study also includes the effect of the flange and web slenderness on the local buckling of the girder. Considering residual stresses as part of the loading stresses, the analysis procedure is repeated for some cases, and the effect of combining of the residual stresses together with the external loads is found. Empirical approximate formulae are given to estimate the combined flexure–shear buckling resistance of the tapered girder safely.

  5. A new method for detection of fatigue cracking in steel bridge girders using self-powered wireless sensors

    Science.gov (United States)

    Hasni, Hassene; Alavi, Amir H.; Jiao, Pengcheng; Lajnef, Nizar

    2017-04-01

    Development of fatigue cracking is affecting the structural performance of many of welded steel bridges in the United States. This paper presents a support vector machine (SVM) method for the detection of distortion-induced fatigue cracking in steel bridge girders based on the data provided by self-powered wireless sensors (SWS). The sensors have a series of memory gates that can cumulatively record the duration of the applied strain at a specific threshold level. Each sensor output has been characterized by a Gaussian cumulative density function. For the analysis, extensive finite element simulations were carried out to obtain the structural response of an existing highway steel bridge girder (I-96/M- 52) in Webberville, Michigan. The damage states were defined based on the length of the crack. Initial damage indicator features were extracted from the sensor output distribution at different data acquisition nodes. Subsequently, the SVM classifier was developed to identify multiple damage states. A data fusion model was proposed to increase the classification performance. The results indicate that the models have acceptable detection performance, specific ally for cracks larger than 10 mm. The best classification performance was obtained using the information from a group of sensors located near the damage zone.

  6. Study on the Aerodynamic Characteristics of a Single-pylon Cable-stayed Bridge Girder by Numerical Simulation and Wind Tunnel Test

    Directory of Open Access Journals (Sweden)

    Longqi Zhang

    2014-09-01

    Full Text Available The wind induced vibration is one of the key technical problems for long-span bridge design. Therefore, a study on the aerodynamic characteristics of a single-pylon cable-stayed bridge girder is carried out in this paper. The aerostatic coefficient of the bridge girder, including both construction state and service state, is investigated by wind tunnel test with varying wind attack angle. Then based on the computational fluid dynamics (CFD method, the flow field around the bridge girder is visualized numerically. The risk of vortex-induced vibration (VIV is qualitatively evaluated by analyzing the flow features and by considering the Scruton number (Sc. Later a dynamic section model is tested in wind tunnel and the VIV phenomenon is observed subsequently. Results show that the aerodynamic stability is assured by the positive slope of the lift coefficient. The VIV response is influenced by the structural damping and the bridge accessory. The amplitude of VIV response can be lower by increasing the structural damping. The maintenance track rail of the bridge girder also does some good for suppressing the VIV as long as the track rail is located at the appropriate place.

  7. CFRP-Strengthening and Long-Term Performance of Fatigue Critical Welds of a Steel Box Girder

    Directory of Open Access Journals (Sweden)

    Roland E. Koller

    2014-02-01

    Full Text Available Empa’s research efforts in the 1990s provided evidence that a considerable increase of the fatigue strength of welded aluminum beams can be achieved by externally bonding pultruded carbon fiber reinforced polymer (CFRP laminates using rubber-toughened epoxies over the fatigue-weak welding zone on their tensile flange. The reinforcing effect obtained is determined by the stiffness of the unidirectional CFRP laminate which has twice the elastic modulus of aluminum. One can therefore easily follow that an unstressed CFRP laminate reinforcement of welded beams made of steel will not lead to a substantial increase in fatigue strength of the steel structure. This consideration led to the idea of prestressing an external reinforcement of the welded zone. The present investigation describes experimental studies to identify the adhesive system suitable for achieving high creep and fatigue strength of the prestressed CFRP patch. Experimental results (Wöhler-fields of shear-lap-specimens and welded steel beams reinforced with prestressed CFRP laminates are presented. The paper concludes by presenting a field application, the reinforcement of a steel pendulum by adhesively bonded prestressed CFRP laminates to the tensile flanges of the welded box girder. Inspections carried out periodically on this structure revealed neither prestress losses nor crack initiation after nine years of service.

  8. Field instrumentation and measured response of the I-295 cable-stayed bridge : interim report on construction measurements in deck segments.

    Science.gov (United States)

    1991-01-01

    During the construction of the I-295 cable-stayed bridge, an extensive array of mechanical strain gage points were installed in sections of the box girders, pylons, and piers. At each instrumented box girder section, five longitudinal gages were plac...

  9. Field performance of timber bridges. 11, Spearfish Creek stress-laminated box-beam bridge

    Science.gov (United States)

    J. P. Wacker; M. A. Ritter; K. Stanfill-McMillan

    The Spearfish Creek bridge was constructed in 1992 in Spearfish, South Dakota. It is a single-span, stress-laminated, box-beam superstructure. Performance of the bridge is being monitored for 5 years, beginning at installation. This report summarizes results for the first 3-1/2 years of monitoring and includes information on the design, construction, and field...

  10. Carbon-based tendons in the Dintelhaven Bridge, the Netherlands

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Grundlehner, W.B.

    2003-01-01

    In mid-2001 the final two bridges over the River Dintelhaven in the harbour area of Rotterdam were put into use. Both bridges are concrete box girder bridges and have been erected using the balanced cantilever method. In the first bridge, with a main span of about 185 m, four (external) tendons each

  11. Field performance of timber bridges. 12, Christian Hollow stress-laminated box-beam bridge

    Science.gov (United States)

    J. P. Wacker; S. C. Catherman; R. G. Winnett

    In January 1992, the Christian Hollow bridge was constructed in Steuben County, New York. The bridge is a single-span, stress-laminated box-beam superstructure that is 9.1 m long, 9.8 m wide, and 502 mm deep (30 ft long, 32 ft wide, and 19-3/4 in. deep). The performance of the bridge was continuously monitored for 28 months, beginning shortly after installation....

  12. Bottom flange reinforcement in NU I-girders.

    Science.gov (United States)

    2010-08-01

    "The 1996 edition of AASHTO Standard Specifications for Highway Bridges stated that nominal confinement reinforcement be placed to enclose prestressing steel in the bottom flange of bridge girders from girder ends to at least a distance eq changed th...

  13. Structural Health Monitoring and Time-Dependent Effects Analysis of Self-Anchored Suspension Bridge with Extra-Wide Concrete Girder

    Directory of Open Access Journals (Sweden)

    Guangpan Zhou

    2018-01-01

    Full Text Available The present work is aimed at studying the structural health status of Hunan Road Bridge, which is currently the widest concrete self-anchored suspension bridge in China. The monitoring data included the structural deformations, internal forces, and vibration characteristics from April 2015 to April 2016 were analyzed to evaluate the structural changes and safety. The influences brought by the ambient temperature changes and the dual effects composed of concrete shrinkage & creep (S&C and seasonal temperature changes were analyzed based on the measured data. The long-time effects of concrete S&C were predicted using the CEB-FIP 90 model and the age-adjusted effective modulus method based on the ANSYS beam finite element model. The measured data showed that the transverse displacements of towers were more significant than the longitudinal ones. The spatial effect of the extra-wide girder is significant, which performs as the longitudinal stresses change unevenly along the transverse direction. The seasonal ambient warming caused overall increases in girder compressive stresses, and the cooling resulted in decreases along with significant temperature gradient effects. The prediction results show that the cable anchoring positions at girder ends and tower tops will move towards the mid-span affected by concrete S&C. In terms of the middle region of mid-span girder, significant increases in longitudinal stresses of top plate and decreases in the ones of bottom plate will be caused by the significant deflection. Comprehensively, the increases in the girder compressive stresses of side-span bottom plate and mid-span top plate are worthy of attention when confronted with extreme high temperature during the bridge service life cycle.

  14. 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 analytical prediction methods. In this paper, an analytical model that departs from the strip assumption is used to describe the gust loading on a thin airfoil. A parallel is drawn between the analytical model and direct measurements of gust loading on motionless closed-box girder bridge decks. Empirical...

  15. Seismic Performance of Multi-Span RC Railway Bridges

    DEFF Research Database (Denmark)

    Georgakis, Christos; Barrau, Xavier

    2008-01-01

    Presently, there is no clear method for determining the optimal railway bridge design for a particular ground type and expected seismic intensity. Four main types of RC bridge dominate the current multi-span railway bridge design trends – the Simply Supported Beam, Continuous Box-Girder (CBG), CB...

  16. Lateral Load Distribution Factors for Military Vehicles on Multi-Girder Bridges

    National Research Council Canada - National Science Library

    Pinero, Juan

    2002-01-01

    .... Thus, use of conventional load distribution factors to rate bridges for military deployments often results in inaccurate ratings and thus unnecessarily limits mobility options for the military...

  17. Live-load distribution on glued-laminated timber girder bridges : final report : conclusions and recommendations

    Science.gov (United States)

    Fouad Fanous; Jeremy May; Terry Wipf; Michael Ritter

    2011-01-01

    Increased use of timber bridges in the U.S. transportation system has required additional research to improve the current design methodology of these bridges. For this reason, the U.S. Forest Service, Forest Products Laboratory (FPL), and the Federal Highway Administration have supported several research programs to attain the objective listed above. This report is a...

  18. Balanced Cantilever Girder Bridge Over the Danube-Black Sea Channel

    Directory of Open Access Journals (Sweden)

    Giordano Aldo

    2013-12-01

    Full Text Available This paper describes the design and construction of a “balanced cantilever girder” bridge over the Danube-Black Sea channel, characterized by a central span of 155m with two symmetrical side spans of 77.5m. The total length of the bridge, including portions of the abutments support, is 312.0m.

  19. Acoustic emission techniques applied to conventionally reinforced concrete bridge girders : final report.

    Science.gov (United States)

    2008-09-01

    Reinforced concrete (RC) bridges generally operate at service-level loads except during discrete overload events that can reduce the integrity of the structure by initiating concrete cracks, widening or extending of existing concrete cracks, as well ...

  20. Application of titanium alloy bars for strengthening reinforced concrete bridge girders (part a: shear) : final report.

    Science.gov (United States)

    2017-07-04

    Large numbers of conventionally reinforced concrete bridges (RC) were constructed during the interstate highway expansion of the 1950s and remain in the national inventory. Coincidently, deformed steel reinforcing bars were standardized. The stand...

  1. Quality control and in-service inspection technology for hybrid-composite girder bridges.

    Science.gov (United States)

    2014-08-01

    This report describes efforts to develop quality control tools and in-service inspection technologies for the fabrication and construction of Hybrid Composite Beams (HCBs). HCBs are a new bridge technology currently being evaluated by the Missouri De...

  2. Live-Load Testing Application Using a Wireless Sensor System and Finite-Element Model Analysis of an Integral Abutment Concrete Girder Bridge

    Directory of Open Access Journals (Sweden)

    Robert W. Fausett

    2014-01-01

    Full Text Available As part of an investigation on the performance of integral abutment bridges, a single-span, integral abutment, prestressed concrete girder bridge near Perry, Utah was instrumented for live-load testing. The live-load test included driving trucks at 2.24 m/s (5 mph along predetermined load paths and measuring the corresponding strain and deflection. The measured data was used to validate a finite-element model (FEM of the bridge. The model showed that the integral abutments were behaving as 94% of a fixed-fixed support. Live-load distribution factors were obtained using this validated model and compared to those calculated in accordance to recommended procedures provided in the AASHTO LRFD Bridge Design Specifications (2010. The results indicated that if the bridge was considered simply supported, the AASHTO LRFD Specification distribution factors were conservative (in comparison to the FEM results. These conservative distribution factors, along with the initial simply supported design assumption resulted in a very conservative bridge design. In addition, a parametric study was conducted by modifying various bridge properties of the validated bridge model, one at a time, in order to investigate the influence that individual changes in span length, deck thickness, edge distance, skew, and fixity had on live-load distribution. The results showed that the bridge properties with the largest influence on bridge live-load distribution were fixity, skew, and changes in edge distance.

  3. Development of guidelines for transportation of prestressed concrete girders.

    Science.gov (United States)

    2011-11-01

    "Prestressed concrete girders are an economical superstructure system for bridges. With the : advent of higher strength concretes and more effi cient cross sections, the use of long span (>100 : ft.) prestressed girders are now specifi ed. Such long ...

  4. Repair of cracked prestressed concrete girders, I-565, Huntsville, Alabama.

    Science.gov (United States)

    2011-07-01

    Wide cracks were discovered in prestressed concrete bridge girders shortly after their construction in Huntsville, Alabama. Previous investigations of these continuous-for-live-load girders revealed that the cracking resulted from restrained thermal ...

  5. Development of a smart timber bridge girder with fiber optic sensors

    Science.gov (United States)

    James Wacker; Ursula Deza; Brent M. Phares; Terry J. Wipf

    2010-01-01

    Past timber bridge evaluation and maintenance efforts in the USA have principally focused on the internal integrity of timber components using various non-destructive evaluation tools to supplement visual inspection data. This project is part of a comprehensive effort to develop smart structure concepts for improving the long-term performance, maintenance, and...

  6. Performance of streamlined bridge decks in relation to the aerodynamics of a flat plate

    DEFF Research Database (Denmark)

    Larose, Guy; Livesey, Flora M.

    1997-01-01

    The aerodynamics of three modern bridge decks are compared to the aerodynamics of a 16:1 flat plate. The comparisons are made on the basis of the analytical evaluation of the performance of each cross-section to the buffeting action of the wind. In general, the closed-box girders studied...... in this paper showed buffeting responses similar to a flat plate with the exception of the multi-box girder which performed much better aerodynamically....

  7. Evaluation on Impact Interaction between Abutment and Steel Girder Subjected to Nonuniform Seismic Excitation

    Directory of Open Access Journals (Sweden)

    Yue Zheng

    2015-01-01

    Full Text Available This paper aims to evaluate the impact interaction between the abutment and the girder subjected to nonuniform seismic excitation. An impact model based on tests is presented by taking material properties of the backfill of the abutment into consideration. The conditional simulation is performed to investigate the spatial variation of earthquake ground motions. A two-span continuous steel box girder bridge is taken as the example to analyze and assess the pounding interaction between the abutment and the girder. The detailed nonlinear finite element (FE model is established and the steel girder and the reinforced concrete piers are modeled by nonlinear fiber elements. The pounding element of the abutment is simulated by using a trilinear compression gap element. The elastic-perfectly plastic element is used to model the nonlinear rubber bearings. The comparisons of the pounding forces, the shear forces of the nonlinear bearings, the moments of reinforced concrete piers, and the axial pounding stresses of the steel girder are studied. The made observations indicate that the nonuniform excitation for multisupport bridge is imperative in the analysis and evaluation of the pounding effects of the bridges.

  8. Influence of Blasting Vibration on Young Concrete Bridge: A Case Study of Yesanhe Super Large Bridge

    Directory of Open Access Journals (Sweden)

    Ming Chen

    2017-01-01

    Full Text Available Influence of blasting vibration on young concrete structure is an important issue in the field of hydropower engineering, transportation, and so forth. Based on influence of blasting excavation on concrete pouring progress of box girder in nearby Yesanhe Super Large Bridge, which is located in Hubei Province of China, a method combining field test and numerical simulation is used to study influence of blasting vibration on young concrete super large bridge. The results show that blasting excavation of nearby Yesanhe Hydropower Station induced vibration response on Yesanhe Bridge and peak particle velocity (PPV on the bridge was quite small under test conditions. Monitoring data and numerical simulation both indicate that PPV of box girder is 1 to 4 times larger than that of pier foundation; with the extension of bridge cantilever casting section, velocity amplification factors of different parts of the box girder have different changes and duration of vibration in vertical direction increases. Three days after concrete pouring, the impact of concrete ageing on PPV and damage distribution of the bridge is not obvious. When vibration velocity of pier foundation is within 2 cm/s, the maximum tensile and compressive stress of box girder concrete are less than the tensile and compressive strength of concrete, so that blasting vibration unlikely gives impact on the safety of bridge.

  9. Study of service life of concrete girder bridge on the sea

    Directory of Open Access Journals (Sweden)

    Da Silva, T. J.

    2003-12-01

    Full Text Available The objective of this paper is to study the evolution of the failure probability of the concrete beams to estimate the service life of a sea bridge in the southeast region of Brazil. The mechanism of deterioration analyzed in the study was the corrosion of the reinforcing bars. The models utilized for that are related with the carbonation and penetration of chlorides. Tests have been carried out for the characterization of the main variables used in the calculations and in the deterioration models. The information was completed with the control data obtained during the construction. It was obtained the functions of conjoined density of the variables through simulation. The method FORM was used to estimate the failure probability. For an adopted failure probability of 10-3 cracking due the corrosion products, the obtained values for the service lives for the 25 analyzed beams were in a range of 25 up to 70 years.

    El objetivo de este trabajo es presentar el estudio de la evolución de la probabilidad de fallo de las vigas de hormigón posibilitando estimar la vida útil de un puente sobre el mar en la región sureste de Brasil. El mecanismo de deterioro analizado en el estudio ha sido la corrosión de las armaduras. Los modelos utilizados para ello están relacionados con la carbonatación y penetración de cloruros. Se han realizado diferentes ensayos para la caracterización de las principales variables empleadas en los cálculos y en los mecanismos de deterioro. Las informaciones han sido completadas con los datos de control obtenidos durante la construcción. Mediante simulación se obtuvieron las funciones de densidad conjunta de las variables. Se usa el método FORM para estimar la probabilidad de fallo. Adoptándose una probabilidad de fallo de 10-3 para la fisuración debido a los productos de corrosión, los valores obtenidos para las vidas útiles para las 25 vigas analizadas están en un rango de 25 hasta 70

  10. Vibration and Buckling of Web Plate of the Plate Girder

    OpenAIRE

    高橋, 和雄; 呉, 明強; 中澤, 聡志; 筑紫, 宏之

    1998-01-01

    The vibration and buckling of the web of the plate girder are studied in this paper. The small deflection theory of the thin plate is used. The finite strip method is employed to solve vibration and buckling of the plate girder. Natural frequenies of buckling properties are shown for various plate girder bridges.

  11. Design and performance of self-consolidating concrete for connecting precast concrete deck panels and bridge I-girders.

    Science.gov (United States)

    2014-08-01

    Existing full-depth precast concrete deck systems use either open channels or pockets to accommodate the shear connectors of supporting girders for achieving composite systems. The use of open channels or pockets requires cast-in-place concrete/grout...

  12. Design and research on the first polish FRP composite road bridge

    Directory of Open Access Journals (Sweden)

    Siwowski Tomasz

    2015-12-01

    Full Text Available The main goal of the research project was to develop and demonstrate the first Polish FRP composite road bridge, starting from concept design and material research, and going thru manufacturing technique selection, detailed FEM analysis and structural testing of elements. The R&D project comprises also the proof test of the completed bridge as well as structural monitoring in exploitation period. The objective of the paper is the description of the bridge and its structural solutions, i.e. FRP box girders and lightweight concrete deck slab acting compositely. Further the FEM analysis of the girder and the bridge span made on design stage has been presented. The VARTM manufacturing technique was used for girders production. Its main steps have been also presented. Finally the research on the new FRP box girder with LRC slab (hybrid girder has been briefly showed. The full scale prototype girder with the total length of 22 m was tested to evaluate its carrying capacity, modes of failure, basic dynamic parameters as well as overall behaviour under ultimate static load. The FRP girder met the prescribed serviceability and safety criteria. The FEM model of the girder was validated against testing results and was further used for bridge design. Thanks to R&D project the first Polish FRP bridge is likely to be built late autumn 2015. The output of the research project gives a very promising future for the FRP composite bridge application. The research works showed in the paper have been partially financed by the Polish National Centre for Research and Development in the frame of the research project “ComBridge” (www.com-bridge.pl.

  13. Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

    Directory of Open Access Journals (Sweden)

    Hatem M. Seliem

    2015-04-01

    The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.

  14. Finite Element Analysis of Deep Wide-Flanged Pre-stressed Girders : Draft Final Report

    Science.gov (United States)

    2011-06-01

    Hundreds of prestressed concrete girders are used each year for building bridges in Wisconsin. : The prestress transfer from the prestressing strands to concrete takes place at the girder ends. : Characteristic cracks form in this end region during o...

  15. Experimental validation of bracing recommendations for long-span concrete girders : final report.

    Science.gov (United States)

    2012-12-01

    During bridge construction, flexible support conditions provided by steel-reinforced neoprene bearing pads supporting precast, prestressed concrete girders may allow the girders to become unstable, rolling about an axis parallel to the span of the gi...

  16. Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : final report.

    Science.gov (United States)

    2016-10-01

    The objective of this study was to determine the economic impact of designing pre-tensioned prestressed concrete beam (PPCB) : bridges utilizing the continuity developed in the bridge deck as opposed to the current Iowa Department of Transportation (...

  17. Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : tech transfer summary.

    Science.gov (United States)

    2016-10-01

    The objective of this study was to determine the economic impact of : designing pre-tensioned prestressed concrete beam (PPCB) bridges : utilizing the continuity developed in the bridge deck as opposed to the : current Iowa Department of Transportati...

  18. Damage Identification for Prestressed Adjacent Box-Beam Bridges

    Directory of Open Access Journals (Sweden)

    Kenneth K. Walsh

    2014-01-01

    Full Text Available Structural health monitoring (SHM has gained considerable attention as a tool for monitoring the health of civil infrastructure. For bridge infrastructure, previous methods have focused on the detection of localized damage through modal parameters extracted from the longitudinal direction of the structure. This paper investigates a new damage detection method based on the change in the first vertical mode extracted from the transverse direction of the bridge. The mode is determined through application of modal curve fitting to frequency response functions (FRFs that are formed using vertical response data obtained in the direction perpendicular to the bridge’s longitudinal axis. Using this method, both local damage and global damage in the bridge reveal themselves as having a localized effect on the bridge response. Furthermore, damage is revealed in such a way that it enables differentiation of the damage types. To demonstrate the effectiveness of the method, modal parameters were extracted from acceleration data obtained from a finite element model of a full bridge. Analysis of the modal parameters showed that the proposed approach could not only detect both local and global bridge damage, but could also differentiate between damage types using only one mode shape. The proposed method was compared to a previously developed SHM method.

  19. Steel plate girder diaphragm and cross-bracing loads : [summary].

    Science.gov (United States)

    2014-05-01

    Steel bridge designs are integrated so that every : component contributes to structural integrity, : including the concrete bridge deck, which : connects to the girders and makes the structure : rigid. Until the deck is completed and the : concrete i...

  20. Forensic testing of post tensioned concrete girders.

    Science.gov (United States)

    2014-07-01

    Recently, two separate Interstate 15 highway bridges over the 400 South roadway in Orem, Utah were demolished : after 50 years of service. A total of four post-tensioned girders were salvaged from both the north-bound and : south-bound bridge. A seri...

  1. Development of a new-type super-long bridge; Chochotaikyo ni tekigoshita shinkeishiki kyoryo no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, K.; Shimodoio, H.; Saito, T.; Nogami, C.; Oryu, T.; Morikawa, M. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1998-12-20

    In order to realize large strait-crossing projects in the near future, it is necessary to develop a new type of super-long span bridge, which has a superior aerodynamic stability and is cost effective. We have been proposed a new type of suspension bridge using a 2-box and 1-box combined girder to apply to such a project And this time, we propose the cable stayed suspension bridge using a 2- box and 1-box combined girder aiming for improvement of aerodynamic stability with increase of torsional rigidity. This paper describes the performance of this cable stayed suspension bridge obtained from aerodynamic analysis. As a result, it can be confirmed that this newly developed cable stayed suspension system has fine characteristics and shows more potential for economical construction than the early proposed suspension system. (author)

  2. Damage detection based on mode shapes of a girder bridge constructed from responses of a moving vehicle under impact excitation

    Science.gov (United States)

    Qi, Zhongqiang; Au, Francis T. K.

    2016-04-01

    The vibration mode shapes are often used to identify damage of bridges because the mode shapes are not only important modal properties but also sensitive to damage. However, the key issue is how to conveniently obtain the mode shapes of a bridge in service. Traditional methods invariably require installation of instruments on the bridge for collection of dynamic responses for constructing mode shapes, which are both costly and inconvenient. Therefore a method is developed to construct the mode shapes of simply supported bridges based on Hilbert Transform using only vehicle acceleration response for identification of the location of damage. Firstly, an algorithm is devised to construct the mode shapes by using the dynamic responses extracted from a moving vehicle under impact excitation. Then, based on these intermediate results, the coordinate modal assurance criterion in conjunction with suitable wavelets is used to identify the location of damage. Compared with the traditional methods, the proposed method uses only the information from the moving vehicle. Moreover, additional impact excitation on the vehicle helps to excite the bridge. This helps to improve the accuracy by overcoming the adverse effects of measurement noise and road surface roughness, which leads to high accuracy of damage detection. To verify the feasibility of the proposed method, some numerical studies have been carried out to investigate the effects of measurement noise, road surface roughness and multiple locations of damage on the accuracy of results.

  3. Finite element analysis of deep wide-flanged pre-stressed girders to understand and control end cracking.

    Science.gov (United States)

    2011-06-01

    Hundreds of prestressed concrete girders are used each year for building bridges in Wisconsin. : The prestress transfer from the prestressing strands to concrete takes place at the girder ends. : Characteristic cracks form in this end region during o...

  4. Forensic testing of a double tee bridge.

    Science.gov (United States)

    2014-12-01

    This report describes an investigation to quantify the behavior of precast, prestressed concrete double-tee bridge : girders made with lightweight concrete. As part of the investigation, three bridge girders were salvaged from a : decommissioned brid...

  5. Field instrumentation and measured response of the I-295 cable-stayed bridge.

    Science.gov (United States)

    1992-01-01

    This first report describes the results of a field study of the live load responses of a segmentally constructed prestressed concrete cable-stayed bridge. The main span of the test structure consists of twin box girders connected by delta frames. Kno...

  6. Development and evaluation of a dual purpose bridge health monitoring and weigh-in-motion system for a steel girder bridge : phase two.

    Science.gov (United States)

    2016-06-30

    The primary objective of this second phase is the further development, demonstration : and field evaluation of a permanent dual purpose bridge weigh-in-motion and health monitoring : system over an extended period of time. Calibrated test truck resul...

  7. Evaluation of continuity detail for precast prestressed girders.

    Science.gov (United States)

    2011-08-01

    The construction of highway bridges using precast prestressed concrete (PSC) girders is considered one of the most : economical construction alternatives because of the advantages they offer (e.g. reducing formwork and rapid construction). : Construc...

  8. Evaluation of continuity detail for precast prestressed girders : tech summary.

    Science.gov (United States)

    2011-08-01

    Building multi-simple span bridges using precast prestressed concrete girders is an easy construction. However, the existence of : expansion joints often leads to a host of problems in their vicinity due to drainage leaks. Furthermore, debris accumul...

  9. Forensic testing of prestress concrete girders after forty years of service.

    Science.gov (United States)

    2013-09-01

    This report describes an investigation to quantify the behavior of precast, prestressed concrete : bridge girders made with high-strength concrete. As part of the investigation, four bridge : girders that were made with 77.2 MPs (11.2 ksi) concrete w...

  10. Practical assessment of magnetic methods for corrosion detection in an adjacent precast, prestressed concrete box-beam bridge

    Science.gov (United States)

    Fernandes, Bertrand; Titus, Michael; Nims, Douglas Karl; Ghorbanpoor, Al; Devabhaktuni, Vijay Kumar

    2013-06-01

    Magnetic methods are progressing in the detection of corrosion in prestressing strands in adjacent precast, prestressed concrete box-beam bridges. This study is the first field trial of magnetic strand defect detection systems on an adjacent box-beam bridge. A bridge in Fayette County, Ohio, which was scheduled for demolition, was inspected. Damage to prestressed box-beams is often due to corrosion of the prestressing strands. The corroded strands show discontinuities and a reduced cross-sectional area. These changes, due to corrosion, are reflected in the magnetic signatures of the prestressing steel. Corrosion in the prestressing steel was detected using two magnetic methods, namely the 'magnetic flux leakage' (MFL) and the 'induced magnetic field'. The purpose of these tests was to demonstrate the ability of the magnetic methods to detect hidden corrosion in box-beams in the field and tackle the logistic problem of inspecting box-beams from the bottom. The inspections were validated by dissecting the bottom of the box-beams after the inspections. The results showed that the MFL method can detect hidden corrosion and strand breaks. Both magnetic field methods were also able to estimate corrosion by detecting the effective cross-sectional area of the strand in sections of the beams. Thus, it was shown that the magnetic methods can be used to predict hidden corrosion in prestressing strands of box-beams.

  11. Experiments with Externally Prestressed Continuous Composite Girders

    Directory of Open Access Journals (Sweden)

    M. Safan

    2001-01-01

    Full Text Available Steel-concrete composite girders have attractive potentials when applied in bridge construction. The serviceability performance of continuous composite girders is becoming more and more a deterministic parameter in the design of this type of structures. An effective method for improving this performance is to apply prestressing to control or completely eliminate concrete deck cracking caused by static and time dependent actions. Little literature has been found addressing the experimental analysis of continuous girders prestressed by means of external deviated tendons. The current research aims to investigate the behavior of a double-span steel composite beam externally prestressed by means of continuous tendons in terms of cracking characteristics, load deflection response, and load carrying capacity. The efficiency of prestressing is evaluated by comparing the results to those of a non-prestressed beam with similar cross sections and spans.

  12. Influence of structural parameters on dynamic characteristics and wind-induced buffeting responses of a super-long-span cable-stayed bridge

    Science.gov (United States)

    Wang, Hao; Chen, Chunchao; Xing, Chenxi; Li, Aiqun

    2014-09-01

    A 3D finite element (FE) model for the Sutong cable-stayed bridge (SCB) is established based on ANSYS. The dynamic characteristics of the bridge are analyzed using a subspace iteration method. Based on recorded wind data, the measured spectra expression is presented using the nonlinear least-squares regression method. Turbulent winds at the bridge site are simulated based on the spectral representation method and the FFT technique. The influence of some key structural parameters and measures on the dynamic characteristics of the bridge are investigated. These parameters include dead load intensity, as well as vertical, lateral and torsional stiffness of the steel box girder. In addition, the influence of elastic stiffness of the connection device employed between the towers and the girder on the vibration mode of the steel box girder is investigated. The analysis shows that all of the vertical, lateral and torsional buffeting displacement responses reduce gradually as the dead load intensity increases. The dynamic characteristics and the structural buffeting displacement response of the SCB are only slightly affected by the vertical and torsional stiffness of the steel box girder, and the lateral and torsional buffeting displacement responses reduce gradually as the lateral stiffness increases. These results provide a reference for dynamic analysis and design of super-long-span cable-stayed bridges.

  13. Higher weight concrete is utilized for the cable stayed bridge construction. In the heavy concrete the counter weight / bridge in Fuchu-Yotsuya; Shachokyo seko ni kojuryo konkurito wo katsuyo. Kaunta ueito wo juryo konkurito de/fuchuyotsuyabashi

    Energy Technology Data Exchange (ETDEWEB)

    Kosugi, Usutaka; Kano, Isamu [NKK Corp., Tokyo (Japan); Miyazaki, Toyoaki

    1998-07-10

    The Fuchu Yotuya Bridge is 446.0 m length of bridge, and it is inverse-trapezoid 3-room box Girder Bridge of all 28.2 m width and 2.5 m grinder height. It is located for the abutment approach so that middle bridge pier may not alienate the running water of the river, and it becomes that it drops below the span in which the side span is short with 91.5 m for 260 m center span. Considerably large negative reaction would be generated in this reason in the edge supporting point (on the abutment), and counter weight of heavy concrete was installed in the box girder of edge supporting point in order to hold this. (NEDO)

  14. Behaviour of parallel girders stabilised with U-frames

    DEFF Research Database (Denmark)

    Virdi, Kuldeep; Azzi, Walid

    2010-01-01

    Lateral torsional buckling is a key factor in the design of steel girders. Stability can be enhanced by cross-bracing, reducing the effective length and thus increasing the ultimate capacity. U-frames are an option often used to brace the girders when designing through type of bridges and where...... overhead bracing is not practical. This paper investigates the effect of the U-frame spacing on the stability of the parallel girders. Eigenvalue buckling analysis was undertaken with four different spacings of the U-frames. Results were extracted from finite element analysis, interpreted and conclusions...

  15. Girder Alignment Plan

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, Zackary; Ruland, Robert; LeCocq, Catherine; Lundahl, Eric; Levashov, Yurii; Reese, Ed; Rago, Carl; Poling, Ben; Schafer, Donald; Nuhn, Heinz-Dieter; Wienands, Uli; /SLAC

    2010-11-18

    The girders for the LCLS undulator system contain components which must be aligned with high accuracy relative to each other. The alignment is one of the last steps before the girders go into the tunnel, so the alignment must be done efficiently, on a tight schedule. This note documents the alignment plan which includes efficiency and high accuracy. The motivation for girder alignment involves the following considerations. Using beam based alignment, the girder position will be adjusted until the beam goes through the center of the quadrupole and beam finder wire. For the machine to work properly, the undulator axis must be on this line and the center of the undulator beam pipe must be on this line. The physics reasons for the undulator axis and undulator beam pipe axis to be centered on the beam are different, but the alignment tolerance for both are similar. In addition, the beam position monitor must be centered on the beam to preserve its calibration. Thus, the undulator, undulator beam pipe, quadrupole, beam finder wire, and beam position monitor axes must all be aligned to a common line. All relative alignments are equally important, not just, for example, between quadrupole and undulator. We begin by making the common axis the nominal beam axis in the girder coordinate system. All components will be initially aligned to this axis. A more accurate alignment will then position the components relative to each other, without incorporating the girder itself.

  16. 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...

  17. Construction of Daiichi Tamagawa bridge; Daiichi Tamagawa kyoryo no seko

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, O.; Tsuyoshi, T. [East Japan Railway Company, Tokyo (Japan); Ota, T.; Sato, S. [Tekken Corp., Tokyo (Japan)

    1997-05-30

    This paper describes the construction of Daiichi Tamagawa Bridge for JR Tazawako Line, which was reconstructed with the Akita Shinkansen Project apart from the existing line. This bridge is a three-span continuous PC cable stayed bridge. To avoid operation accidents due to snow and ice, independent two-column type with a height of 11 m without beam was employed for the main tower. For the construction of upper part, overhang election construction method was adopted, which can be applied all the year round. The main girder has a single box cross section, and a width of 5.5 m and a beam height of 2.3 m. This was also constructed by the overhang construction method. To reduce the construction period, the main tower was constructed by the precast block construction method. The whole bridge was divided into six blocks by considering the hoist performance of cranes. Reinforcement against bearing pressure and cleavage due to the cable tensile force was conducted by adopting saddle structure for the main tower. Oblique members were jointed with the main girder using lateral beams projected from lateral side of girder. Totally seven PC cables were used for each oblique member. Measurements and management during the overhang construction were also described. The construction was over without problems in August, 1996. This bridge is under test operation using test run vehicles. 2 refs., 20 figs., 7 tabs.

  18. Simulation Study on Train-Induced Vibration Control of a Long-Span Steel Truss Girder Bridge by Tuned Mass Dampers

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available Train-induced vibration of steel truss bridges is one of the key issues in bridge engineering. This paper talks about the application of tuned mass damper (TMD on the vibration control of a steel truss bridge subjected to dynamic train loads. The Nanjing Yangtze River Bridge (NYRB is taken as the research object and a recorded typical train load is included in this study. With dynamic finite element (FE method, the real-time dynamic responses of NYRB are analyzed based on a simplified train-bridge time-varying system. Thereinto, two cases including single train moving at one side and two trains moving oppositely are specifically investigated. According to the dynamic characteristics and dynamic responses of NYRB, the fourth vertical bending mode is selected as the control target and the parameter sensitivity analysis on vibration control efficiency with TMD is conducted. Using the first-order optimization method, the optimal parameters of TMD are then acquired with the control efficiency of TMD, the static displacement of Midspan, expenditure of TMDs, and manufacture difficulty of the damper considered. Results obtained in this study can provide references for the vibration control of steel truss bridges.

  19. DISTORTION ANALYSIS OF TILL -WALLED BOX GIRDERS

    African Journals Online (AJOL)

    NIJOTECH

    ASME Journal of Applied. Mechanics. Vol. 54, pp. 165-173. [11] Elsgots, L.E Differential Equations and the Calculus of Variations, Mir. Publishers, Moscow, 1980. [12] Timoshenko, S.P. On the Correction for Shear in the Differential. Equations for Transverse Vibrations of Prismatic Bars. Phil. Mag. Vol. 41, 1921, pp. 744-746.

  20. A multiscale finite element model validation method of composite cable-stayed bridge based on Probability Box theory

    Science.gov (United States)

    Zhong, Rumian; Zong, Zhouhong; Niu, Jie; Liu, Qiqi; Zheng, Peijuan

    2016-05-01

    Modeling and simulation are routinely implemented to predict the behavior of complex structures. These tools powerfully unite theoretical foundations, numerical models and experimental data which include associated uncertainties and errors. A new methodology for multi-scale finite element (FE) model validation is proposed in this paper. The method is based on two-step updating method, a novel approach to obtain coupling parameters in the gluing sub-regions of a multi-scale FE model, and upon Probability Box (P-box) theory that can provide a lower and upper bound for the purpose of quantifying and transmitting the uncertainty of structural parameters. The structural health monitoring data of Guanhe Bridge, a composite cable-stayed bridge with large span, and Monte Carlo simulation were used to verify the proposed method. The results show satisfactory accuracy, as the overlap ratio index of each modal frequency is over 89% without the average absolute value of relative errors, and the CDF of normal distribution has a good coincidence with measured frequencies of Guanhe Bridge. The validated multiscale FE model may be further used in structural damage prognosis and safety prognosis.

  1. Evaluating the performance of skewed prestressed concrete bridge after strengthening

    Science.gov (United States)

    Naser, Ali; Zonglin, Wang

    2013-06-01

    The objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.

  2. Disassembly of an arch bridge deformed due to landslide activity and the replacement of a new bridge in the same site. Jisuberi ni yori henkei shita arch bashi no kaitai to shinbashi no kakekae

    Energy Technology Data Exchange (ETDEWEB)

    Sano, S.; Morimoto, C.; Tomoda, T.; Mizukawa, Y.; Onushi, M.; Ito, T. (Kawasaki Heavy Industries, Ltd., Tokyo (Japan))

    1991-10-20

    This report describes the replacement process of an arch bridge deformed due to landslide activity, selection and contents of the disassembly method, and configuration of the new bridge and its design method. The Ryugu Bridge had been damaged by landslides over an extended period. It was a deck arch bridge having originally a span of 74 meters, but it had shortened by 424 mm due to landslide activity during 14 years since its completion. Then it was decided to be replaced by a new bridge having an adjustable structure to support the movement of its abutments. As disassembly of the deformed arch bridge could be dangerous, the best methodology was studied, and the disassembly was carried out by the cable method. The new bridge had box-girder parts in both side of the main truss, so as to be adjustable to the change of the span length, and the bridge was designed for a working life of 50 years if the bearing supports and expansion joints were reset every 10 years. Concerning the connecting parts between the box-girder and the main truss, appropriateness of the sectional configuration was verified by FEM analysis. 9 refs., 18 figs., 2 tab.

  3. Determination of brace forces caused by construction loads and wind loads during bridge construction : [summary].

    Science.gov (United States)

    2014-04-01

    Bridges are constructed in stages as pilings, : columns, girders, decks, and other components : are added. At each stage, the structure must be : stable. Girders, which add significant weight to : the developing structure, rest on elastomeric : beari...

  4. Comprehensive evaluation of fracture critical bridges.

    Science.gov (United States)

    2014-02-01

    Two-girder steel bridges are classified as fracture critical bridges based on the definition given in the AASHTO LRFD Bridge Design Specifications. In a fracture critical bridge a failure of a tension member leads to collapse of the bridge. However, ...

  5. Field Tests and Simulation of Lion-Head River Bridge

    Directory of Open Access Journals (Sweden)

    Yao-Min Fang

    2007-01-01

    Full Text Available Lion-Head River Bridge is a twin bridge in parallel position. The east-bounded was designed and constructed as a traditional prestress concrete box girder bridge with pot bearings; and the west-bounded was installed with seismic isolation devices of lead rubber bearings. The behavior of the isolated bridge is compared with that of the traditional bridge through several field tests including the ambient vibration test, the force vibration test induced by shakers, the free vibration test induced by a push and fast release system, and the truck test. The bridges suffered from various extents of damage due to the Chi-Chi and the Chi-I earthquakes of great strength during the construction and had been retrofitted. The damage was reflected by the change of the bridges' natural frequencies obtained from the ambient vibration tests. The models of the two bridges are simulated by the finite element method based on the original design drawings. Soil-structure interaction was also scrutinized in this study. The simulation was then modified based on the results from the field tests. Dynamic parameters of bridges are identified and compared with those from theoretical simulation. The efficiency is also verified to be better for an isolated bridge.

  6. Wind Turbine Blade with Angled Girders

    DEFF Research Database (Denmark)

    2011-01-01

    The present invention relates to a reinforced blade for a wind turbine, particularly to a blade having a new arrangement of two or more girders in the blade, wherein each of the girders is connected to the upper part and the lower part of the shell and forms an angle with another girder thereby...... strengthening the shell against transverse shear distortion....

  7. Instrumentation and monitoring of segmental post-tensioned girders

    Science.gov (United States)

    Gomez, Roberto; Escobar, J. Alberto; Guerrero, Hector

    2017-09-01

    As a result of the failure of prefabricated segmental girders during their construction, and in order to evaluate the structural safety of the superstructures of three bridges, different activities of instrumentation, monitoring and mathematical modelling were performed. This paper presents the first stage of a study describing the tasks of instrumentation and monitoring of stresses in an isolated precast post-tensioned beam during the process of application of the tension loading, and before being placed in its final position. The main goal of this task was to confirm the transmission and distribution of stresses at segmental joints. Also, ambient vibration tests were carried out in different phases of tensioning, as well as in the final position of the girder. Recorded stories of accelerations are presented and fundamental periods of vibrating of the isolated girder are derived. The results of the measurements will be used for the calibration of mathematical models and simulation of different scenarios of loads and thus assess the structural safety of the different sections of the superstructures of the three bridges in question.

  8. Effect of Partial Shear Interaction in Steel Concrete Composite Girders

    Science.gov (United States)

    Kalibhat, Madhusudan G.; Upadhyay, Akhil

    2017-10-01

    Steel concrete composite (SCC) structural system has been commonly used both in the buildings and in the bridges because of the advantages it associates when compared to its counterparts such as RC and steel structures. A typical SCC girder consists of a concrete element placed over a steel element. The effectiveness of this composite system is characterized by the type of connection that exists between the two connecting elements. More commonly shear stud connectors are used to connect the two elements. If the shear studs are infinitely rigid, then it brings about full composite action, on the contrary there is no composite action if the studs are not used, between the two connecting elements. It has been observed that generally the composite action exists somewhere between the full composite action and the no composite action, and is called the partial composite action or the partial interaction. More often the partial composite action is overlooked during the design of SCC girders, and the girder is designed assuming that there exists full composite action, because of the complexities in the analysis incorporating the partial composite action. This might lead to the serviceability issues in the SCC girders. Keeping this in mind the present work has been carried out to understand the significance of the partial interaction in SCC girders. In the present work, a comparative study has been made between the available analytical model and the numerical model. Numerical modeling is performed by using commercially available tool such as SAP2000. The main objective of this work is to bring out the relative significance of the partial interaction with respect to the full composite action, with the help of parametric study. Here, the parametric study has been carried by considering various design parameters, such as, span length, degree of shear connection, cross section geometry of steel girder and concrete slab. It is observed that there is significant increase in

  9. Design and construction of the Daini-Chikumagawa bridge; Dai ni Chikumagawa kyoryo no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, N.; Takasusuki, K.; Hirasawa, T.; Kanamori, M.

    1996-01-30

    The Daini-Chikumagawa bridge, having spans of 134m {times} 2 which is the largest in Japan as the concrete railroad, is a prestressed concrete (PC) oblique cable-stayed bridge building on the Hokuriku Shinkansen express line which is constructing towards Nagano Olympic (Feb.1998). Regarding adoption of the oblique cable-stayed bridge for the railroad bridge, there are very few examples on a global scale and in Japan besides this bridge there is only one example (Omoto bridge (Iwate pref.), span = 85m). One H type tower (H = 65m from the surface of bridge) is erected at the center of the Chikuma river and then main girders are built at the front and rear of this tower. These main girders, being separated into 5m {times} 24 blocks per one side excepting surroundings of the tower, are fabricated as a three room box type PC block (total width 12.8m; height 3.0m) each on the river beach near the spot. These blocks are jointed from the tower side by the overhanging work using the constructing vehicles and are fixed with oblique materials (cables; two face hanging system) at intervals of 10m. 4 refs., 16 figs., 5 tabs.

  10. Longest cable-stayed bridge TATARA; Longest shachokyo Tatara Ohashi

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, K. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering

    1998-06-15

    The world`s longest cable-stayed bridge Tatara having a central span of 890 m had the both ends closed in August 1997, linking Namakuchi Island and Omishima Island. Final finishing work is continuing for opening of the West Seto Expressway in the spring of 1999. A cable-stayed bridge supports the bridge girders by perpendicular components of tensile force of cables stayed obliquely. On the other hand, there is a concern that the girders may have axial compression force generated due to horizontal components of the force from the cable tensile force, which can cause buckling of the girders. Therefore, in order to suspend the girders efficiently by increasing the perpendicular components of the cable force, and moreover to suppress the axial compression force on the girders, it is more advantageous to make bridge towers high, hence the towers of this bridge are highest among the bridges on the Shimanami Ocean Road. This bridge whose long girders are stayed with 21-stage multi cables presented a problem in designing the buckling in steel girders near the towers due to the horizontal components of the force generated by the bridge. Discussions were given, therefore, by using load withstanding force experiments using a whole bridge model of 1/50 scale, buckling experiments on full-size reinforcing plate models, and load withstanding force analysis using a tower model. A number of other technical discussions were repeated, by which the world`s longest cable-stayed bridge was completed. 9 figs., 1 tab.

  11. Wind tunnel tests of main girder with Π-shaped cross section

    Science.gov (United States)

    Guo, Junfeng; Hong, Chengjing; Zheng, Shixiong; Zhu, Jinbo

    2017-10-01

    The wind-resistant performance of a cable stayed bridge with IT-shaped girder was investigated by means of wind tunnel tests. Aerodynamic coefficients experiments and wind-induced vibration experiments with a sectional model a geometry scale of l to 60 were conducted. The results have shown that this kind of girder has the necessary condition for aerodynamic stability. Soft flutter of the main girder is a coupled two-degree-of-freedom torsional-bending vibration with single frequency. The amplitude of soft flutter follows a normal distribution, and the amplitude range varies with wind speed and angle of attack. The bridge deck auxiliary facilities can not only improve the critical soft flutter velocity, but also reduce the soft flutter amplitude and the amplitude growth rate.

  12. Valuation of the 12 year old Concrete in the Ulkebugt Bridge, Sisimiut, Greenland

    DEFF Research Database (Denmark)

    Gottlieb, Christian; Olsen, Idar; Henningsen, Jesper Frej

    2011-01-01

    The Ulkebugt bridge is a vital connection for the town Sisimiut, as it is the only link between the airport and the town. The bridge is a box girder bridge with one central pillar. Most of the pillar’s concrete surface is exposed to seawater, with a tide variation around 4 meters. In addition...... to the seawater the bridge is exposed to the rough arctic climate. Furthermore, the mean temperature is below 0 °C for two thirds of the year with many freeze-thaw passages in late autumn and early spring, which increases the opportunity for severe frost damages. The focus has been to evaluate the quality...... and condition of the concrete pillar in terms of composition and the extent of the present deterioration mechanisms, best represented by frost damage and chloride ingress. Results show critical chloride content in the concrete will be reached in approximately 10 years at the depth of the reinforcement bars...

  13. The Vibration Based Fatigue Damage Assessment of Steel and Steel Fiber Reinforced Concrete (SFRC Composite Girder

    Directory of Open Access Journals (Sweden)

    Xu Chen

    2015-01-01

    Full Text Available The steel-concrete composite girder has been usually applied in the bridge and building structures, mostly consisting of concrete slab, steel girder, and shear connector. The current fatigue damage assessment for the composite girder is largely based on the strain values and concrete crack features, which is time consuming and not stable. Hence the vibration-based fatigue damage assessment has been considered in this study. In detail, a steel-steel fiber reinforced concrete (SFRC composite girder was tested. The steel fiber reinforced concrete is usually considered for dealing with the concrete cracks in engineering practice. The composite girder was 3.3m long and 0.45m high. The fatigue load and impact excitation were applied on the specimen sequentially. According to the test results, the concrete crack development and global stiffness degradation during the fatigue test were relatively slow due to the favourable performance of SFRC in tension. But on the other hand, the vibration features varied significantly during the fatigue damage development. Generally, it confirmed the feasibility of executing fatigue damage assessment of composite bridge based on vibration method.

  14. Structural monitoring of Rigolets Pass Bridge.

    Science.gov (United States)

    2009-10-01

    The overall objective of this research project was to evaluate the structural behavior of prestressed highperformance : concrete (HPC) long-span bulb-tee girders utilized in Louisiana bridge construction. To : accomplish this objective, one span of t...

  15. Precast Prestressed Concrete Truss-Girder for Roof Applications

    Directory of Open Access Journals (Sweden)

    Peter Samir

    2014-01-01

    Full Text Available Steel trusses are the most popular system for supporting long-span roofs in commercial buildings, such as warehouses and aircraft hangars. There are several advantages of steel trusses, such as lightweight, ease of handling and erection, and geometric flexibility. However, they have some drawbacks, such as high material and maintenance cost, and low fire resistance. In this paper, a precast concrete truss is proposed as an alternative to steel trusses for spans up to 48 m (160 ft without intermediate supports. The proposed design is easy to produce and has lower construction and maintenance costs than steel trusses. The truss consists of two segments that are formed using standard bridge girder forms with block-outs in the web which result in having diagonals and vertical members and reduces girder weight. The two segments are then connected using a wet joint and post-tensioned longitudinally to form a crowned truss. The proposed design optimizes the truss-girder member locations, cross-sections, and material use. A 9 m (30 ft long truss specimen is constructed using self-consolidated concrete to investigate the constructability and structural capacity of the proposed design. A finite element analysis of the specimen is conducted to investigate stresses at truss diagonals, verticals, and connections. Testing results indicate the production and structural efficiency of the developed system.

  16. Using BIM to Improve the Design and Construction of Bridge Projects: A Case Study of a Long-span Steel-box Arch Bridge Project

    OpenAIRE

    Wenping Liu; Hongling Guo; Heng Li; Yan Li

    2014-01-01

    More and more mega-complex bridge projects are being or will be built worldwide. At the same time, the design and construction of such projects involve more and more challenges, e.g., complex structural designs, complicated construction environments, etc. This research study aims to apply BIM (Building Information Modelling) to bridge projects to improve the efficiency and effectiveness of design and construction. Through the analysis of the characteristics of bridge projects and relevant, as...

  17. Toward an Egyptian Bridge Management System

    Directory of Open Access Journals (Sweden)

    Ahmed M. Saleh

    2013-12-01

    Full Text Available A prototype bridge management system for concrete bridges in Egypt (EBRMS is built and tested. The proposed system has the ability to record different inventory data, has tools for condition rating, priority ranking and cost optimization at both bridge and network levels. Condition rating is based on the type, extent, and severity of defects and urgency of intervention, all based on observations made during the inspections. It also takes into account the importance of the deteriorated elements. Priority ranking is evaluated on the basis of a knowledge-base stored in the system. It is calculated using four parameters: condition rating; remaining service life; safety index; and impact of the structure on the network. The developed framework of EBRMS consists of three main modules: database and inspections, condition rating and decision making modules. Details of each of the system capabilities are based on the published research work, mainly on the BRIME project. Testing and verification of the proposed scheme are carried out using a virtual bridge network and available published data as the knowledge base. Twelve actual bridges of different types (slab and beam, box girder and slab types at different locations and under varying service conditions are assumed in the virtual network. Various scenarios of damage states, imposed policies and budget constraints were assumed for testing and validation. All results were reasonable and within acceptable domain.

  18. Nonlinear seismic analysis of continuous RC bridge

    Directory of Open Access Journals (Sweden)

    Čokić Miloš M.

    2017-01-01

    Full Text Available Nonlinear static analysis, known as a pushover method (NSPA is oftenly used to study the behaviour of a bridge structure under the seismic action. It is shown that the Equivalent Linearization Method - ELM, recommended in FEMA 440, is appropriate for the response analysis of the bridge columns, with different geometric characteristics, quantity and distribution of steel reinforcement. The subject of analysis is a bridge structure with a carriageway plate - a continuous beam with three spans, with the 24 + 40 + 24 m range. Main girder is made of prestressed concrete and it has a box cross section of a constant height. It is important to study the behaviour, not only in the transverse, but also in the longitudinal direction of the bridge axis, when analysing the bridge columns exposed to horizontal seismic actions. The columns were designed according to EN1992, parts 1 and 2. Seismic action analysis is conducted according to EN 1998: 2004 standard. Response spectrum type 1, for the ground type B, was applied and the analysis also includes 20% of traffic load. The analysis includes the values of columns displacement and ductility. To describe the behaviour of elements under the earthquake action in both - longitudinal and transverse direction, pushover curves were formed.

  19. Bridges

    NARCIS (Netherlands)

    Zant, W.

    2017-01-01

    We estimate to what extent bridges in Mozambique lead to transport cost reductions and attribute these reductions to key determinants, in particular road distance, road quality and crossing borders. For identification we exploit the introduction of a road bridge over the Zambezi river, in August

  20. A software prototype for assessing the reliability of a concrete bridge superstructure subjected to chloride-induced reinforcement corrosion

    DEFF Research Database (Denmark)

    Schneider, Ronald; Thöns, Sebastian; Fischer, Johannes

    2014-01-01

    A software prototype is developed for assessing and updating the reliability of single-cell prestressed concrete box girders subjected to chloride-induced reinforcement corrosion. The underlying system model consists of two integrated sub-models: a condition model for predicting the deterioration...... through Bayesian updating on the basis of the DBN model. To demonstrate the effect of partial inspections, the software prototype is applied to a case study of a typical highway bridge with six spans. The case study illustrates that it is possible to infer the condition of uninspected parts...

  1. On the Kinematics of Undulator Girder Motion

    Energy Technology Data Exchange (ETDEWEB)

    Welch, J; /SLAC

    2011-08-18

    The theory of rigid body kinematics is used to derive equations that govern the control and measurement of the position and orientation of undulator girders. The equations form the basis of the girder matlab software on the LCLS control system. The equations are linear for small motion and easily inverted as desired. For reference, some relevant girder geometrical data is also given. Equations 6-8 relate the linear potentiometer readings to the motion of the girder. Equations 9-11 relate the cam shaft angles to the motion of the girder. Both sets are easily inverted to either obtain the girder motion from the angles or readings, or, to find the angles and readings that would give a desired motion. The motion of any point on the girder can be calculated by applying either sets of equations to the two cam-planes and extrapolating in the z coordinate using equation 19. The formulation of the equations is quite general and easily coded via matrix and vector methods. They form the basis of the girder matlab software on the LCLS control system.

  2. Application of differential fiber Bragg grating displacement cell in bridge crack monitoring

    Science.gov (United States)

    Yue, Li-na; Huang, Jun; Jiang, De-sheng; Wang, Jun-jie

    2008-12-01

    During the construction and service period of concrete bridges, the cracks often influence the quality of the project even the safety of the structure. An effective and long-term crack monitoring of concrete bridges with the appropriate choice of displacement sensors is imperative under the situation. The differential fiber bragg grating displacement cell is based on the composite structure which consisted of pulling spring and cantilever. It has realized differential measure of normal FBG displacement sensor and has solved the serious problem of temperature disturbance. The differential fiber bragg grating displacement cell has the advantages of high accuracy, anti-interference, long distance transmitting and good durability etc. In this paper, the differential fiber bragg grating displacement cells were applied to monitor the cracks of web slabs during the tension process of external prestressed tendons when the continuous prestressed concrete box girder bridges and continuous concrete rigid frame bridges were maintained and reinforced. A group of typical cracks of web slabs was selected respectively in the continuous prestressed concrete box girder bridge and the continuous concrete rigid frame bridge. And a group of three sensors were installed across the three cracks. The external prestressed tendons had been tensioned by four grades. Then the widths of these cracks were recorded in accordance with the four tension grades of the external prestressed tendons: before tension, 10% tension, 80% tension, 100% tension. The results of the differential FBG displacement cells used during the process of tension of external prestressed tendons show that the cracks monitoring data are accurate and in accordance with the cracks changing rule.

  3. Assessing the Needs for intermediate diaphragms in prestressed concrete bridges : summary of report.

    Science.gov (United States)

    2008-05-01

    Reinforced concrete Intermediate Diaphragms (IDs) are currently being used in prestressed concrete (PC) girder bridges in Louisiana. Some of the advantages of providing IDs are disputed in the bridge community because the use of IDs increases the cos...

  4. 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

  5. Cross-frame connection details for skewed steel bridges.

    Science.gov (United States)

    2010-10-30

    This report documents a research investigation on connection details and bracing layouts for stability : bracing of steel bridges with skewed supports. Cross-frames and diaphragms play an important role in stabilizing : steel girders, particularly du...

  6. Structural Repair Of Prestressed Concrete Bridge Beams

    OpenAIRE

    Pekyer, Bülent

    2010-01-01

    Each year a lot of prestressed concrete beams are damaged by overwheight vehicles and environmental effects. There are numerous repair techniques proposed by entrepreneurial and academic institutions which restore prestressed concrete girder flexural strength and save both material and economic resources. This document focuses on the practical application of prestressed concrete bridge girder repair methods. In this document, repair methods are presented for three prototype prestressed concre...

  7. The influence of package size and flute type of corrugated boxes on load bridging in unit loads

    Science.gov (United States)

    Jonghun Park; Laszlo Horvath; Marshall S. White; Samantha Phanthanousy; Philip Araman; Robert J. Bush

    2017-01-01

    Shipping pallets often are designed with the assumption that the payload carried is flexible and uniformly distributed on the pallet surface. However, packages on the pallet can act as a series of discrete loads, and the physical interactions among the packages can add stiffness to the pallet/load combination. The term ‘load bridging’ has been used to describe this...

  8. Wind Tunnel Experiments with Active Control of Bridge Section Model

    DEFF Research Database (Denmark)

    Hansen, Henriette I.; Thoft-Christensen, Palle

    This paper describes results of wind tunnel experiments with a bridge section model where movable flaps are integrated in the bridge girder so each flap is the streamlined part of the edge of the girder. This active control flap system is patented by COWIconsult and may be used to increase...... the flutter wind velocity for future ultra-long span suspension bridges. The purpose of the wind tunnel experiments is to investigate the principle to use this active flap control system. The bridge section model used in the experiments is therefore not a model of a specific bridge but it is realistic...

  9. Active Control of Long Bridges Using Flaps

    DEFF Research Database (Denmark)

    Hansen, H. I.; Thoft-Christensen, Palle

    The main problem in designing ultra-long span suspension bridges is flutter. A solution to this problem might be to introduce an active flap control system to increase the flutter wind velocity. The investigated flap control system consists of flaps integrated in the bridge girder so each flap...... is the streamlined part of the edge of the girder. Additional aerodynamic derivatives are shown for the flaps and it is shown how methods already developed can be used to estimate the flutter wind velocity for a bridge section with flaps. As an example, the flutter wind velocity is calculated for different flap...

  10. Pretensioned concrete girder end crack control : research brief.

    Science.gov (United States)

    2017-02-01

    Research Objectives: : Prove through physical testing and observation that debonding strands can reduce or eliminate critical girder end cracking : Eliminate cracking in the bottom flange of the girders, where cracks could allow moisture to r...

  11. Analysis of Biaxially Stressed Bridge Deck Plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, Tommi Højer

    2012-01-01

    The ultimate state analysis of bridge deck plates at the intersection zone between main girders and transverse beams is complicated by biaxial membrane stresses, which may be in compression or tension in either direction depending on the bridge configuration and the specific location. This paper...

  12. Improving the Dynamics of Suspension Bridges using Active Control Systems

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Improving the dynamics of suspension bridge using active control is discussed in this paper. The main dynamic problem with long suspension bridges is the aeroelastic phenomenon called flutter. Flutter oscillations of a bridge girder is a stability problem and the oscillations are perpendicular...

  13. Advanced Bridge Capacity and Structural Integrity Assessment Methodology

    Science.gov (United States)

    2013-03-01

    bridges , including reinforced concrete bridges with continuous girders across a support and prestressed structures. Identifying the class of...assessment of reinforced concrete bridges by making improved estimates of the level of longitudinal and shear reinforcement. The pro- posed assessment...Figure 7. AASHTO HS20-44 Truck (Precast/ Prestressed Concrete Institute 2003). ......................... 11 Figure 8. California Permit Truck (Caltrans

  14. Cable-stayed PC bridge with inclined main tower. Hachinohe port island bridge; Keisha shuto to yusuru 2 keikan renzoku PC shachokyo. Hachinoheko port island renrakykyo (kasho)

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, A. [Hachinohe Institute of Technology, Aomori (Japan)

    1994-09-15

    The design and construction of the inclined main bridge, which is being constructed at the mouth of the Hachinohe Harbor (in Japan), are outlined in this paper. This connecting bridge has an overall length of 265.56 m, and consists of the main bridge member of asymmetric 2 cable-stayed PC bridge and the 3 cable-stayed PC box member bridge. An asymmetric design was employed for the main bridge frame to ensure the access space for small ships passing between bridge girders, easy maintenance and service, improved economy, and excellent view. The main tower is a single-pillar reinforced concrete structure with an inclination of 15{degree} and 47 m in height. Forty-eight diagonal cables are arranged so that 12 cable trains are connected to the main tower on the right and left sides respectively, and the back-stay cable structure is used for each upper 3 cable trains to improve safety against the earthquake. The main beam is made by a prestressed concrete structure with inverse trapezoidal 3-chamber frame section. This structure is superior in increasing the safety against wind. Steel tube sheet-pile well is selected for the bridge pier base, and debris layer is selected as a support layer for the base. For the construction of the lower bridge section, sand conversion through predrilling of rubble-mound and debris layer was executed. The underwater non-separative concrete and embedded type frame are used around the bridge piers and its surrounding. For the construction of the upper bridge section, steel frames are used inside the main tower to ensure the construction precision. 7 figs.

  15. Assessment of Replacement Bridge using Proof Load Test

    Science.gov (United States)

    Sundru, Saibabu

    2017-11-01

    This work begins with an overview of the condition assessment of old bridge and explained reasons for demolishing of the bridge. Briefly presented flexural analysis of two stage post-tensioned prestressed concrete girder, which will be replace the old (new bridge). Construction of I-girder and composite girder at first stage and second stage prestressing respectively is explained with figures. Assessment of the load-caring capacity of the one span of the replacement bridge with simple supports using proof load test is presented which is mandatory according to Indian standards. Weighted sand bags were used to load the bridge up to a predetermined service load with impact factor. Deflections of the I-girders of the bridge were measured at selected locations along and across the bridge span and compared with computed values. Linear response was observed during loading and unloading. Considering the load test results, theoretical estimation and criteria as stipulated in codes of practice, it can be inferred that prestressed concrete I-girder bridge span has adequate capacity to carry the loads and hence, deemed to have passed the test.

  16. Repair of Morganza Spillway Bridge bent pile cap using carbon fiber reinforcement (CFR).

    Science.gov (United States)

    2016-04-01

    The pile cap of an end bent of the Morganza Spillway Bridge suffered extensive damage at the girder bearing locations, : particularly on the side where the pounding of the girders by the adjacent concrete deck located on the approach side of the : be...

  17. Repair of Morganza Spillway Bridge Bent Pile Cap Using Carbon Fiber Reinforcement (CFR) : Research Project Capsule

    Science.gov (United States)

    2012-09-01

    The pile cap of an end bent of the Morganza Spillway Bridge suff ered extensive damage at the girder bearing : locations on one side, due to the pounding of the girders at these locations by the adjacent concrete deck : located on the approach side o...

  18. Repair of Morganza Spillway Bridge bent pile cap using carbon fiber reinforcement (CFR) : tech summary.

    Science.gov (United States)

    2016-04-01

    The pile cap of an end bent of the Morganza Spillway Bridge suffered extensive damage at the girder bearing locations, particularly on the side where the pounding of the girders by the adjacent concrete deck located on the approach side of the bent. ...

  19. Multiobjective optimization of planar truss girder

    Directory of Open Access Journals (Sweden)

    Timár Imre

    2017-01-01

    Full Text Available The continuous increasing trends in the case of the raw material-, energy-, production-, and operation costs have been made necessary, the development of the numerical methods made it possible to spread widely the optimal design methods in the technical practice.The method of optimal design with multiobjective functions is useful when the designer has to rank the different construction variations. We apply this method to optimal design of truss girder when the aim functions are the mass of girder and the deflection of the structure. We change the cross-section of beam of girder as unknown parameter. The restrictions are concerning the design resistance of tensile bars and the stability of compressed bars.

  20. Construction of cable-stayed prestressed concrete bridge, having Japan`s first independent single slanted tower; Nippon hatsu no keisha shuto wo motsu PC shachokyo no seko

    Energy Technology Data Exchange (ETDEWEB)

    Sanada, Y.; Naito, H. [Penta-Ocean Construction Co. Ltd., Tokyo (Japan); Takeuchi, H.; Mikami, T.

    1994-08-01

    In the Hachinoe Harbor, Aomori prefecture, a man-made island (Hachinoe Port Island) is being constructed by reclamation. When proceeding this undertaking plan, a construction of the Hachinoe Harbor Port Island connection bridge, which connects the man-made island with the existing harbor district, was made an urgent necessity. This connecting bridge is a bridge with a total length of 256.56m, and is constituted of two span continuous PC slanted bridge and three span continuous PC box girder bridge. This slanted bridge has become an asymmetrical structure due to several conditions coming from a plan, and moreover it has the first structural shape as a road bridge in Japan, of which main tower is 15{degree} slanted independent single tower type, there are more problems for the work execution compared with other normal slanted bridges. In addition, because it is situated in an extremely cruel environment like in the cold region and in the marine environment, a sufficient consideration is required for its design and work execution in order to insure a durability. In this report, an outline of work execution content about PC slanted bridge part currently under a construction zealously aiming at a completion in the end of the fiscal year 1994 is introduced. 2 refs., 14 figs., 4 tabs.

  1. Design and construction of Ogawa bridge; Ogawa bashi no sekkei to seko

    Energy Technology Data Exchange (ETDEWEB)

    Hori, T.; Chigira, F. [Kajima Corp., Tokyo (Japan); Sakao, H.

    1995-09-30

    Ogawa bridge 230m long by 15.5m wide has been planned on the national road No.401 at Katashina-mura in Gunma Prefecture. Structure mode is two spans continuous PC cable-stayed obliquely system, and a main tower is H type (height: 56m from the road surface) and is located at the center of the bridge alone. This place corresponding to the entrance of Oze famous national park, the main tower is designed so as to have bulge, imaging Mizubasho (lysichiton camtschatcense), from the middle part of the pier to the lower part of the main tower. Arrangement of the cables is designed as two faces of hung fun type and one side face is composed of 13 steel strands (dia. 15.2mm wire x 27 (partly 19); covered with PE tube) in front and rear respectively. A main girder is the box type PC block 2.3m height by 4m or 3m long, and 3m long one is for fastening with a cable. Centering on the main tower, the girder blocks are successively connected in front and rare alternatively and are fastened with cables in part. This overhanging connection work is carried out by two special movable conveyers `Wagens`. 26 figs., 2 tabs.

  2. Full scale strain monitoring of a suspension bridge using high performance distributed fiber optic sensors

    Science.gov (United States)

    Xu, Jinlong; Dong, Yongkang; Zhang, Zhaohui; Li, Shunlong; He, Shaoyang; Li, Hui

    2016-12-01

    This paper investigated field monitoring of a 1108 m suspension bridge during an assessment load test, using integrated distributed fibre-optic sensors (DFOSs). In addition to the conventional Brillouin time domain analysis system, a high spatial resolution Brillouin system using the differential pulse-width pair (DPP) technique was adopted. Temperature compensation was achieved using a Raman distributed temperature sensing system. This is the first full scale field application of DFOSs using the Brillouin time domain analysis technique in a thousand-meter-scale suspension bridge. Measured strain distributions along the whole length of the bridge were presented. The interaction between the main cables and the steel-box-girder was highlighted. The Brillouin fibre-optic monitoring systems exhibited great facility for the purposes of long distance distributed strain monitoring, with up to 0.05 m spatial resolution, and 0.01 m/point sampling interval. The performance of the Brillouin system using DPP technique was discussed. The measured data was also employed for assessing bridge design and for the assessment of structural condition. The results show that the symmetrical design assumptions were consistent with the actual bridge, and that the strain values along the whole bridge were within the safety range. This trial field study serves as an example, demonstrating the feasibility of highly dense strain and temperature measurement for large scale civil infrastructures using integrated DFOSs.

  3. Wireless Impedance Sensor with PZT-Interface for Prestress-Loss Monitoring in Prestressed Concrete Girder

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Khac Duy; Lee, So Young; Kim, Jeong Tae [Pukyong National University, Busan (Korea, Republic of)

    2011-12-15

    Ensuring the designed prestress force is very important for the safety of prestressed concrete bridge. The loss of prestress force in tendon could significantly reduce load carrying capacity of the structure. In this study, an automated prestress-loss monitoring system for prestressed concrete girder using PZT-interface and wireless impedance sensor node is presented. The following approaches are carried out to achieve the objective. Firstly, wireless impedance sensor nodes are designed for automated impedance-based monitoring technique. The sensor node is mounted on the high-performance Imote2 sensor platform to fulfill high operating speed, low power requirement and large storage memory. Secondly, a smart PZT-interface designed for monitoring prestress force is described. A linear regression model is established to predict prestress-loss. Finally, a system of the PZT-interface interacted with the wireless sensor node is evaluated from a lab-scale tendon-anchorage connection of a prestressed concrete girder.

  4. Evaluation of the need for longitudinal median joints in bridge decks on dual structures.

    Science.gov (United States)

    2015-09-01

    The primary objective of this project was to determine the effect of bridge width on deck cracking in bridges. Other parameters, : such as bridge skew, girder spacing and type, abutment type, pier type, and number of bridge spans, were also studied. ...

  5. TSUNAMI WAVE LOADING ON A BRIDGE DECK WITH PERFORATIONS

    Directory of Open Access Journals (Sweden)

    P. Lukkunaprasit

    2011-01-01

    Full Text Available Tsunamis have damaged bridges to various extents in the 2004 Indian Ocean Tsunami. This paper reports an experimental investigation of the effect of perforations in the girders and parapets on the horizontal tsunami loads. The results reveal that the maximum pressures impinging on the front face of the pier and deck are 4.5 and 3 times the hydrostatic pressure at 80mm nominal wave heights. The percentage of force reduction of the bridge deck with 10% perforated girders and 60% perforated parapets is found to be close to the percentage of perforation area in the deck. However, it is also noted that perforations in the bridge deck can substantially reduce the tsunami forces acting on it throughout the force time history. Thus, less damage to the bridge is anticipated for the bridge deck with perforations in girders and parapets.

  6. Construction of the Maizuru first bridge (the Ohara bridge); Maizuru ichigosen (Oharakyo) no seko

    Energy Technology Data Exchange (ETDEWEB)

    Otsuki, Y. [Kyoto Prefectural Government Office, Kyoto (Japan); Hirose, T.; Tateyama, A. [Fujita Corp., Tokyo (Japan); Kawano, S. [Sumitomo Construction Co. Ltd., Tokyo (Japan)

    1997-05-30

    This paper describes construction of the Maizuru First Bridge of the Kyoto Traverse Highway. This bridge construction includes the PC three-span continuous rahmen bridge, girders of PC three-span continuous knee brace rahmen bridge, tunnel, and earthworks. The structure in the valley was selected by considering the straight line on plane figure, distance of 50 m under beams, steep terrain, and compaction of carry-in unit of construction materials. The carry-in route was kept by the earlier earthworks for the main road and construction of the tunnel section. Incline facilities generally used for dam constructions were used on the steep slope. For the construction of knee brace piers, temporary column members previously fabricated separately in the factory were constructed at the site, and reinforced concrete placing from the joint of bridge piers was conducted. For the construction of main girders, overhang erection construction method was employed using temporary column members. The PC steel twisted cables were used for the vertical tightening, and the PC steel rods were used for the lateral tightening. After the overhang erection construction of main girders, a jack was placed at the center joint. The reaction forces of temporary columns and auxiliary columns were released by expanding bridge body in the bridge axis direction using horizontal force. Thus, the bending moment generated at the basement of girders was improved. 1 ref., 20 figs., 5 tabs.

  7. Bridges Dynamic Parameters Identification Based On Experimental and Numerical Method Comparison in Regard with Traffic Seismicity

    Science.gov (United States)

    Krkošková, Katarína; Papán, Daniel; Papánová, Zuzana

    2017-10-01

    The technical seismicity negatively affects the environment, buildings and structures. Technical seismicity means seismic shakes caused by force impulse, random process and unnatural origin. The vibration influence on buildings is evaluated in the Eurocode 8 in Slovak Republic, however, the Slovak Technical Standard STN 73 0036 includes solution of the technical seismicity. This standard also classes bridges into the group of structures that are significant in light of the technical seismicity – the group “U”. Using the case studies analysis by FEM simulation and comparison is necessary because of brief norm evaluation of this issue. In this article, determinate dynamic parameters by experimental measuring and numerical method on two real bridges are compared. First bridge, (D201 – 00) is Scaffold Bridge on the road I/11 leading to the city of Čadca and is situated in the city of Žilina. It is eleven – span concrete road bridge. The railway is the obstacle, which this bridge spans. Second bridge (M5973 Brodno) is situated in the part of Žilina City on the road of I/11. It is concrete three – span road bridge built as box girder. The computing part includes 3D computational models of the bridges. First bridge (D201 – 00) was modelled in the software of IDA Nexis as the slab – wall model. The model outputs are natural frequencies and natural vibration modes. Second bridge (M5973 Brodno) was modelled in the software of VisualFEA. The technical seismicity corresponds with the force impulse, which was put into this model. The model outputs are vibration displacements, velocities and accelerations. The aim of the experiments was measuring of the vibration acceleration time record of bridges, and there was need to systematic placement of accelerometers. The vibration acceleration time record is important during the under – bridge train crossing, about the first bridge (D201 – 00) and the vibration acceleration time domain is important during

  8. Steel framing strategies for highly skewed bridges to reduce/eliminate distortion near skewed supports.

    Science.gov (United States)

    2014-05-01

    Different problems in straight skewed steel I-girder bridges are often associated with the methods used for detailing the cross-frames. Use of theoretical terms to describe these detailing methods and absence of complete and simplified design approac...

  9. Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

    Directory of Open Access Journals (Sweden)

    Ali Fadhil Naser

    2016-12-01

    Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

  10. Effect of Piers Shape on the Dynamic Structural Responses of Prestressed Concrete Bridge: Part II

    Directory of Open Access Journals (Sweden)

    Ali Fadhil Naser

    2016-03-01

    Full Text Available Pier of bridge is usually used as a general term for any type of substructure located between horizontal spans and foundations. Piers give vertical supports for spans at intermediate points and perform two main functions. The objective of this study is to inspect the effect of piers shape on the dynamic structural performance by adopting theoretical dynamic analysis. The results of dynamic analysis of 25 bridges models show that the maximum value of natural frequency is equal to 5.64Hz in two circles piers bridge model. Therefore, this type of model has good stiffness and bearing capacity. The two square piers model, the one circle pier model, and the two circles piers model appear good stiffness because of the natural frequencies (5.30Hz, 5.52Hz, and 5.64Hz are more than the maximum forced frequencies (4.52Hz, 5.45Hz, and 4.52Hz respectively. According to the comparison between all models results, the two circles piers model has the higher stiffness because of this model has the maximum value of natural frequency (5.64Hz and it is more than all forced vibration frequencies of all others models. Therefore, this study recommends that using the bridge model of two circles piers in the bridges construction that consists of three spans (30m+40m+30m with section of box girder.

  11. A Comparative Assessment of Aerodynamic Models for Buffeting and Flutter of Long-Span Bridges

    Directory of Open Access Journals (Sweden)

    Igor Kavrakov

    2017-12-01

    Full Text Available Wind-induced vibrations commonly represent the leading criterion in the design of long-span bridges. The aerodynamic forces in bridge aerodynamics are mainly based on the quasi-steady and linear unsteady theory. This paper aims to investigate different formulations of self-excited and buffeting forces in the time domain by comparing the dynamic response of a multi-span cable-stayed bridge during the critical erection condition. The bridge is selected to represent a typical reference object with a bluff concrete box girder for large river crossings. The models are viewed from a perspective of model complexity, comparing the influence of the aerodynamic properties implied in the aerodynamic models, such as aerodynamic damping and stiffness, fluid memory in the buffeting and self-excited forces, aerodynamic nonlinearity, and aerodynamic coupling on the bridge response. The selected models are studied for a wind-speed range that is typical for the construction stage for two levels of turbulence intensity. Furthermore, a simplified method for the computation of buffeting forces including the aerodynamic admittance is presented, in which rational approximation is avoided. The critical flutter velocities are also compared for the selected models under laminar flow.

  12. Effects of CFRP Strengthening on Dynamic and Fatigue Responses of Composite Bridge

    Directory of Open Access Journals (Sweden)

    Kittisak Kuntiyawichai

    2014-01-01

    Full Text Available This paper investigates the effect of CFRP strengthening on dynamic and fatigue responses of composite bridge using finite element program ABAQUS. Dynamic and fatigue responses of composite bridge due to truck load based on AASHTO standard are investigated. Two types of CFRP strengthening techniques, CFRP sheets and CFRP deck, are applied to both the damaged and undamaged bridges. For the case of damaged bridge, two through-thickness crack sizes, 3 mm and 6 mm in depth, are assumed at midspan of the steel girders. Furthermore, effects of the number of steel girders on the dynamic and fatigue responses are also considered. The results show that the maximum responses of composite bridges occur for dual lane cases. By using CFRP as a strengthening material, the maximum stress and deflection of the steel girders reduce and consequently increase the fatigue life of the girders. After introducing initial crack into the steel girders of the composite bridges, the fatigue life of the bridges is dramatically reduced. However, the overall performance of the damaged composite bridge can be improved by using CFRP, albeit with less effectiveness. Therefore, if cracks are found, steel welding must be performed before strengthening the composite bridge by CFRP.

  13. Estimating Design Resistance of Wrought Balcony Girders

    Directory of Open Access Journals (Sweden)

    Jung Karel

    2017-06-01

    Full Text Available The contribution is focused on reliability of balcony girders of a Czech national heritage monument. As preliminary reliability assessment suggests insufficient resistance, a series of nondestructive tests supplemented by a single tensile test are performed and evaluated by the statistical methods. Values of material properties, recommended in standards for historic materials, seem to be overly conservative and it is advised to specify properties of historic metallic materials by tests.

  14. Erection of the Meiko-Central bridge; Meiko chuo ohashi no kasetsu

    Energy Technology Data Exchange (ETDEWEB)

    Kaneda, S.; Nishikawa, K.; Nagai, Y.; Ishihara, S.; Tsunekawa, M.; Yoshino, S. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

    1997-10-20

    This is a 1170m-long triple-span continuous steel cable-stayed bridge with the central span measuring 590m, built to traverse Nagoya Port as part of the Isewangan highway. The 190m-high main towers are A-shaped, and have an octagonal cross section to stay stable against winds. The joints were designed to be welded mainly on the spot so as not to affect the surrounding landscape, and in this welding process the achievement of prescribed accuracy was the important technological task. The main girder was a 37m-wide multi-chamber/single-box type, and the steel stabs were installed by on-site welding. Since the erection was carried out above the ship course, a method was used in which the main girder was hung over with the cable stretched long, which demanded constant prudence to assure accuracy throughout the work. The cable is a 17-stage 2-face multi-fan type, a semi-parallel wire strand coated with polyethylene and white fluoroethylene resin. As for accuracy management for erection, it was accomplished by adjusting the amount of shim introduced into each of the four cables every time one stage of cable was erected for the side span and central span. Every accuracy management requirement met the target value with an adequate margin. 6 refs., 10 figs., 4 tabs.

  15. Application of ultra-high performance concrete to bridge girders.

    Science.gov (United States)

    2009-02-01

    "Ultra-High Performance Concrete (UHPC) is a new class of concrete that has superior performance characteristics : compared to conventional concrete. The enhanced strength and durability properties of UHPC are mainly due to optimized : particle grada...

  16. Checking the low track lattice girder bridges for robustness

    Directory of Open Access Journals (Sweden)

    Bucur Carmen

    2016-07-01

    Full Text Available When you say about a thing or a being that they are robust, you imagine a complete entity from the point of view of its component parts giving out force and safety. The notion of robustness is associated with a lot of activity domains. Consequently, there are many definitions individualizing the robustness notion depending on the study domain.

  17. Self-compacting concrete for prestressed bridge girders

    Science.gov (United States)

    Erkmen, Bulent

    The purpose of this study was to examine social mobility as a motivation for first-generation college students in reaching attainment at two-year technical colleges. The research question was to what degree has the perception of social mobility influenced first generation college students at technical colleges to complete their career educational goals. Graduates of a two-year technical college were asked a series of open-ended questions regarding their past experiences and perceptions of attending and completing a two-year technical college program; their childhood perceptions of their social status; and experiences with family members regarding their change in social class status. These questions were designed to determine their feelings, viewpoints, reflections, experiences, struggles, and thoughts about attainment (completing their post-secondary education) and the extent to which social mobility influenced their decision to complete their education. The benefits of this research include an understanding of social mobility and educational attainment. Results of this study could be used to better understand the process that first generation college students go through in order to attain their educational goals. The information from this study may be useful for technical college administrations to help design programs and processes for future first-generation college students' success and aid in retention of these students.

  18. Embedded Electromechanical Impedance and Strain Sensors for Health Monitoring of a Concrete Bridge

    Directory of Open Access Journals (Sweden)

    Dansheng Wang

    2015-01-01

    Full Text Available Piezoelectric lead zirconate titanate (PZT is one of the piezoelectric smart materials, which has direct and converse piezoelectric effects and can serve as an active electromechanical impedance (EMI sensor. The design and fabrication processes of EMI sensors embedded into concrete structures are presented briefly. Subsequently, finite element modeling and modal analysis of a continuous rigid frame bridge are implemented by using ANSYS and MIDAS and validated by the field test results. Uppermost, a health monitoring technique by employing the embedded EMI and strain sensors is proposed in this paper. The technique is not based on any physical model and is sensitive to incipient structural changes for its high frequency characteristics. A practical study on health monitoring of the continuous rigid frame bridge is implemented based on the EMI and strain signatures. In this study, some EMI and strain sensors are embedded into the box-sectional girders. The electrical admittances of distributed EMI active sensors and the strains of concrete are measured when the bridge is under construction or in operation. Based on the electrical admittance and strain measurements, the health statuses of the continuous rigid frame bridge are monitored and evaluated successfully in the construction and operation stages using a root-mean-square deviation (RMSD index.

  19. Hybrid networking sensing system for structural health monitoring of a concrete cable-stayed bridge

    Science.gov (United States)

    Torbol, Marco; Kim, Sehwan; Chien, Ting-Chou; Shinozuka, Masanobu

    2013-04-01

    The purpose of this study is the remote structural health monitoring to identify the torsional natural frequencies and mode shapes of a concrete cable-stayed bridge using a hybrid networking sensing system. The system consists of one data aggregation unit, which is daisy-chained to one or more sensing nodes. A wireless interface is used between the data aggregation units, whereas a wired interface is used between a data aggregation unit and the sensing nodes. Each sensing node is equipped with high-precision MEMS accelerometers with adjustable sampling frequency from 0.2 Hz to 1.2 kHz. The entire system was installed inside the reinforced concrete box-girder deck of Hwamyung Bridge, which is a cable stayed bridge in Busan, South Korea, to protect the system from the harsh environmental conditions. This deployment makes wireless communication a challenge due to the signal losses and the high levels of attenuation. To address these issues, the concept of hybrid networking system is introduced with the efficient local power distribution technique. The theoretical communication range of Wi-Fi is 100m. However, inside the concrete girder, the peer to peer wireless communication cannot exceed about 20m. The distance is further reduced by the line of sight between the antennas. However, the wired daisy-chained connection between sensing nodes is useful because the data aggregation unit can be placed in the optimal location for transmission. To overcome the limitation of the wireless communication range, we adopt a high-gain antenna that extends the wireless communication distance to 50m. Additional help is given by the multi-hopping data communication protocol. The 4G modem, which allows remote access to the system, is the only component exposed to the external environment.

  20. Ultimate strength analysis of long-span cable-stayed bridges; Chodai chachokyo no shukyoku kyodo kaiseki to kyodo ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X.; Yamaguchi, H. [Saitama Univ., Urawa (Japan)] Nagai, M. [Nagaoka Technical Coll., Niigata (Japan)

    1998-07-21

    Recently, span of cable-stayed bridges has been getting loner and longer, present situation is that cable-stayed bridges with span 600 to 800m class have been built inside and outside the country, and accurate determination of its ultimate strength has been an important problem statistically. However, concrete design method for evaluating load bearing stress of long-span cable-stayed bridge. Particularly of the main beam whose axial stress is dominating, has not been established so far. As for cable-stayed bridge, even for long-span, effect of plasticization of cross section on ultimate strength is severe because there is little effect of geometric nonlinearity and it is thought that accurate evaluation of ultimate strength only by elastic finite potential analysis is difficult. Accordingly, it is necessary to study the behavior by using combined nonlinear analysis considering the nonlinearity of the material in order to evaluate the safety and economy to long-span cable-stayed bridge. In this report, 3 dimensional analysis method was formularized taking into account the combine nonlinearity of multi-box girder and analysis program of ultimate strength behavior of long-span cable-stayed bridge was developed. 19 refs., 17 figs., 2 tabs.

  1. An Optimization Algorithm for the Design of an Irregularly-Shaped Bridge Based on the Orthogonal Test and Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Hanbing Liu

    2016-11-01

    Full Text Available Irregularly-shaped bridges are usually adopted to connect the main bridge and ramps in urban overpasses, which are under significant flexion-torsion coupling effects and in complicated stress states. In irregular-shaped bridge design, the parameters such as ramp radius, bifurcation diaphragm stiffness, box girder height, and supporting condition could affect structural performance in different manners. In this paper, the influence of various parameters on three indices, including maximum stress, the stress variation coefficient, and the fundamental frequency of torsional vibration, is investigated and analyzed based on orthogonal test method. Through orthogonal analysis, the major influence parameters and corresponding optimal values for these indices are achieved. Combining with the analytic hierarchy process (AHP, the hierarchical structure model of the multi-indices orthogonal test is established and a comprehensive weight analysis method is proposed to reflect the parameter influence on overall mechanical properties of an irregularly-shaped bridge. Influence order and optimal values of parameters for overall mechanical properties are determined based on the weight of factors and levels calculated by the comprehensive weight analysis method. The results indicate that the comprehensive weight analysis method is superior to the overall balance method, which verifies the effectiveness and accuracy of the comprehensive weight analysis in the parameter optimization of the multi-indices orthogonal test for an irregularly-shaped bridge. Optimal parameters obtained in this paper can provide reference and guidance for parameter control in irregularly-shaped bridge design.

  2. Bridges analysis, design, structural health monitoring, and rehabilitation

    CERN Document Server

    Bakht, Baidar

    2015-01-01

    This book offers a valuable guide for practicing bridge engineers and graduate students in structural engineering; its main purpose is to present the latest concepts in bridge engineering in fairly easy-to-follow terms. The book provides details of easy-to-use computer programs for: ·      Analysing slab-on-girder bridges for live load distribution. ·      Analysing slab and other solid bridge components for live load distribution. ·      Analysing and designing concrete deck slab overhangs of girder bridges under vehicular loads. ·      Determining the failure loads of concrete deck slabs of girder bridges under concentrated wheel loads. In addition, the book includes extensive chapters dealing with the design of wood bridges and soil-steel bridges. Further, a unique chapter on structural health monitoring (SHM) will help bridge engineers determine the actual load carrying capacities of bridges, as opposed to their perceived analytical capacities. The chapter addressing structures...

  3. Fatigue of cable anchorage of large cable stayed bridge; Daikibo shachokyo cable teichaku kozo no hiro

    Energy Technology Data Exchange (ETDEWEB)

    Endo, T.; Matsumoto, T. [Honshu-Shikoku Bridge Authority, Tokyo (Japan); Tsukahara, H. [Yokogawa Bridge Corp., Tokyo (Japan); Miki, C. [Tokyo Institute of Technology, Tokyo (Japan)

    1995-10-21

    Design considerations such as design schemes, the assemblage and welding of steel plates, and safety for fatigue of welded connections have to be taken for the cable anchorages of the steel cable stayed bridges. In this study, two full scale models, which have different shape of box anchorages welded to the web of the main girder, were made to investigate fatigue characteristics as well as assemblage of plate and gelding details. Finite element analyses for both test models and actual bridges here carried out to compare stress distribution. It was confirmed that the assemblage and welding of both types of box anchorage were attainable kith required quality and accuracy. According to the fatigue test, fatigue cracks originated from the weldings of the bearing plate to which the load from cable socket applied directly were caused by out-of-plane bending of the bearing plate. It was proved that the slight modifications of the details around the bearing plate resulted in sufficient fatigue strength in both types of anchorage. 1 ref., 23 figs., 2 tabs.

  4. Characterization of track geometric imperfections leading to maximal dynamic amplification of internal forces in railway bridges

    Directory of Open Access Journals (Sweden)

    P. G. C. Amaral

    Full Text Available ABSTRACT This paper resorts to a simplified dynamic analysis methodology for the study of vibrations in railway bridges produced by the passage of a typical passenger train, or EUT (Electric Unit Train. It starts from a model with fifteen degrees-of-freedom, namely vertical (bounce and horizontal displacements (sway and rotations about the longitudinal (roll, transverse (pitch and vertical (yaw axes. In this methodology, dynamic models of the train and the bridge are assumed to be initially uncoupled, yet being bound by the interaction train-bridge forces. Thus, the loads are evaluated for the train running on a rigid and fixed deck, considering geometric irregularities, different for each rail line, in both the vertical and horizontal track planes, as well as in the wheels. The contact forces are statically condensed at the vehicle’s centre of gravity and applied on a simplified 3D beam model. To represent the train passage over the bridge, functions are used to describe the interaction forces at each node of the beam model, as time evolves. Thus, it is possible to identify the dynamic response caused by the geometric irregularities and also evaluate the dynamic amplification obtained for any internal force, which is compared to the impact coefficient proposed by the Brazilian standards for the design of railway bridges (NBR 7187, used in quasi-static analysis. For the sake of an illustration, a thirty-six-metre-span concrete bridge with box girder section was considered. A study was carried out to find out the parameters of the irregularity functions that could potentially lead to maximal amplification of internal forces in the bridge.

  5. Virtual box

    DEFF Research Database (Denmark)

    Stougaard, Malthe Kirkhoff

    2007-01-01

    . This paper reports on the design, implementation and initial evaluation of Virtual Box. Virtual Box attempts to create a physical and engaging context in order to support reciprocal interactions with expressive content. An implemented version of Virtual Box is evaluated in a location-aware environment...

  6. Stochastic finite element analysis of long-span bridges with CFRP ...

    Indian Academy of Sciences (India)

    are represented by 139 beam elements, the cable stays are modelled with 30 truss elements. The stiffening girder and the towers of the Jindo Bridge were made of steel (Tappin & Clark. 1985). For the purpose of discussion, a same span length of cable-stayed bridge with CFRP stay cables is schemed. Except for the ...

  7. Strengthening Bridges with Prestressed CFRP Strips

    Science.gov (United States)

    Siwowski, Tomasz; Żółtowski, Piotr

    2012-06-01

    Limitation of bridge's carrying bearing capacity due to aging and deterioration is a common problem faced by road administration and drivers. Rehabilitation of bridges including strengthening may be applied in order to maintain or upgrade existing bridge parameters. The case studies of strengthening of two small bridges with high modulus prestressed CFRP strips have been presented in the paper. The first one - reinforced concrete slab bridge - and the other - composite steel-concrete girder bridge - have been successfully upgraded with quite new technology. In both cases the additional CFRP reinforcement let increasing of bridge carrying capacity from 15 till 40 metric tons. The CFRP strip prestressing system named Neoxe Prestressing System (NPS), developed by multi-disciplinary team and tested at full scale in Rzeszow University of Technology, has been also described in the paper.

  8. Bento Boxes

    Science.gov (United States)

    Hasio, Cindy

    2010-01-01

    Bento boxes are common objects in Japanese culture, designed to hold enough lunch for one person. They have individual compartments and sometimes multiple tiers for rice, vegetables, and other side dishes. They are made of materials ranging from wood, cloth, aluminum, or plastic. In general, the greater the number of foods, the better the box is…

  9. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N⁴-methyl-3-thiosemicarbazone: crystal structure of a novel sulfur bridged copper(II) box-dimer.

    Science.gov (United States)

    Jayakumar, K; Sithambaresan, M; Aiswarya, N; Kurup, M R Prathapachandra

    2015-03-15

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ=0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g||>g⊥>2.0023 and the g values in frozen DMF are consistent with the d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

    Science.gov (United States)

    Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

    2015-03-01

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

  11. Random Young diagrams in a Rectangular Box

    DEFF Research Database (Denmark)

    Beltoft, Dan; Boutillier, Cédric; Enriquez, Nathanaël

    We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape.......We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape....

  12. Geometric Nonlinear Analysis of Self-Anchored Cable-Stayed Suspension Bridges

    Directory of Open Access Journals (Sweden)

    Wang Hui-Li

    2013-01-01

    Full Text Available Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  13. Geometric nonlinear analysis of self-anchored cable-stayed suspension bridges.

    Science.gov (United States)

    Hui-Li, Wang; Yan-Bin, Tan; Si-Feng, Qin; Zhe, Zhang

    2013-01-01

    Geometric nonlinearity of self-anchored cable-stayed suspension bridges is studied in this paper. The repercussion of shrinkage and creep of concrete, rise-to-span ratio, and girder camber on the system is discussed. A self-anchored cable-stayed suspension bridge with a main span of 800 m is analyzed with linear theory, second-order theory, and nonlinear theory, respectively. In the condition of various rise-to-span ratios and girder cambers, the moments and displacements of both the girder and the pylon under live load are acquired. Based on the results it is derived that the second-order theory can be adopted to analyze a self-anchored cable-stayed suspension bridge with a main span of 800 m, and the error is less than 6%. The shrinkage and creep of concrete impose a conspicuous impact on the structure. And it outmatches suspension bridges for system stiffness. As the rise-to-span ratio increases, the axial forces of the main cable and the girder decline. The system stiffness rises with the girder camber being employed.

  14. Wave induced extreme hull girder loads on containerships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Pedersen, Preben Terndrup; Shi, Bill

    2009-01-01

    This paper provides simple but rational procedures for prediction of extreme wave – induced sectional hull girder forces with reasonable engineering accuracy. The procedures take into account main ship hull characteristics such as: length, breadth, draught, block coefficient, bow flare coefficient......, forward speed and hull flexibility. The vertical hull girder loads are evaluated for specific operational profiles. Firstly a quadratic strip theory is presented which can give separate predictions for the hogging and sagging bending moments and shear forces and for hull girder loads. Then this procedure...... is based on rational methods it can be applied for novel single hull ship types not presently covered by the rules of the classification societies or to account for specific operational profiles....

  15. Bridge and steel structures. History and vision on bridge erection; Kyoryo kokozobutsu. Kasetsu gijutsu no shorai

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, S.; Hayashi, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1998-08-20

    This paper describes the progress of bridge erection technology. It introduces the results of cable erection, rotated/extruded erection, and cantilever erection. The cable erection is a multi point suspension erection using cables. For the rotated/extruded erection, the monolithic construction is conducted on a working yard set in a right angle to the construction position, and the horizontal beams of the bridge piers (corbel girders) are constructed by the rotated method using a slewing base incorporated around the bridge piers at one side. For the construction of stiffening girders of Innoshima-ohashi Bridge of Honshu-Shikoku Joint Bridge in 1978, trussed face bar blocks were extruded from the main tower in order using a travel crane. For the suspension bridges and cable stayed bridges, main towers were erected using various types of cranes. The erection of Tamashima-ohashi Bridge with a weight of 500 ton using an offshore floating crane is introduced as a large block method. Analysis methods and measurement techniques at the site are used in order to analyze the shape in each step under the erection and to ensure the accurate final complete shape. Reduction of the construction cost, improvement of erection technology, and technology development for large-scale projects are subjects in the future. 22 refs., 8 figs., 1 tab.

  16. A Damage Prognosis Method of Girder Structures Based on Wavelet Neural Networks

    Directory of Open Access Journals (Sweden)

    Rumian Zhong

    2014-01-01

    Full Text Available Based on the basic theory of wavelet neural networks and finite element model updating method, a basic framework of damage prognosis method is proposed in this paper. Firstly, a damaged I-steel beam model testing is used to verify the feasibility and effectiveness of the proposed damage prognosis method. The results show that the predicted results of the damage prognosis method and the measured results are very well consistent, and the maximum error is less than 5%. Furthermore, Xinyihe Bridge in the Beijing-Shanghai Highway is selected as the engineering background, and the damage prognosis is conducted based on the data from the structural health monitoring system. The results show that the traffic volume will increase and seasonal differences will decrease in the next year and a half. The displacement has a slight increase and seasonal characters in the critical section of mid span, but the strain will increase distinctly. The analysis results indicate that the proposed method can be applied to the damage prognosis of girder bridge structures and has the potential for the bridge health monitoring and safety prognosis.

  17. Evaluating the time-dependent and bond characteristics of lightweight concrete mixes for Kansas prestressed concrete bridges : technical summary.

    Science.gov (United States)

    2011-07-01

    The majority of the bridges in Kansas are in rural areas. Many of these are : becoming structurally deficient, and are in need of replacement. Due to the location of : these bridges, cost of transporting prestressed girders to these areas often makes...

  18. Study on safety level of RC beam bridges under earthquake

    Science.gov (United States)

    Zhao, Jun; Lin, Junqi; Liu, Jinlong; Li, Jia

    2017-08-01

    This study considers uncertainties in material strengths and the modeling which have important effects on structural resistance force based on reliability theory. After analyzing the destruction mechanism of a RC bridge, structural functions and the reliability were given, then the safety level of the piers of a reinforced concrete continuous girder bridge with stochastic structural parameters against earthquake was analyzed. Using response surface method to calculate the failure probabilities of bridge piers under high-level earthquake, their seismic reliability for different damage states within the design reference period were calculated applying two-stage design, which describes seismic safety level of the built bridges to some extent.

  19. Evaluation of a bridge using simplified element modeling

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R. [Los Alamos National Lab., NM (United States); Duffey, T.A. [New Mexico Highlands Univ., Las Vegas, NM (United States)

    1995-02-01

    An experimental-numerical comparison of the forced and ambient vibrations Of a multi-span composite plate-girder bridge was performed. The bridge was modeled using a finite element program at three levels of complexity, including a simple 250 DOF model that utilizes a single beam element to represent the entire bridge cross section. Difficulties encountered in the development of the simple model are discussed. The dynamic properties predicted by the simple model were consistent with these measured on the bridge and computed using more detailed finite element models.

  20. Structural evaluation of LIC-310-0396 and FAY-35-17-6.82 box beams with advanced strand deterioration : executive summary report.

    Science.gov (United States)

    2011-09-01

    Adjacent prestressed concrete box beam bridges are popular in Ohio with approximately 1,100 bridges existing that are under ODOT maintenance responsibility, amounting to approximately 9% of all Ohios bridges. However, these bridges are also very c...

  1. Design and construction of the Natorigawa Bridge; Natorigawa kyoryo no sekkei/seko

    Energy Technology Data Exchange (ETDEWEB)

    Murai, Y.; Oba, M.; Omurata, Y. [JR East Japan Railway Co., Tokyo (Japan); Miyauchi, M.; Iwasaki, I. [Taisei Corp., Tokyo (Japan)

    1997-03-31

    The Natorigawa Bridge is reconstructed. Out of the reconstruction work, a report is made mainly on the design of the superstructure work of the PC panel-stayed bridge and the details of the work. In selecting bridge type, PC simple through beam bridge, steel trussed bridge, PC cable-stayed bridge, and PC panel-stayed bridge are compared, and a 2-span continuous PC panel-stayed bridge is adopted. Its appearance resembles that of the cable-stayed bridge, but the structure resembles a girder bridge. The appropriate span length is the intermediate range between those of the girder bridge and the cable-stayed bridge. Its trafficability is excellent with little deformation by the running of trains because the main beam, diagonal panel, and the main tower are connected rigidly to provide high rigidity of the entire bridge. PRC structure is employed in consideration of the restriction to beam height and economical efficiency. Analyses by a FEM model using two dimensional plane elements and by a few plane frame models as well as comparison of sectional force are performed for this bridge, and a proper plane model is selected. Substructure work, superstructure work and measurement work are described. 3 refs., 16 figs., 6 tabs.

  2. Response analysis of curved bridge with unseating failure control system under near-fault ground motions

    Science.gov (United States)

    Zuo, Ye; Sun, Guangjun; Li, Hongjing

    2018-01-01

    Under the action of near-fault ground motions, curved bridges are prone to pounding, local damage of bridge components and even unseating. A multi-scale fine finite element model of a typical three-span curved bridge is established by considering the elastic-plastic behavior of piers and pounding effect of adjacent girders. The nonlinear time-history method is used to study the seismic response of the curved bridge equipped with unseating failure control system under the action of near-fault ground motion. An in-depth analysis is carried to evaluate the control effect of the proposed unseating failure control system. The research results indicate that under the near-fault ground motion, the seismic response of the curved bridge is strong. The unseating failure control system perform effectively to reduce the pounding force of the adjacent girders and the probability of deck unseating.

  3. Wind tunnel experiments on unstable self-excited vibration of sectional girders

    Science.gov (United States)

    Král, Radomil; Pospíšil, Stanislav; Náprstek, Jiří

    2014-01-01

    In this paper, a wind tunnel analysis of two degrees-of-freedom system represented by sectional girders is carried out. Besides an evaluation of the aeroelastic coefficients, the analysis is focused on the influence of the natural frequency ratio on the initiation of unstable vibration, which can be of practical interest. On the phenomenological level, the paper also discusses experimentally ascertained response regimes, with an emphasis on their stability character. The attention is paid to the memory effect in the response described by the hysteresis loop together with the separation curves determining the stability boundaries. The influence of initial disturbance on the stability is examined. Two types of cross-sections were investigated: (i) rectangular one with the aspect ratio 1:5, and (ii) bridge-like cross-section with comparable principal dimensions. For both types of cross-sections, the limits of the stability are significantly affected by an intentionally introduced initial disturbance. This holds especially with regard to the rectangular profile where the separation curves create very narrow sub-domains between a stable and an unstable response, while the bridge-like cross-section demonstrates much stable behaviour.

  4. Implementation of Full-Width Bridge Deck Panels: A Synthesis Study

    OpenAIRE

    Versace, Jose David; Ramirez, J.A. [UNESP

    2004-01-01

    In this synthesis study, information related to full-depth precast deck systems has been collected and analyzed in order to facilitate implementation of full-depth precast deck systems in the state of Indiana. Nine full-depth precast deck systems were identified in the literature review. For girder bridges or similar, a full-depth precast, prestressed deck system (New England Region System) is recommended to be implemented. For bridges with decks spanning in the longitudinal direction, where ...

  5. Seismic Behavior of RNC-Isolated Bridges: A Comparative Study under Near-Fault, Long-Period, and Pulse-Like Ground Motions

    Directory of Open Access Journals (Sweden)

    Mohammed Ismail

    2016-01-01

    Full Text Available This paper introduces a recent seismic isolation system, named Roll-in-Cage (RNC isolator, for efficient protection of bridges against destructive earthquakes. The RNC isolator is a rolling-based isolation system with several integrated features in a single unit providing all the necessary functions of vertical rigid support, horizontal flexibility, full stability, hysteretic energy dissipation, and resistance to minor vibration loads. Besides, it is distinguished by a self-stopping (buffer mechanism to limit the peak bearing displacement under abrupt severe excitations, a linear gravity-based self-recentering mechanism to prevent permanent dislocations after excitations, and a notable resistance to axial tension. A three-span box-girder prestressed concrete bridge is investigated under a set of different destructive real and synthetic earthquakes including near-fault, long-period, and pulse-like ground motions. As a performance measure, the responses of isolated and nonisolated cases are compared. In addition, the RNC isolator’s behavior is then compared with those of other isolation systems including HDB, FPS, and LRB. The results confirmed that the RNC isolator has a superior behavior in achieving a balance between the peak displacements and accelerations of the isolated deck, relative other isolation systems, besides being the most (relatively efficient isolator in the great majority of studies performed.

  6. Application of Composite Structures in Bridge Engineering. Problems of Construction Process and Strength Analysis

    Science.gov (United States)

    Flaga, Kazimierz; Furtak, Kazimierz

    2015-03-01

    Steel-concrete composite structures have been used in bridge engineering from decades. This is due to rational utilisation of the strength properties of the two materials. At the same time, the reinforced concrete (or prestressed) deck slab is more favourable than the orthotropic steel plate used in steel bridges (higher mass, better vibration damping, longer life). The most commonly found in practice are composite girder bridges, particularly in highway bridges of small and medium spans, but the spans may reach over 200 m. In larger spans steel truss girders are applied. Bridge composite structures are also employed in cable-stayed bridge decks of the main girder spans of the order of 600, 800 m. The aim of the article is to present the cionstruction process and strength analysis problems concerning of this type of structures. Much attention is paid to the design and calculation of the shear connectors characteristic for the discussed objects. The authors focused mainly on the issues of single composite structures. The effect of assembly states on the stresses and strains in composite members are highlighted. A separate part of problems is devoted to the influence of rheological factors, i.e. concrete shrinkage and creep, as well as thermal factors on the stresses and strains and redistribution of internal forces.

  7. Experiments and theory on deck and girder crushing

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup; Ocakli, Hasan

    1999-01-01

    This paper is concerned with theoretical and experimental analysis of deep plastic collapse of a deck or deep girder subjected to an in-plane, concentrated load. A theory is derived which is valid until initition of fracture in the structure. The presented experimental results show load-deflection...... curves and modes of deformation for decks, stringer decks and deep thin-walled beams subjected to central or excentric point loads between transverse frames. Based on theory and experiments, various modelling aspects of the local/global failure of the beams are discussed. The agreement between...

  8. Procurement of Beams in Multiple D&B Bridge Projects

    Directory of Open Access Journals (Sweden)

    CT. Ramanathan

    2010-06-01

    Full Text Available Selected infrastructure development projects are being implemented by Design and Build (D&B pocurement system in Sabah (East Malaysia by the Public Works Department (PWD. In the first phase 45 bridge replacement projects were awarded in 5 packages. These simultaneous multiple Bridge projects are for the development of the backward areas and hence their timely completion is utmost important. Procurement and production of bridge beams have been the critical element of construction in these rural areas and no researches has been reported on various aspects of procurement of the bridge beams in multiple D&B projects. The aspects of procurement researched in this work include the determination of a common beam element for the ease of procurement and the optimization of the construction methodology, the finalization and purchasing plate dimensions to suite the manufacturer's production range, the delivery of materials, the planning and monitoring of fabrication, the preparation and assembly, and the erection and launching of beams. The beams are optimized using element optimization techniques. The most important problems in fabricating steel girders were in planning and scheduling of materials for the fabrication and the fabrication process. Findings in all the aspects of production of steel girders are highlighted through a case study of six long span bridges at various locations in Sabah. Solutions drawn from lessons learnt which minimize wastages, and aids in timely completion of beams in multiple bridge construction are discussed.

  9. Computer modeling of road bridge for simulation moving load

    Directory of Open Access Journals (Sweden)

    Miličić Ilija M.

    2016-01-01

    Full Text Available In this paper is shown computational modelling one span road structures truss bridge with the roadway on the upper belt of. Calculation models were treated as planar and spatial girders made up of 1D finite elements with applications for CAA: Tower and Bridge Designer 2016 (2nd Edition. The conducted computer simulations results are obtained for each comparison of the impact of moving load according to the recommendations of the two standards SRPS and AASHATO. Therefore, it is a variant of the bridge structure modeling application that provides Bridge Designer 2016 (2nd Edition identical modeled in an environment of Tower. As important information for the selection of a computer applications point out that the application Bridge Designer 2016 (2nd Edition we arent unable to treat the impacts moving load model under national standard - V600. .

  10. Monitoring Bridge Dynamic Responses Using Fiber Bragg Grating Tiltmeters.

    Science.gov (United States)

    Xiao, Feng; Chen, Gang S; Hulsey, J Leroy

    2017-10-20

    In bridge health monitoring, tiltmeters have been used for measuring rotation and curvature; however, their application in dynamic parameter identification has been lacking. This study installed fiber Bragg grating (FBG) tiltmeters on the bearings of a bridge and monitored the dynamic rotational angle. The dynamic features, including natural frequencies and mode shapes, have been identified successfully. The innovation presented in this paper is the first-time use of FBG tiltmeter readings to identify the natural frequencies of a long-span steel girder bridge. The identified results have been verified using a bridge finite element model. This paper introduces a new method for the dynamic monitoring of a bridge using FBG tiltmeters. Limitations and future research directions are also discussed in the conclusion.

  11. Hybrid Bridge Structures Made of Frp Composite and Concrete

    Science.gov (United States)

    Rajchel, Mateusz; Siwowski, Tomasz

    2017-09-01

    Despite many advantages over the conventional construction materials, the contemporary development of FRP composites in bridge engineering is limited due to high initial cost, low stiffness (in case of glass fibers) and sudden composite failure mode. In order to reduce the given limitations, mixed (hybrid) solutions connecting the FRP composites and conventional construction materials, including concrete, have been tested in many countries for 20 years. Shaping the hybrid structures based on the attributes of particular materials, aims to increase stiffness and reduce cost without losing the carrying capacity, lightness and easiness of bridges that includes such hybrid girders, and to avoid the sudden dangerous failure mode. In the following article, the authors described examples of hybrid road bridges made of FRP composite and concrete within the time of 20 years and presented the first Polish hybrid FRP-concrete road bridge. Also, the directions of further research, necessary to spread these innovative, advanced and sustainable bridge structures were indicated.

  12. An influence of technological contraflexure of crane bridges on its durability

    Directory of Open Access Journals (Sweden)

    Artur BLUM

    2010-01-01

    Full Text Available Standard requirements till 1996 year during bridge crane manufacturing demanded a positive technological contraflexure. As a result of this process were implemented technological compressive stress into tensile zone from inertial and operational loads and tensile stress into compressive zone. This way there were redistributed resultant stress which have increased fatigue strength of exploited crane bridges. Actually valid standard PN-ISO 7363 has removed this obligatory requirement. Its use depends of crane buyer demands. Reduction of initial positive deflection can be seen after few years of crane operations. It is a case of girders permanent deflections increment. Article presents method of technological prestressing of bridge girders with its practical application to obtain positive contrafexure.

  13. Discrete vortex method simulations of aerodynamic admittance in bridge aerodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Johannes Tophøj; Hejlesen, Mads Mølholm; Larsen, Allan

    , and to determine aerodynamic forces and the corresponding flutter limit. A simulation of the three-dimensional bridge responseto turbulent wind is carried out by quasi steady theory by modelling the bridge girder as a line like structure [2], applying the aerodynamic load coefficients found from the current version...... of DVMFLOW in a strip wise fashion. Neglecting the aerodynamic admittance, i.e. the correlation of the instantaneous lift force to the turbulent fluctuations in the vertical velocities, leads to higher response to high frequency atmospheric turbulence than would be obtained from wind tunnel tests....

  14. Investigation of aerodynamic stability by wind response observation during cantilever construction of the Ikara Ohashi bridge; Ikara Ohashi haridashi sekoji no kaze kansoku ni yoru taifu anteisei no kento

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Mukai, H.; Takeda, T. [Kajima Corp., Tokyo (Japan)

    1995-12-20

    In order to ensure aerodynamic stability during cantilever construction of the Ikara Ohashi Bridge, wind response observation was carried out and discussions were given on the result. The Ikara Ohashi Bridge is a 5-span continuous PC cable-stayed bridge with the central span being a concrete bridge having a length of 260 m, which is the longest in Japan. The bridge was constructed using a method that main girders are extended from the central tower to the right and left sides while the girders are stayed by bracing cables. The bridge construction site is in an area which is often subjected to typhoons and gusts like seasonal winds in winter, hence a discussion on aerodynamic stability of the bridge especially during extension work was viewed as an important matter. In addition, the construction used two small-capacity cables spaced and bundled as the bracing material, which required verification on their aerodynamic stability. In order to identify vibration characteristics of the main girders and the central tower, wind response observation has been performed as soon as the construction was begun. As a result, the vibration characteristics of the main girders and the central tower were identified, and it was verified that vibration shape and dominant frequency can be evaluated properly by an intrinsic value analysis that uses a multi-material point frame model. Furthermore, effects of different vibration absorbing measures were compared, and the effective methods were adopted as the result. 4 refs., 12 figs.

  15. Field performance of timber bridges. 9, Big Erick`s stress-laminated deck bridge

    Science.gov (United States)

    J. A. Kainz; J. P. Wacker; M. Nelson

    The Big Erickas bridge was constructed during September 1992 in Baraga County, Michigan. The bridge is 72 ft long, 16 ft wide, and consists of three simple spans: two stress-laminated deck approach spans and a stress-laminated box center span. The bridge is unique in that it is one of the first known stress-laminated timber bridge applications to use Eastern Hemlock...

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

    OpenAIRE

    Zeng, Zhiping; Zhu, Kunteng; He, Xianfeng; Xu, Wentao; Chen, Lingkun; Lou, Ping

    2015-01-01

    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 i...

  17. Structural behavior of suspension bridge with a stabilizing cable

    Directory of Open Access Journals (Sweden)

    Konovalov Anatoliy

    2017-01-01

    Full Text Available Suspended structures are commonly used in construction of motorway and pedestrian bridges. These structures allow wide spans without the need for intermediate supports. Suspension bridges are noted for lower structural stiffness as compared to beam bridges and arc bridges. The stiffness control depending on the environment and external effects (moving loads, wind, seismic forces, etc. is a real-life challenge [1, 2]. The authors of this paper have evaluated the use of stabilizing cable installed in the central span under the stiffening girder as the means of stiffness control. A plane 3D model of a suspension bridge was developed using the ANSYS software. The study compared the stress deformed state and dynamic properties of the models with and without a stabilizing cable. The displacement in the model equipped with a stabilizing cable, as compared to the one without, was noted to be lower in all relevant sections: 2.6 times in the middle of the central span of the stiffening girder; 15 times in the middle of the end span; and displacement of the tower top was 3.5 times lower.

  18. Guidelines for design and safe handling of curved I-shaped steel girders.

    Science.gov (United States)

    2010-02-01

    The purpose of this set of guidelines is to summarize recommendations from work : completed as part of the Texas Department of Transportation (TxDOT) Research Project 0-5574 : entitled "Curved Plate Girder Design for Safe and Economic Construction." ...

  19. Fatigue and shear behavior of HPC bulb tee girders : LTRC technical summary report.

    Science.gov (United States)

    2008-04-01

    The objectives of the research were (1) to provide assurance that full size, deep prestressed concrete girders made with HPC would perform satisfactorily under flexural fatigue, static shear, and static flexural loading conditions; (2) to determine i...

  20. 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...

  1. Myocardial Bridge

    Science.gov (United States)

    ... Sudden Cardiac Arrest Valve Disease Vulnerable Plaque Myocardial Bridge Related terms: myocardium, coronary arteries, myocardial ischemia Your ... surface of the heart. What is a myocardial bridge? A myocardial bridge is a band of heart ...

  2. Dynamic response for structural health monitoring of the Penang (I) cable-stayed bridge

    Science.gov (United States)

    Mohammed, M. I.; Sulaeman, E.; Mustapha, F.

    2017-03-01

    The paper discusses the dynamic response of the Penang (I) cable stayed bridge structure under various moving load representing typical traffic load of the bridge. The bridge has a total span of 440 m excluding the transition bridge that assumed to be not connected structurally to the main bridge structure. The bridge that links the fast growing Pinang Island and the Malaysian Mainland Peninsula has been known to be fully utilized which leads to the construction of Penang (II) bridge and now the third one. Due to highly traffic use of the bridge that may lead to reduction of the bridge design life, the dynamic response of the bridge becomes important to predict critical part of the bridge structure elements including the main girder and the 144 stay cables. The present study reveals that, due to flexible nature of the cable stayed bridge, the moving load that interacts with the natural dynamic characteristics of the bridge, gives significant stress increment compare to proportional static load especially when the moving load is un-symmetric. For this reason, several classes of typical vehicle passing the bridge with various vehicle speeds are investigated to demonstrate their effect on the bridge displacement, internal forces and stresses. The results can be used for further fatigue assessment of the bridge.

  3. Yonjung High-Speed Railway Bridge Assessment Using Output-Only Structural Health Monitoring Measurements under Train Speed Changing

    Directory of Open Access Journals (Sweden)

    Mosbeh R. Kaloop

    2016-01-01

    Full Text Available Yonjung Bridge is a hybrid multispan bridge that is designed to transport high-speed trains (HEMU-430X with maximum operating speed of 430 km/h. The bridge consists of simply supported prestressed concrete (PSC and composite steel girders to carry double railway tracks. The structural health monitoring system (SHM is designed and installed to investigate and assess the performance of the bridge in terms of acceleration and deformation measurements under different speeds of the passing train. The SHM measurements are investigated in both time and frequency domains; in addition, several identification models are examined to assess the performance of the bridge. The drawn conclusions show that the maximum deflection and acceleration of the bridge are within the design limits that are specified by the Korean and European codes. The parameters evaluation of the model identification depicts the quasistatic and dynamic deformations of PSC and steel girders to be different and less correlated when higher speeds of the passing trains are considered. Finally, the variation of the frequency content of the dynamic deformations of the girders is negligible when high speeds are considered.

  4. Onboard monitoring of fatigue damage rates in the hull girder

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam; Jensen, Jørgen Juncher; Pedersen, Preben Terndrup

    2011-01-01

    Most new advanced ships have extensive data collection systems to be used for continuous monitoring of engine and hull performance, for voyage performance evaluation etc. Such systems could be expanded to include also procedures for stress monitoring and for decision support, where the most...... critical wave-induced ship extreme responses and fatigue damage accumulation can be estimated for hypothetical changes in ship course and speed in the automatically estimated wave environment.The aim of this paper is to outline a calculation procedure for fatigue damage rate prediction in hull girders......-induced stress ranges in a container ship, where the associated fatigue damage rates calculated from a combination of the rain-flow counting method and the Palmgren-Miner damage rule are compared with damage predictions obtained from a computationally much faster frequency fatigue analysis using a spectral...

  5. Estimation of Curvature Changes for Steel-Concrete Composite Bridge Using Fiber Bragg Grating Sensors

    Directory of Open Access Journals (Sweden)

    Donghoon Kang

    2013-01-01

    Full Text Available This study is focused on the verification of the key idea of a newly developed steel-concrete composite bridge. The key idea of the proposed bridge is to reduce the design moment by applying vertical prestressing force to steel girders, so that a moment distribution of a continuous span bridge is formed in a simple span bridge. For the verification of the key technology, curvature changes of the bridge should be monitored sequentially at every construction stage. A pair of multiplexed FBG sensor arrays is proposed in order to measure curvature changes in this study. They are embedded in a full-scale test bridge and measured local strains, which are finally converted to curvatures. From the result of curvature changes, it is successfully ensured that the key idea of the proposed bridge, expected theoretically, is viable.

  6. Experimental Investigation for Behavior of Spliced Continuous RC Girders Strengthened with CFRP Laminates

    Directory of Open Access Journals (Sweden)

    Ammar Yasir Ali

    2016-03-01

    Full Text Available In this paper, the behavior of spliced continuous reinforced concrete girders was experimentally investigated. The main objective was to examine the contribution of the carbon fiber reinforced polymer (CFRP laminates in strengthening the spliced continuous reinforced concrete girders. Eight models of continuous reinforced concrete girder were constructed and tested. The test variables were strengthening the splice joints by different schemes of CFRP laminates, presence of horizontal stirrups through the interfaces of the joints and using binder material at the interfaces of the joints. The results showed that strengthening the continuous spliced girders with 45° inclined CFRP laminates led to an increase in the ultimate load in a range of (47 to 74%. Besides, strengthening the continuous spliced girder with horizontal CFRP laminates bonded at its lateral faces could increase the ultimate load by 70%. Additionally, the ultimate load of the continuous spliced girder was increased by (30% due to presence of the horizontal steel stirrups through the interfaces of the joints

  7. Nonlinear Analysis of Spliced Continuous RC Girders Strengthened with (CFRP Laminates using ANSYS

    Directory of Open Access Journals (Sweden)

    Ammar Yasir Ali

    2016-03-01

    Full Text Available This paper presents the details of the finite element analysis of spliced continuous reinforced concrete girders. Five spliced continuous girders and one non-spliced continuous girder were analyzed using the ANSYS program. Each spliced girder consisted of three precast segments spliced at two cast-in-place joints at the inflection points, using splices of hooked dowels. Three spliced girders were strengthened using different schemes of the carbon fiber reinforced polymer (CFRP laminates. The concrete was modeled using (SOLID65 eight-node brick element and the steel reinforcement was modeled discretely using (LINK8 spar element. The straight parts of the spliced bars were modeled using discrete representation with interface elements using (COMBIN39 elements to represent the bond-slip behavior while the hooked part of each spliced bar was replaced by a single spring element. The CFRP laminates were modeled using (SHELL41 shell element. The interfaces between the precast concrete segments and the joints were modeled using CONTAC52 interface elements in conjunction with vertical spring elements to represent the dowel action of the steel bars that crossing the interfaces. The ANSYS model succeeded to an acceptable degree in predicting the structural behavior of the analyzed spliced girders with average of differences of about 6% between the predicted and experimental ultimate load.

  8. I-5/Gilman advanced technology bridge project

    Science.gov (United States)

    Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

    2000-04-01

    The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

  9. Research on Collapse Process of Cable-Stayed Bridges under Strong Seismic Excitations

    Directory of Open Access Journals (Sweden)

    Xuewei Wang

    2017-01-01

    Full Text Available In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM, and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

  10. Random vibration analysis of train-bridge under track irregularities and traveling seismic waves using train-slab track-bridge interaction model

    Science.gov (United States)

    Zeng, Zhi-Ping; Zhao, Yan-Gang; Xu, Wen-Tao; Yu, Zhi-Wu; Chen, Ling-Kun; Lou, Ping

    2015-04-01

    The frequent use of bridges in high-speed railway lines greatly increases the probability that trains are running on bridges when earthquakes occur. This paper investigates the random vibrations of a high-speed train traversing a slab track on a continuous girder bridge subjected to track irregularities and traveling seismic waves by the pseudo-excitation method (PEM). To derive the equations of motion of the train-slab track-bridge interaction system, the multibody dynamics and finite element method models are used for the train and the track and bridge, respectively. By assuming track irregularities to be fully coherent random excitations with time lags between different wheels and seismic accelerations to be uniformly modulated, non-stationary random excitations with time lags between different foundations, the random load vectors of the equations of motion are transformed into a series of deterministic pseudo-excitations based on PEM and the wheel-rail contact relationship. A computer code is developed to obtain the time-dependent random responses of the entire system. As a case study, the random vibration characteristics of an ICE-3 high-speed train traversing a seven-span continuous girder bridge simultaneously excited by track irregularities and traveling seismic waves are analyzed. The influence of train speed and seismic wave propagation velocity on the random vibration characteristics of the bridge and train are discussed.

  11. Study and application of micrometric alignment on the prototype girders of the CLIC Two-Beam Module

    CERN Document Server

    Gazis, Nikolaos; Mainaud-Durand, Hélène; Samochkine, Alexandre; Anastasopoulos, Michail

    2011-01-01

    The Compact LInear Collider (CLIC), currently under study at CERN, aims at the development of a Multi-TeV e+ e- collider. The micro-precision CLIC RF-structures will have an accelerating gradient of 100 MV/m and will be mounted and aligned on specially developed supporting girders. The girder fabrication constraints are dictated by stringent physics requirements. The micrometric pre-alignment over several kilometers of girders, allow for the CLIC structures to fulfill their acceleration and collision functionality. Study of such girders and their sophisticated alignment method, is a challenging case involving dedicated mechanical design as well as prototype production and experimental testing.

  12. Wireless Smart Sensor Network System Using SmartBridge Sensor Nodes for Structural Health Monitoring of Existing Concrete Bridges

    Science.gov (United States)

    Gaviña, J. R.; Uy, F. A.; Carreon, J. D.

    2017-06-01

    There are over 8000 bridges in the Philippines today according to the Department of Public Works and Highways (DPWH). Currently, visual inspection is the most common practice in monitoring the structural integrity of bridges. However, visual inspections have proven to be insufficient in determining the actual health or condition of a bridge. Structural Health Monitoring (SHM) aims to give, in real-time, a diagnosis of the actual condition of the bridge. In this study, SmartBridge Sensor Nodes were installed on an existing concrete bridge with American Association of State Highway and Transportation Officials (AASHTO) Type IV Girders to gather vibration of the elements of the bridge. Also, standards on the effective installation of SmartBridge Sensor Nodes, such as location and orientation was determined. Acceleration readings from the sensor were then uploaded to a server, wherein they are monitored against certain thresholds, from which, the health of the bridge will be derived. Final output will be a portal or webpage wherein the information, health, and acceleration readings of the bridge will be available for viewing. With levels of access set for different types of users, the main users will have access to download data and reports. Data transmission and webpage access are available online, making the SHM system wireless.

  13. Static behaviors of long-span cable-stayed bridge; Chodai shachokyo no seiteki kyodo ni kansuru kosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xu [Saitama Univ., Saitama (Japan). Graduate School; Yamaguchi, H.; Ito, M. [Saitama Univ., Urawa (Japan). Faculty of Engineering

    1996-04-21

    In this study, incremental equation of cable-stayed bridge is formulated by finite element method taking the geometrical nonlinear analysis into account. Then, as an example of designing a bridge with 1500m span, setting up the initial tension, analysis of in-plane behavior caused by live loads as well as analysis of the behavior against wind caused by out-of-plane wind load that are necessary for designing a bridge with 1500m span are carried out. The main results obtained through the study are as follows. As for the cable stayed bridge with 1500m center super long-span having supplementary supporting points between the side arms, the geometrical non-linearity caused by the in-plane design live loads is not remarkable. The effects of wind which acts on girders on analysis of the behaviors against wind are different depending on the aerodynamic performance of the girder and in the case of high wind speed, strong effects on the behavior against wind of the in-plane and screws generate. As the changing of tension of the cable makes influences on the force of in-plane cross section and on displacement of the girder, if the wind speed is very high, the analysis results of the behaviors against wind of in-plane and screws of the cable-stayed bridge may be different depending on in what manner the wind load on the cable to be treated. 16 refs., 16 figs., 1 tab.

  14. STRESS-DEFORMED STATE OF A STRUT-FRAMED CRANE GIRDER

    Directory of Open Access Journals (Sweden)

    Kh. M. Muselemov

    2017-01-01

    Full Text Available Objectives. The aim of the present work is to study the influence of design parameters on the stress-deformed state of a sprengel crane girder; to compile the tables and corresponding graphs illustrating changes in internal force factors in the characteristic cross-sections of the system elements under consideration. The article describes the study of the stress-deformed state (SDS of a metal strut-framed crane girder.Methods. Numerical methods of analysis based on the use of the Green's function are used during solving this problem. A dimensionless parameter is introduced, depending on which the tables and graphs are constructed. According to the known algorithm, the calculations of internal force factors in the sections of the considered construction are performed.Results. Depending on the dimensionless parameter characterising the geometry and physical features of the system, tables of bending moments and transverse forces are compiled. According to these tables, the appropriate graphs are plotted in order to choose easily the optimal design parameters.Conclusion. The dependence of the moments and transverse forces on the dimensionless parameter k was found, the corresponding graphs were plotted and the metal costs for the girders were calculated. The minimum values of the moments and transverse forces are established to take place when the dimensionless parameter k values are close to zero. The most economical was a strut-framed crane girder having k = 0.0001. The most uneconomical had k = 0.05 and k =∞. Eventually, the sprengel girders were found to be more profitable as compared to conventional crane girders. In the examples considered in the article, the metal savings amounted up to 14%. The presented methodology allows the calculation and designing of strut-framed crane girders with two racks to be carried out. 

  15. Nonlinear Seismic Response Analysis of Curved and Skewed Bridge System with Spherical Bearings

    Directory of Open Access Journals (Sweden)

    Junwon Seo

    2013-01-01

    Full Text Available A three-dimensional (3D modeling approach to investigate nonlinear seismic response of a curved and skewed bridge system is proposed. The approach is applied to a three-span curved and skewed steel girder bridge in the United States. The superstructure is modeled using 3D frame elements for the girders, truss elements for the cross-frames, and equivalent frame elements to represent the deck. Spherical bearings are modeled with zero-length elements coupled with hysteretic material models. Nonlinear seismic responses of the bearings subjected to actual ground motions are examined in various directions. Findings indicate that the bearings experience moderate damage for most loading scenarios based on FEMA seismic performance criteria. Further, the bearing responses are different for the loading scenarios because of seismic effects caused by interactions between excitation direction and radius of curvature.

  16. Increased of the capacity integral bridge with reinforced concrete beams for single span

    Science.gov (United States)

    Setiati, N. Retno

    2017-11-01

    Sinapeul Bridge that was built in 2012 in Sumedang is a bridge type using a full integral system. The prototype of integral bridge with reinforced concrete girder and single span 20 meters until this year had decreased capacity. The bridge was conducted monitoring of strain that occurs in the abutment in 2014. Monitoring results show that based on the data recorded, the maximum strain occurs at the abutment on the location of the integration of the girder of 10.59 x 10-6 tensile stress of 0.25 MPa (smaller than 150 x 10-6) with 3 MPa tensile stress as limit the occurrence of cracks in concrete. Sinapeul bridge abutment with integral system is still in the intact condition. Deflection of the bridge at the time of load test is 1.31 mm. But this time the bridge has decreased exceeded permission deflection (deflection occurred by 40 mm). Besides that, the slab also suffered destruction. One cause of the destruction of the bridge slab is the load factor. It is necessary for required effort to increase the capacity of the integral bridge with retrofitting. Retrofitting method also aims to restore the capacity of the bridge structure due to deterioration. Retrofitting can be done by shortening of the span or using Fibre Reinforced Polymer (FRC). Based on the results obtained by analysis of that method of retrofitting with Fibre Reinforced Polymer (FRC) is more simple and effective. Retrofitting with FRP can increase the capacity of the shear and bending moment becomes 41% of the existing bridge. Retrofitting with FRP method does not change the integral system on the bridge Sinapeul become conventional bridges.

  17. Implementation of a Refined Shear Rating Methodology for Prestressed Concrete Girder Bridges

    Science.gov (United States)

    2017-12-01

    Lower than desirable shear ratings at the ends of prestressed concrete beams have been the topic of ongoing research between MnDOT and the University of Minnesota. A recent study by the University of Minnesota entitled Investigation of Shear Distribu...

  18. Development of acoustic emission evaluation method for repaired prestressed concrete bridge girders.

    Science.gov (United States)

    2011-06-01

    Acoustic emission (AE) monitoring has proven to be a useful nondestructive testing tool in ordinary reinforced concrete beams. Over the past decade, however, the technique has also been used to test other concrete structures. It has been seen that ac...

  19. The Basic Differential Equations of Self-Anchored Cable-Stayed Suspension Bridge

    Directory of Open Access Journals (Sweden)

    Wang Hui-Li

    2010-01-01

    Full Text Available The static behavior of self-anchored cable-stayed suspension bridge under vertical load is described with the continuum method. Based on the partition generalized variation principle, considering the compression-bending coupling effect of the main girder and the tower, the large displacement incomplete generalized potential energy functional of three-span self-anchored cable-stayed suspension bridge is established. Then, the basic differential equations of self-anchored cable-stayed suspension bridge are derived through constraint variation. Taking a self-anchored cable-stayed suspension bridge with main span 100 m, for example, the results by the proposed analytic method agree with that of numerical analysis. Therefore, the basic differential equations proposed in this paper could be applied to the preliminary analysis of self-anchored cable-stayed suspension bridge. The equations also provide a theoretical basis to describe the static behavior of this type of bridge.

  20. Numerical analysis of heat-curved I-girders

    Directory of Open Access Journals (Sweden)

    Antoine Gergess

    2017-10-01

    Full Text Available Heat curving is a practical and economical process used by steel fabricators for curving structural steel. In this method, the flange edges of a fabricated straight girder are asymmetrically heated to induce residual curvature on cooling. Available analytical methods for predicting the resulting residual stress, strain and curvature are complex and iterative because of the need to account for material and geometric non-linearity. This paper presents a single-step, non-iterative, numerical procedure for determining the effects of heat-curving on residual stress and strain based on a previously developed simplified analysis. Thermal equilibrium equations for idealized heating profiles are first recast in a general parametric form and then solved numerically for standard heating width and temperature using modern technical computing. The resulting solutions are expressed as polynomial functions to allow the solution space for the residual curvature to be graphically represented. Curvature predictions using this simplified approach are shown to be within 11% of measured values and within 5% of values obtained using more rigorous numerical methods.

  1. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data......F) docking experiment against an existing technique, which requires the user to perform the rotation and scaling of the box explicitly. The precision of the users' box construction is evaluated by a novel error metric measuring the difference between two boxes. The results of the experiment strongly indicate...... that for precision docking of 9 DoF boxes, some of the proposed techniques are significantly better than ones with explicit rotation and scaling. Another interesting result is that the number of DoF simultaneously controlled by the user significantly influences the precision of the docking....

  2. Design proposal for ultimate shear strength of tapered steel plate girders

    Directory of Open Access Journals (Sweden)

    A. Bedynek

    2017-03-01

    Full Text Available Numerous experimental and numerical studies on prismatic plate girders subjected to shear can be found in the literature. However, the real structures are frequently designed as non-uniform structural elements. The main objective of the research is the development of a new proposal for the calculation of the ultimate shear resistance of tapered steel plate girders taking into account the specific behaviour of such members. A new mechanical model is presented in the paper and it is used to show the differences between the behaviour of uniform and tapered web panels subjected to shear. EN 1993-1-5 design specifications for the determination of the shear strength for rectangular plates are improved in order to assess the shear strength of tapered elements. Numerical studies carried out on tapered steel plate girders subjected to shear lead to confirm the suitability of the mechanical model and the proposed design expression.

  3. Finite elements sensitivity study in the buckling behaviours of corrugated web girder under shear load

    Science.gov (United States)

    De'nan, Fatimah; Hassan, Md Hadli Abu; Rahim, Mohd Asri Ab

    2017-10-01

    This paper presents a study on the ultimate load behaviour of corrugated girder webs under shear loading following nonlinear finite element analysis. Sensitivity analyses conducted herein are numbers of corrugation wave, elements density, initial imperfection and material nonlinearities. This paper aimed to investigate the influence of this sensitivity to the ultimate shear load, buckling and post-buckling behaviours of the corrugated web girder under shear loading condition. Two web thicknesses have been considered in the study, while flanges were designed to be strong enough to ensure the shear governed. The corrugated profiled geometry remained constant for all models. The ultimate shear loads were reported and compared with the existing theoretical design. Based on the numerical results, this sensitivity analysis does not have a major effect on ultimate shear load and post-buckling behaviours. However, when the girder is controlled by elastic buckling, the shear resistance is higher compared to the sear calculated according to the existing theoretical design.

  4. Structural analysis of a composite continuous girder with a single rectangular web opening

    Directory of Open Access Journals (Sweden)

    Mohamed A. ElShaer

    2017-08-01

    In this paper, a non-linear finite element analysis has been done to analyze the deflection in the steel section and internal stresses in the concrete slab for continuous composite girders with a single rectangular opening in the steel web. ANSYS computer program (version 15 has been used to analyze the three-dimensional model. The reliability of the model was demonstrated by comparison with experimental results of continuous composite beams without an opening in the steel web carried out by another author. The parametric analysis was executed to investigate the width, height, and position of the opening in one span on the behavior of a composite girder under vertical load. The results indicated that when the width of opening is less than 0.05 of length of a single span and the height is less than 0.15 of the steel web, the deflection and internal stresses increased less than 10% comparing to continuous composite girders without an opening.

  5. Wind Resistant Design of Bridges in Japan Developments and Practices

    CERN Document Server

    Fujino, Yozo; Tanaka, Hiroshi

    2012-01-01

    For long-span bridges, wind action is a dominant factor in their safety and serviceability. A large number of long-span bridges have been built in Japan over the past 30 years, and tremendous amounts of research and technical development have been accomplished in wind resistant design. This book is a compilation of the results of active research and development. Wind resistant design standards generated in Japan are described in the first few chapters. Then comes information such as design wind speed, structural damping, wind tunnel tests, and analyses, which provide the basis of the design standards. Wind-induced vibrations and their control of girders, towers, cables, and other features are explained with examples of field measurements. Comprehensive listings of Japanese experience in vibration control are also presented. Because achieving particularly dynamic safety against wind is still not an easy task, these data and information will be valuable assets for the wind-engineering and bridge-engineering com...

  6. Dynamic Analysis of Cable-Stayed Bridges Affected by Accidental Failure Mechanisms under Moving Loads

    Directory of Open Access Journals (Sweden)

    Fabrizio Greco

    2013-01-01

    Full Text Available The dynamic behavior of cable-stayed bridges subjected to moving loads and affected by an accidental failure in the cable suspension system is investigated. The main aim of the paper is to quantify, numerically, the dynamic amplification factors of typical kinematic and stress design variables, by means of a parametric study developed in terms of the structural characteristics of the bridge components. The bridge formulation is developed by using a geometric nonlinear formulation, in which the effects of local vibrations of the stays and of large displacements in the girder and the pylons are taken into account. Explicit time dependent damage laws, reproducing the failure mechanism in the cable system, are considered to investigate the influence of the failure mode characteristics on the dynamic bridge behavior. The analysis focuses attention on the influence of the inertial characteristics of the moving loads, by accounting coupling effects arising from the interaction between girder and moving system. Sensitivity analyses of typical design bridge variables are proposed. In particular, the effects produced by the moving system characteristics, the tower typologies, and the failure mode characteristics involved in the cable system are investigated by means of comparisons between damaged and undamaged bridge configurations.

  7. Impact Coefficient Analysis of Long-Span Railway Cable-Stayed Bridge Based on Coupled Vehicle-Bridge Vibration

    Directory of Open Access Journals (Sweden)

    Yongle Li

    2015-01-01

    Full Text Available Compared with medium and small span bridges, very limited attention has been paid on the research of the impact coefficient of long-span railway bridges. To estimate the impact effects of long-span railway bridges subjected to moving vehicles, a real long-span railway cable-stayed bridge is regarded as the research object in this study, and a coupled model of vehicle-bridge system is established. The track irregularities are taken as the system excitation and the dynamic responses of the vehicle-bridge system are calculated. The impact effects on main girder, stayed cable, bearings, and bridge tower are discussed at various vehicle speeds. The results show that different components of the long-span railway cable-stayed bridge have different impact coefficients. Even for each part, the impact coefficient is also different at different local positions. It reveals that the impact coefficients in the actual situation may have significant differences with the related code clauses in the present design codes.

  8. Deck forms for bridge construction safety.

    Science.gov (United States)

    2007-08-31

    Because I-girders have inherently weak torsion resistance, cross-frames and/or diaphragms are placed at close : spacing intervals to minimize the susceptibility of individual girders to instability during construction. A recent : increase in fatigue ...

  9. Math in the Box

    Science.gov (United States)

    DeYoung, Mary J.

    2009-01-01

    This article describes how to make an origami paper box and explores the algebra, geometry, and other mathematics that unfolds. A set of origami steps that transforms the paper into an open box can hold mathematical surprises for both students and teachers. An origami lesson can engage students in an open-ended exploration of the relationship…

  10. ALUMINUM BOX BUNDLING PRESS

    Directory of Open Access Journals (Sweden)

    Iosif DUMITRESCU

    2015-05-01

    Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

  11. Comportamiento estructural y criterios de diseño de los puentes extradosados: visión general y estado del arte Structural behavior and design criteria of extradosed bridges: general insight and state of the art

    Directory of Open Access Journals (Sweden)

    José Benjumea

    2010-01-01

    Full Text Available Durante los últimos 10 años, los puentes extradosados se han convertido en una solución estructural atractiva alrededor del mundo, gracias a los buenos resultados obtenidos con las primeras realizaciones en Japón. Esta nueva tipología, reconocida generalmente como una solución intermedia entre los puentes atirantados y los de pretensado de viga cajón construidos por voladizos sucesivos, se ha convertido en una opción interesante. Por consiguiente, dado el interés que hoy en día existe alrededor de este tipo de puente, en este trabajo se presenta el contexto histórico que describe su origen, y se exponen la influencia de los principales elementos estructurales en el comportamiento del puente, y los criterios de diseño que han sido propuestos por investigadores en el tema. De esta manera, se espera ofrecer una visión general de la concepción y el comportamiento estructural de los puentes extradosados para que sea considerada una alternativa más de tipología estructural de puentes en nuestro medio.Over the past 10 years, Extradosed bridges have become an attractive structural type around the world, due to the good results obtained with the first bridges constructed in Japan. This new typology, generally recognized as an intermediate solution between cable stayed bridges and cantilever constructed prestressed box-girder bridges, because these take advantages of design and constructions methods of the other two typologies, has become an interesting option. Therefore, given the interest that exist about this type of bridge, in this paper the historical context that describes its origin, the influence of the principal structural elements and the design criteria proposed by researchers are presented. In this way it is expected to offer a general insight into the design conception and structural behavior of Extradosed Bridges, so that they may be considered as an alternative structure for bridges in the Americas.

  12. Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System.

    Science.gov (United States)

    Kim, Sungkon; Lee, Jungwhee; Park, Min-Seok; Jo, Byung-Wan

    2009-01-01

    This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM) systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN) was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms.

  13. Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System

    Directory of Open Access Journals (Sweden)

    Min-Seok Park

    2009-10-01

    Full Text Available This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms.

  14. Multi-Scale Bridge Wash Out Simulation During Tsunami by Using a Particle Method

    Directory of Open Access Journals (Sweden)

    Miyagawa Yoshiya

    2016-01-01

    Full Text Available In 2011, the huge tsunami caused by the great east Japan earthquake devastated many infrastructures in pacific coast of north eastern Japan. Particularly, collapse of bridges caused a traffic disorder and these collapse behaviors led to delay of recovery after the disaster. In this study, the bridge wash away accident is selected as a target issue, and it is represented by a numerical simulation. For this purpose, Smoothed Particle Hydrodynamics (SPH Method, which is one of the pure mesh free methods, is utilized for the rigid body motion simulation. In this study, rigid body motion is introduced for the fluid-rigid interaction behavior during bridge wash away simulation. In the numerical analysis, the upper bridge structure is washed away by receiving an impact fluid force. The wash away simulation of two types of the bridge girder showed good agreement with the real accident on the great east Japan earthquake tsunami.

  15. Design of pedestrian truss bridge with Sengon-Rubber laminated veneer lumber

    Science.gov (United States)

    Herbudiman, B.; Pranata, Y. A.; Pangestu, L.

    2017-12-01

    Timber bridges are one of the bridge that has long been used, but nowadays, large dimension of sawn timber has limited supply and also it is not environmental-friendly. Laminated veneer lumber (LVL) is a engineered wood that becomes one of the promising alternative, because it is made from lower quality wood that processed to be used as a more quality one. The bridge planned to be a pedestrian truss bridge with length of 9 m, width of 3 m, height of 2.5 m, and using bolt and steel plate as its connection system. Mechanical properties of LVL obtained directly from laboratory test result. Bridge modeling and planning for wood construction refers to SNI 7973:2013, while the loading refers to SNI 1725:2016. Based on the modelling and calculation, the dimension of truss frame and girder beam which are 9 cm x 9 cm and 9 cm x 18 cm have adequate strengths and satisfy deflection requirement.

  16. Transverse Sub-Assemblage Testing of the Inverted-T Bridge System

    OpenAIRE

    Mercer, Matthew Sherman

    2012-01-01

    The inverted-T bridge system is a rapid bridge construction technique that consists of precast inverted-T girders placed adjacent to one another and covered with a cast-in-place deck. This system was first implemented in the U.S. by the Minnesota Department of Transportation (Mn/DOT). This research focuses on improving the constructability of the Mn/DOT system while maintaining the systemâ s structural performance characteristics. To accomplish this goal, five sub-assemblage specimens were ...

  17. Damage identification in highway bridges using distribution factors

    Science.gov (United States)

    Gangone, Michael V.; Whelan, Matthew J.

    2017-04-01

    The U.S. infrastructure system is well behind the needs of the 21st century and in dire need of improvements. The American Society of Civil Engineers (ASCE) graded America's Infrastructure as a "D+" in its recent 2013 Report Card. Bridges are a major component of the infrastructure system and were awarded a "C+". Nearly 25 percent of the nation's bridges are categorized as deficient by the Federal Highway Administration (FWHA). Most bridges were designed with an expected service life of roughly 50 years and today the average age of a bridge is 42 years. Finding alternative methods of condition assessment which captures the true performance of the bridge is of high importance. This paper discusses the monitoring of two multi-girder/stringer bridges at different ages of service life. Normal strain measurements were used to calculate the load distribution factor at the midspan of the bridge under controlled loading conditions. Controlled progressive damage was implemented to one of the superstructures to determine if the damage could be detected using the distribution factor. An uncertainty analysis, based on the accuracy and precision of the normal strain measurement, was undertaken to determine how effective it is to use the distribution factor measurement as a damage indicator. The analysis indicates that this load testing parameter may be an effective measure for detecting damage.

  18. Chaos theory analysis of a cable-stayed bridge: Part I. Finite element model development

    Science.gov (United States)

    Jin, Shuang; Livingston, Richard A.

    2007-04-01

    Cable-stayed bridges can exhibit large amplitude irregular stay cable oscillations under certain conditions of combined traffic flow and rain-wind loads that can pose severe risks to structural integrity. To investigate the mechanisms causing this behavior, a high fidelity nonlinear finite element model of a typical cable-stayed bridge has been developed using LS-DYNA based on the design of the Bill Emerson Memorial Bridge at Cape Girardeau, MO. The model uses over 540,000 finite elements representing 1254 bridge components to fully describe the detailed real geometry of the bridge tower, deck, stay cables, edge girders and floor-beam support girders. Traffic loads on the bridge deck are simulated by a Poisson Distributed Pulse (PDP) stochastic process model involving multi-lane traffic flows of more than 300 vehicles of various axle loads with varying arrival rates. The response data sets generated by the LS-DYNA simulations were then analyzed for chaotic behavior with the software CTBR. This extracts the nonlinear system invariants, the Lyapunov exponents, to identify the chaotic behavior from the dynamics of the structural system. The simulations showed positive Lyapunov exponents at various locations of the bridge deck and the bridge stay cable network. The analysis of these results revealed that even in the absence of strong rain-wind excitations the bridge deck vibration exhibits significant chaotic behavior that could excite the stay cables into a stronger chaotic regime, especially at the upper portion of the networked stay cables. This illustrates a phenomenon often ignored or unable to be captured by conventional linear dynamics analysis. Analysis of actual data sets collected from a monitoring network on the bridge also confirmed this chaotic behavior.

  19. Field Testing and Load Rating Report for Bridge No. 4, Hybrid Composite Beam Span, at Fort Knox, Kentucky

    Science.gov (United States)

    2016-09-01

    consists of two simply supported spans. One span is comprised of five rolled steel girders supporting a non-composite reinforced concrete slab . The...load configuration. Additionally, a controlling MLC vehicle classification was determined for the bridge for both tracked and wheeled configurations...span. The MLC values for tracked and wheeled vehicles were based on AASHTO Operating Load Factors. A tracked MLC of 139 tons was obtained from an

  20. 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.

  1. Preliminary investigation of steel girder end panel shear resistance.

    Science.gov (United States)

    2010-01-01

    Prior to 1973, steel bridges in California were designed based on Allowable Stress : Design and the shear design of web and transverse stiffeners was based on the : average shear stress in the web. The tension field action equation similar to the : c...

  2. Structure and biochemical function of a prototypical Arabidopsis U-box domain

    DEFF Research Database (Denmark)

    Andersen, Pernille; Kragelund, Birthe B; Olsen, Addie N

    2004-01-01

    19p U-box and RING finger domains. In these proteins, conserved hydrophobic residues form a putative E2-binding cleft. By contrast, they contain no common polar E2 binding site motif. Two hydrophobic cores stabilize the AtPUB14 U-box fold, and hydrogen bonds and salt bridges interconnect the residues...

  3. BoxPlot++

    OpenAIRE

    Azmeh, Zeina; Hamoui, Fady; Huchard, Marianne

    2011-01-01

    We propose the BoxPlot++ as an extension of Tukey's boxplot. We improve the resulting data values distribution by removing the repeated values and by calculating distances between the points and the nearest median.

  4. Boxes and Shelves

    OpenAIRE

    Hughes, Dean

    2008-01-01

    The Boxes and Shelves series from 2008 are are all made from the backing card from discarded writing pads. Boxes and Shelves extended my investigation of quotidian materials and their relationship to the origins of creative toil. Since 1996 my research has sought to identify and locate instances where the 'unmeasurable' meets the measurable. I have consistently employed a range of utilitarian materials such as bus seats, bus tickets, puddles, A4 writing paper, to present a series of 'problem ...

  5. Freedom to box.

    Science.gov (United States)

    Warburton, N

    1998-02-01

    The british Medical Association wants to criminalise all boxing. This article examines the logic of the arguments it uses and finds them wanting. The move from medical evidence about the risk of brain damage to the conclusion that boxing should be banned is not warranted. The BMA's arguments are a combination of inconsistent paternalism and legal moralism. Consistent application of the principles implicit in the BMA's arguments would lead to absurd consequences and to severe limitations being put on individual freedom.

  6. Dynamic characterization and damage detection in the I-40 bridge over the Rio Grande

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, C.R.; Baker, W.E.; Bell, T.M.; Cone, K.M.; Darling, T.W.; Duffey, T.A.; Eklund, A.; Migliori, A.

    1994-06-01

    In the 1960`s and 1970`s over 2500 bridges were built in the U.S. with a design similar to those on Interstate 40 over the Rio Grande in Albuquerque, New Mexico. These bridges were built without structural redundancy and typically have only two plate girders carrying the entire dead and live loads. Failure of either girder is assumed to produce catastrophic failure of the bridge, hence these bridges are referred to as fracture-critical bridges. The Federal Highway Administration (FHWA) and the National Science Foundation (NSF) have provided funds to New Mexico State University (NMSU) through the New Mexico State Highway and Transportation Department (NMSH&TD) and The Alliance For Transportation Research (ATR) for evaluation and testing of the existing fracture critical bridges over the Rio Grande. Because the 1-40 bridges over the Rio Grande were to be razed during the summer of 1993, the investigators were able to introduce simulated fatigue cracks, similar to those observed in the field, into the structure in order to test various damage identification methods and to observe the changes in load paths through the structure caused by the cracking. To support this research effort, NMSU contracted Los Alamos National Laboratory (LANL) to perform experimental modal analyses, and to develop experimentally verified numerical models of the bridge. Scientists from the LANL`s Condensed Matter and Thermal Physics Group (P-10) applied state-of-the-art sensors and data acquisition software to the modal tests. Engineers from the LANL`s Advanced Engineering Technology Group (MEE-13) conducted ambient and forced vibration tests to verify detailed and simplified finite element models of the bridge. Forced vibration testing was done in conjunction with engineers from Sandia National Laboratory (SNL) who provided and operated a hydraulic shaker.

  7. Finite element analysis of deep wide-flanged pre-stressed girders to understand and control end cracking : [work plan].

    Science.gov (United States)

    2011-01-01

    Project -- Work Approach: The first phase will examine the critical problem of controlling cracking in the 82W : girders. This complex problem is controlled by effects of concentrated stresses, force : transfer from pre-tensioning strand, inelastic b...

  8. Environmental Durability of Reinforced Concrete Deck Girders Strengthened for Shear with Surface-Bonded Carbon Fiber-Reinforced Polymer

    Science.gov (United States)

    2009-05-01

    "This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort...

  9. Environmental durability of reinforced concrete deck girders strengthened for shear with surface bonded carbon fiber-reinforced polymer : final report.

    Science.gov (United States)

    2009-05-01

    This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced : concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effor...

  10. Cable Tester Box

    Science.gov (United States)

    Lee, Jason H.

    2011-01-01

    Cables are very important electrical devices that carry power and signals across multiple instruments. Any fault in a cable can easily result in a catastrophic outcome. Therefore, verifying that all cables are built to spec is a very important part of Electrical Integration Procedures. Currently, there are two methods used in lab for verifying cable connectivity. (1) Using a Break-Out Box and an ohmmeter this method is time-consuming but effective for custom cables and (2) Commercial Automated Cable Tester Boxes this method is fast, but to test custom cables often requires pre-programmed configuration files, and cables used on spacecraft are often uniquely designed for specific purposes. The idea is to develop a semi-automatic continuity tester that reduces human effort in cable testing, speeds up the electrical integration process, and ensures system safety. The JPL-Cable Tester Box is developed to check every single possible electrical connection in a cable in parallel. This system indicates connectivity through LED (light emitting diode) circuits. Users can choose to test any pin/shell (test node) with a single push of a button, and any other nodes that are shorted to the test node, even if they are in the same connector, will light up with the test node. The JPL-Cable Tester Boxes offers the following advantages: 1. Easy to use: The architecture is simple enough that it only takes 5 minutes for anyone to learn how operate the Cable Tester Box. No pre-programming and calibration are required, since this box only checks continuity. 2. Fast: The cable tester box checks all the possible electrical connections in parallel at a push of a button. If a cable normally takes half an hour to test, using the Cable Tester Box will improve the speed to as little as 60 seconds to complete. 3. Versatile: Multiple cable tester boxes can be used together. As long as all the boxes share the same electrical potential, any number of connectors can be tested together.

  11. Evaluation and analysis of decked bulb T beam bridges.

    Science.gov (United States)

    2015-03-01

    A new corrosion-free decked bulb T beam bridge system has been developed to overcome some of the problems : associated with the construction of side-by-side box beam bridges such as the lack of inspection space between : beams and the longitudinal de...

  12. Double-composite rectangular truss bridge and its joint analysis

    Directory of Open Access Journals (Sweden)

    Yongjian Liu

    2015-08-01

    Full Text Available This paper describes a novel composite tubular truss bridge with concrete slab and concrete-filled rectangular chords. With concrete slab plus truss system and joints reinforced with concrete and Perfobond Leiste rib, double composite truss bridge proved to be a fairly suitable solution in negative moment area. Perfobond Leiste shear connector (PBL is widely implemented in the composite structure for its outstanding fatigue resistance. In this pilot bridge, Perfobond Leister ribs (PBR were installed in the truss girder's joints, which played double roles as shear connector and stiffener. An erection method and overall bridge structural analysis were then presented. Typical joints in the pilot bridge were selected to analyze the effect of PBR. Investigation of the effect of PBR in concrete-filled tubular joints was elaborated. Comparison has revealed that concrete-filled tubular joints with PBR have much higher constraint capability than joints without PBR. For rectangular tubular truss, the punching shear force of the concrete filled joint with PBR is approximately 43% larger than that of the joint without PBR. Fatigue performance of the joint installed with PBR was improved, which was found through analysis of the stress concentration factor of joint. The PBR installed in the joints mitigated the stress concentration factor in the chord face. Therefore, the advantages of this new type of bridge are demonstrated, including the convenience of construction using rectangular truss, innovative concept of structural design and better global and local performances.

  13. Fabrication and erection of 'Chuo ohashi bridge' for Tokyo Metropolitan Government. Tokyoto kensetsukyoku 'Chuo ohashi' no seisaku oyobi kasetsu

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The present report outlines the superstructure of 'Chuo Ohashi Bridge' spanning the Sumida River, Tokyo Metropolis. Being 210.7m in length and 25.0m in breadth, that bridge is a cable-stayed bridge partially curved with a 220m radius curvature. Having a height of 76.8m, its main tower is shaped into an upside-down V with a curved top. Description of the points of which care was specially taken for the fabrication and construction in yard covers the cable anchorage of both girders and tower, assembly and welding, anti-shrinkage camber of girders, weld bevel preparation for the tower, tentative assembly, and accuracy control. Results of the wind tunnel test with a (1/50) scale model are as follows: stay cables were installed as measures against the vibration during the main tower erection. The main girders, main tower and cables were the order of superstructural erection. The cable tensioning was supervised mainly with its proper tension adjustment and subsidiarily for the configuration of bridge built. 2 refs., 10 figs., 1 tab.

  14. Discrete vortex method simulations of aerodynamic admittance in bridge aerodynamics

    DEFF Research Database (Denmark)

    Rasmussen, Johannes Tophøj; Hejlesen, Mads Mølholm; Larsen, Allan

    , and to determine aerodynamic forces and the corresponding flutter limit. A simulation of the three-dimensional bridge responseto turbulent wind is carried out by quasi steady theory by modelling the bridge girder as a line like structure [2], applying the aerodynamic load coefficients found from the current version...... of DVMFLOW in a strip wise fashion. Neglecting the aerodynamic admittance, i.e. the correlation of the instantaneous lift force to the turbulent fluctuations in the vertical velocities, leads to higher response to high frequency atmospheric turbulence than would be obtained from wind tunnel tests...... velocity spectra are found in good agreement with the target spectra. The aerodynamic admittance of the structure is measured by sampling vertical velocities immediately upstream of the structure and the lift forces on the structure. The method is validated against the analytic solution for the admittance...

  15. 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.

  16. APPLICATION OF ULTRA-HIGH PERFORMANCE CONCRETE TO PEDESTRIAN CABLE-STAYED BRIDGES

    Directory of Open Access Journals (Sweden)

    CHI-DONG LEE

    2013-06-01

    Full Text Available The use of ultra-high performance concrete (UHPC, which enables reducing the cross sectional dimension of the structures due to its high strength, is expected in the construction of the super-long span bridges. Unlike conventional concrete, UHPC experiences less variation of material properties such as creep and drying shrinkage and can reduce uncertainties in predicting time-dependent behavior over the long term. This study describes UHPC’s material characteristics and benefits when applied to super-long span bridges. A UHPC girder pedestrian cable-stayed bridge was designed and successfully constructed. The UHPC reduced the deflections in both the short and long term. The cost analysis demonstrates a highly competitive price for UHPC. This study indicates that UHPC has a strong potential for application in the super-long span bridges.

  17. AHP-VIKOR Bridge Structural System Selection in Urban Areas Tehran: Interchanges Case Study

    Directory of Open Access Journals (Sweden)

    Ali Akbar Ramezanianpour

    2016-10-01

    Full Text Available The selection of “Structural system” is one of the most important factors in any bridge and infrastructure design. Designers perform the structural calculations for the project determines the priorities as well as design and performance criteria. Further analysis of the structural selection problem and the identification of the bridge desirable capabilities, triggered the consideration of analytic hierarchy process (AHP as a possible basis for the decision making. The methodology uses the VIKOR to evaluate the alternatives according to the decision criteria and determine the solution. The methodology was developed by a group of bridge designers involved in design and management of urban infrastructure projects and demonstrated using a Steel Girder bridge in an urban area as an optimum alternative.

  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....

  19. The BOXES Methodology Black Box Dynamic Control

    CERN Document Server

    Russell, David W

    2012-01-01

    Robust control mechanisms customarily require knowledge of the system’s describing equations which may be of the high order differential type.  In order to produce these equations, mathematical models can often be derived and correlated with measured dynamic behavior.  There are two flaws in this approach one is the level of inexactness introduced by linearizations and the other when no model is apparent.  Several years ago a new genre of control systems came to light that are much less dependent on differential models such as fuzzy logic and genetic algorithms. Both of these soft computing solutions require quite considerable a priori system knowledge to create a control scheme and sometimes complicated training program before they can be implemented in a real world dynamic system. Michie and Chambers’ BOXES methodology created a black box system that was designed to control a mechanically unstable system with very little a priori system knowledge, linearization or approximation.  All the method need...

  20. Experimental study on AR fiberglass connectors for bridges made of composite materials

    Directory of Open Access Journals (Sweden)

    Tolosana, N.

    2006-06-01

    Full Text Available One highly relevant aspect in composite material bridgedesing is the study of the shear connectors to be used.Composite material bridges most commonly comprise acomposite deck resting on steel or reinforced concrete girders.This article analyzes the connectors most frequentlyused in such bridges.It also reviews the connectors used in the King StormwaterChannel Bridge, whose fibreglass deck is supported bygirders made of concrete-filled carbon fibre girders.The paper advances proposals for several types of connectorsand discusses the results of push-out test run ona number of prototypes with different geometries.The results are analyzed to identify the optimum model forthe “Autovia del Cantabrico” Overpass, with its 46-m span,carbon fibre girders and AR glass shear connectors.Un aspecto relevante dentro del proyecto de un puenterealizado en materiales compuestos es el estudio de losconectores. El caso mas frecuente de puente en materialescompuestos es aquel que presenta un tablero de materialescompuestos soportado por vigas metalicas o de hormigonarmado. En este trabajo se analizaran los tipos deconectores mas utilizados en este tipo de puentesSe analizaran tambien los conectores utilizados en elKing Stormwater Channel Bridge, donde ademas deltablero en fibra de vidrio, se fabricaron las vigas en fibrasde carbono rellenas de hormigon.En este articulo se propondran varios tipos de conectoresy se presentaran los resultados experimentales correspondientesal ensayo de “push-out” de varios prototipos condiferentes geometrias.Tras evaluar los resultados, se determinara el mas idoneopara su implantacion en el Paso Superior de la Autovia delCantabrico, de 46 metros de luz y que presenta las vigasen fibra de carbono y los conectores de vidrio AR.

  1. Opto-Box

    CERN Document Server

    Bertsche, David; The ATLAS collaboration; Welch, Steven; Smith, Dale Shane; Che, Siinn; Gan, K.K.; Boyd, George Russell Jr

    2015-01-01

    The opto-box is a custom mini-crate for housing optical modules, which process and transfer optoelectronic data. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35x10x8 cm^3. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits (ASICs), were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain.

  2. Estimation of Tendon Force Distribution in Prestressed Concrete Girders Using Smart Strand

    Directory of Open Access Journals (Sweden)

    Keunhee Cho

    2017-12-01

    Full Text Available The recently developed smart strand offers the possibility of measuring the prestress force of the tendon from jacking and all along its service life. In the present study, a method estimating the force distribution in all the tendons of a prestressed concrete (PSC girder installed with one smart strand is proposed. The force distribution in the prestressed tendons is formulated by the friction and the anchorage slip, and is obtained through an optimization process with respect to the compatibility conditions and equilibrium of the forces in the section of the PSC girder. The validation of the proposed method through a numerical example and experiment shows that it can be used to estimate the force developed in the tendon.

  3. Numerical Simulation of Vertical Random Vibration of Train-Slab Track-Bridge Interaction System by PEM

    OpenAIRE

    Zhi-ping Zeng; Zhi-wu Yu; Yan-gang Zhao; Wen-tao Xu; Ling-kun Chen; Ping Lou

    2014-01-01

    The paper describes the numerical simulation of the vertical random vibration of train-slab track-bridge interaction system by means of finite element method and pseudoexcitation method. Each vehicle is modeled as four-wheelset mass-spring-damper system with two-layer suspension systems. The rail, slab, and bridge girder are modeled by three-layer elastic Bernoulli-Euler beams connected with each other by spring and damper elements. The equations of motion for the entire system are derived ac...

  4. Maintained ship hull girder ultimate strength reliability considering corrosion and fatigue

    DEFF Research Database (Denmark)

    Hu, Yong; Cui, W.; Pedersen, Preben Terndrup

    2004-01-01

    The prupose of this paper is to propose a methodology to assess the time-variant ultimate strength of ship hull girder under the degradations of corrosion and fatigue. The effects of fatigue cracks on the tensile and compressive residual ultimate strength of stiffened panels and unstiffened plates...... developed is illustrated by application to a tanker. For a given set of inspection and repair criteria, the ultimate bending moment and reliability as a function of ship age is predicted....

  5. Teaching with Box Tops.

    Science.gov (United States)

    Raiser, Lynne; D'Zamko, Mary Elizabeth

    1984-01-01

    Using environmental materials (such as the phone book and placemats from fast food restaurants) can be a motivating way to teach learning disabled students skills and concepts, as shown in an approach to reading, math, science and nutrition, and social studies instruction using a JELL-O brand gelatin box. (CL)

  6. Many-box locality

    Science.gov (United States)

    Zhou, Yuqian; Cai, Yu; Bancal, Jean-Daniel; Gao, Fei; Scarani, Valerio

    2017-11-01

    There is an ongoing search for a physical or operational definition for quantum mechanics. Several informational principles have been proposed which are satisfied by a theory less restrictive than quantum mechanics. Here, we introduce the principle of "many-box locality," which is a refined version of the previously proposed "macroscopic locality." These principles are based on coarse graining the statistics of several copies of a given box. The set of behaviors satisfying many-box locality for N boxes is denoted LNM B. We study these sets in the bipartite scenario with two binary measurements, in relation with the sets Q and Q1 +A B of quantum and "almost quantum" correlations, respectively. We find that the LNM B sets are, in general, not convex. For unbiased marginals, by working in the Fourier space we can prove analytically that LNM B⊈Q for any finite N , while L∞M B=Q . Then, with suitably developed numerical tools, we find an example of a point that belongs to L16M B but not to Q1 +A B. Among the problems that remain open is whether Q ⊂L∞M B .

  7. IN-A-BOX

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 2. Claude Elwood Shannon. Priti Shankar. Article-in-a-Box Volume 7 Issue 2 February 2002 pp 2-3. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/007/02/0002-0003. Author Affiliations.

  8. Mystery Box Marvels

    Science.gov (United States)

    Santos, Joel; Centurio, Tina

    2012-01-01

    What happens in the first week of school could very well set the stage for the rest of the school year. Setting high standards for science activities based in inquiry can start on the first day of science class and develop as the year unfolds. With the use of simple, readily available, inexpensive materials, an efficient mystery box lesson can be…

  9. Operant-Box Sociology

    Science.gov (United States)

    Dimond, Stuart J.

    1971-01-01

    Sketches a model which considers society a teacher which instructs like an operant box..." The author contends that the family, the school, the play group, the adolescent gang, the office, the prison, the mental hospital, each reward, instruct and control the individual who learns by operant means what the institution teaches." (Author/AL)

  10. Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

    Directory of Open Access Journals (Sweden)

    Jungwon Huh

    2015-01-01

    Full Text Available The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

  11. 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,...

  12. A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

    Science.gov (United States)

    Asgari, B; Osman, S A; Adnan, A

    2014-01-01

    Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  13. A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

    Directory of Open Access Journals (Sweden)

    B. Asgari

    2014-01-01

    Full Text Available Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM. The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

  14. Exciting test of a floating type cable stayed bridge and its response observation under the typhoon; Furotiingu keishiki shachokyo (Utagenkabashi) no kishinki shiken to taifuji oto kansoku

    Energy Technology Data Exchange (ETDEWEB)

    Uno, K. [Kyushu Kyoritsu Univ., Kitakyushu (Japan). Faculty of Engineering; Aso, T. [Yamaguchi Univ., Ube (Japan). Faculty of Engineering; Kitagawa, S. [Kyushu International Univ., Kitakyushu (Japan). Faculty of Economy; Kabashima, S.

    1995-09-20

    Recently, in case of the planning and designing of bridges, of course its practicality and execution stability are considered, but consideration for landscape also is a large problem. In particular, the selection of the bridge type is very important in order to protect the beautiful natural landscape. The cable stayed bridge has become to be executed often, owing to its elegant style, however, it becomes important theme clarify the antiseismic and wind stability because of its complicated structure system and very slender girder. In this paper, the results of the dynamic characteristics of a floating type cable stayed bridge (length 292.1 m and width 14.9 m) and the observation of its dynamic behavior under the typhoon are reported. Microtremor measurement was performed to determine the dynamic characteristics of the bridge under construction. After the construction of the bridge, the excitation test was carried out in order to confirm its natural frequencies, vibration modes and damping constants. From the results of the observation of the dynamic behavior of the girder and cables under the typhoon, the wind stability of this bridge was confirmed. 10 refs., 13 figs., 9 tabs.

  15. Rotational Angle Measurement of Bridge Support Using Image Processing Techniques

    Directory of Open Access Journals (Sweden)

    Young-Soo Park

    2016-01-01

    Full Text Available Measuring a very small rotational angle accurately and dynamically is indeed a challenging issue, especially in the case of bridge support. Also, existing inclinometers do not have sufficient resolution and accuracy to measure a bridge’s rotational angle. In this study, a new measurement system was developed to provide a practical means for measuring dynamic rotational angle of a bridge support. It features high resolution and accuracy compared with the available systems on the market. By the combinational use of a laser pointer and a vision-based displacement measurement system, the measurement accuracy was significantly increased. The accuracy and applicability were investigated through laboratory tests. From the laboratory tests, it has been found that the developed system can be applicable to bridge support with very small rotational angle. The effectiveness of the developed system was verified through field tests on real bridges. From the full-scale implementation on two PSC girder bridges, it is observed that the proposed system can measure the rotational angle with a high accuracy and reliability.

  16. Proposal of self-anchored cable-supported bridge with main span length of 500m; Chuo span 500m kibo no jiteishiki tsurigatashiki kyoryo ni kansuru teian

    Energy Technology Data Exchange (ETDEWEB)

    Fukasawa, Y.; Sugiyama, T. [Yamaguchi University, Yamaguchi (Japan). Faculty of Engineering; Kaneko, S.; Mukoyama, T.; Iwaki, T. [Pacific Consultants K.K., Tokyo (Japan)

    1995-12-15

    In order to investigate the feasibility of construction of cable-supported bridge at the site where ground condition is poor and/or air route restriction shoed be considered the static and dynamic characteristics of both self-anchored cable-stayed bridge with relatively low tower and self-anchored suspension bridge have been discussed. The main span length of bridge considered here is about 500 m because of the fact that stress resultant of main girder caused by design loads is considerably lower than its design strength in the existing cable-supported bridges of this scale. The result shows that the application of both types of cable-supported bridges to the above described site may be possible as enough static safety and economy are ensured. It has been also revealed that no problem may occur from both wind and earthquake resistant viewpoints. 10 refs., 24 figs., 8 tabs.

  17. The Effect of Deck Width Addition Toward Stability of Cable Stayed Bridge: Case Study of Siak Sri Indrapura Bridge, Riau

    Directory of Open Access Journals (Sweden)

    Supriyadi Bambang

    2017-01-01

    Full Text Available An aeroelastic interaction always take places in long-span bridge, i.e. the dynamic relationship between wind forces (aerodynamic and bridge structural motion (dynamics. Wind forces may lead to serviceability and safety problems, and may even cause instability of the whole bridge structure due to the flexibility nature of long span bridge structures.The slimer girder plate will make the structure more unstable as can be seen from the occurrence of lateral deformation. This paper presents the results analysis of cable stayed bridge that has total span of 640 m, two planes configuration of harp-typed hanger cable, the A shape pylons span along 320 m (main span,and side span of 160m. Structural analysis was conducted to determine the optimum ratio between width and spans of cable stayed bridge. The bridge was modeled with various width of 7 to 22 m. Structural modelling was conducted using SAP2000 software to analyze the structural stability of cable stayed bridge under wind load at speed of 35 m/s.The influence of wind loads to the cable stayed bridge stability can be seen based on the bridge deck deformation at the Y-axis (U2, in which for the width of the bridge deck of 7 m, 8 m, 9 m and 10 m, the deformation of U2 are 0.26 m; 0.17 m; 0.12 m and 0.10 m, respectively. Meanwhile, for bridge’s width of 11-22 m, the value of U2 axis deformation is relatively constant between 0.08 m to 0.07 m. This finding suggests that the ratio between width and length of bridge greatly affect the stability of the cable stayed bridge. Cable-stayed bridge, especially for concrete bridge, with two plain system having optimum ratio of width and length show no sign of an aerodynamic instability when fulfills the requirements of B ≥ L / 3.

  18. Hermit Points on a Box

    Science.gov (United States)

    Hess, Richard; Grinstead, Charles; Grindstead, Marshall; Bergstrand, Deborah

    2008-01-01

    Suppose that we are given a rectangular box in 3-space. Given any two points on the surface of this box, we can define the surface distance between them to be the length of the shortest path between them on the surface of the box. This paper determines the pairs of points of maximum surface distance for all boxes. It is often the case that these…

  19. 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...

  20. Opto-Box

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00377159; The ATLAS collaboration

    2015-01-01

    The opto-box is a custom mini-crate for housing optical modules, which process and transfer optoelectronic data. Many novel solutions were developed for the custom design and manufacturing. The system tightly integrates electrical, mechanical, and thermal functionality into a small package of size 35x10x8 cm$^{3}$. Special attention was given to ensure proper shielding, grounding, cooling, high reliability, and environmental tolerance. The custom modules, which incorporate Application Specific Integrated Circuits (ASICs), were developed through a cycle of rigorous testing and redesign. In total, fourteen opto-boxes have been installed and loaded with modules on the ATLAS detector. They are currently in operation as part of the LHC run 2 data read-out chain.

  1. Design of a Maglev Vibration Test Platform for the Research of Maglev Vehicle-girder Coupled Vibration Problem

    Directory of Open Access Journals (Sweden)

    Zhou Danfeng

    2017-01-01

    Full Text Available The maglev vehicle-girder coupled vibration problem has been encountered in many maglev test or commercial lines, which significantly degrade the performance of the maglev train. In previous research on the principle of the coupled vibration problem, it has been discovered that the fundamental model of the maglev girder can be simplified as a series of mass-spring resonators of different but related resonance frequencies, and that the stability of the vehicle-girder coupled system can be investigated by separately examining the stability of each mass-spring resonator – electromagnet coupled system. Based on this conclusion, a maglev test platform, which includes a single electromagnetic suspension control system, is built for experimental study of the coupled vibration problem. The guideway of the test platform is supported by a number of springs so as to change its flexibility. The mass of the guideway can also be changed by adjusting extra weights attached to it. By changing the flexibility and mass of the guideway, the rules of the maglev vehicle-girder coupled vibration problem are to be examined through experiments, and related theory on the vehicle-girder self-excited vibration proposed in previous research is also testified.

  2. Boxed Permutation Pattern Matching

    DEFF Research Database (Denmark)

    Amit, Mika; Bille, Philip; Cording, Patrick Hagge

    2016-01-01

    the goal is to only find the boxed subsequences of T that are order-isomorphic to P. This problem was introduced by Bruner and Lackner who showed that it can be solved in O(n3) time. Cho et al. [CPM 2015] gave an O(n2m) time algorithm and improved it to O(n2 logm). In this paper we present a solution...

  3. 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.

  4. A numerical study on the structural integrity of self-anchored cable-stayed suspension bridges

    Directory of Open Access Journals (Sweden)

    Paolo Lonetti

    2016-10-01

    Full Text Available A generalized numerical model for predicting the structural integrity of self-anchored cable-stayed suspension bridges considering both geometric and material nonlinearities is proposed. The bridge is modeled by means of a 3D finite element approach based on a refined displacement-type finite element approximation, in which geometrical nonlinearities are assumed in all components of the structure. Moreover, nonlinearities produced by inelastic material and second order effects in the displacements are considered for girder and pylon elements, which combine gradual yielding theory with CRC tangent modulus concept. In addition, for the elements of the suspension system, i.e. stays, hangers and main cable, a finite plasticity theory is adopted to fully evaluate both geometric and material nonlinearities. In this framework, the influence of geometric and material nonlinearities on the collapse bridge behavior is investigated, by means of a comparative study, which identifies the effects produced on the ultimate bridge behavior of several sources of bridge nonlinearities involved in the bridge components. Results are developed with the purpose to evaluate numerically the influence of the material and geometric characteristics of self-anchored cable-stayed suspension bridges with respect also to conventional bridge based on cablestayed or suspension schemes

  5. Assessment on transient sound radiation of a vibrating steel bridge due to traffic loading

    Science.gov (United States)

    Zhang, He; Xie, Xu; Jiang, Jiqing; Yamashita, Mikio

    2015-02-01

    Structure-borne noise induced by vehicle-bridge coupling vibration is harmful to human health and living environment. Investigating the sound pressure level and the radiation mechanism of structure-borne noise is of great significance for the assessment of environmental noise pollution and noise control. In this paper, the transient noise induced by vehicle-bridge coupling vibration is investigated by employing the hybrid finite element method (FEM) and boundary element method (BEM). The effect of local vibration of the bridge deck is taken into account and the sound responses of the structure-borne noise in time domain is obtained. The precision of the proposed method is validated by comparing numerical results to the on-site measurements of a steel girder-plate bridge in service. It implies that the sound pressure level and its distribution in both time and frequency domains may be predicted by the hybrid approach of FEM-BEM with satisfactory accuracy. Numerical results indicate that the vibrating steel bridge radiates high-level noise because of its extreme flexibility and large surface area for sound radiation. The impact effects of the vehicle on the sound pressure when leaving the bridge are observed. The shape of the contour lines in the area around the bridge deck could be explained by the mode shapes of the bridge. The moving speed of the vehicle only affects the sound pressure components with frequencies lower than 10 Hz.

  6. Bridge Failure Due to Inadequate Design of Bed Protection

    Science.gov (United States)

    Gupta, Yogita; Kaur, Suneet; Dindorkar, Nitin

    2017-12-01

    The shallow foundation is generally provided on non-erodible strata or where scour depth is less. It is also preferable for low perennial flow or standing water condition. In the present case study shallow foundation is adopted for box type bridge. The total length of the bridge is 132.98 m, consisting of eight unit of RCC box. Each unit is composed of three cell box. The bottom slab of box unit is acted as raft foundation, founded 500 mm below ground level. River bed protection work is provided on both upstream and downstream side along the whole length of the bridge as it is founded above scour level. The bridge collapsed during the monsoon just after two years of service. The present paper explains the cause of failure. This study on failure of the bridge illustrates the importance of bridge inspection before and after monsoon period and importance of the timely maintenance. Standard specifications of Indian Road Congress for the river bed protection work are also included.

  7. Damage Detection for Continuous Bridge Based on Static-Dynamic Condensation and Extended Kalman Filtering

    Directory of Open Access Journals (Sweden)

    Haoxiang He

    2014-01-01

    Full Text Available As an effective and classical method about physical parameter identification, extended Kalman filtering (EKF algorithm is widely used in structural damage identification, but the equations and solutions for the structure with bending deformation are not established based on EKF. The degrees of freedom about rotation can be eliminated by the static condensation method, and the dynamic condensation method considering Rayleigh damping is proposed in order to establish the equivalent and simplified modal based on complex finite element model such as continuous girder bridge. According to the requirement of bridge inspection and health monitoring, the online and convenient damage detection method based on EKF is presented. The impact excitation can be generated only on one location by one hammer actuator, and the signal in free vibration is analyzed. The deficiency that the complex excitation information is needed based on the traditional method is overcome. As a numerical example, a three-span continuous girder bridge is simulated, and the corresponding stiffness, the damage location and degree, and the damping parameter are identified accurately. It is verified that the method is suitable for the dynamic signal with high noise-signal ratio; the convergence speed is fast and this method is feasible for application.

  8. Neural networks-based damage detection for bridges considering errors in baseline finite element models

    Science.gov (United States)

    Lee, Jong Jae; Lee, Jong Won; Yi, Jin Hak; Yun, Chung Bang; Jung, Hie Young

    2005-02-01

    Structural health monitoring has become an important research topic in conjunction with damage assessment and safety evaluation of structures. The use of system identification approaches for damage detection has been expanded in recent years owing to the advancements in signal analysis and information processing techniques. Soft computing techniques such as neural networks and genetic algorithm have been utilized increasingly for this end due to their excellent pattern recognition capability. In this study, a neural networks-based damage detection method using the modal properties is presented, which can effectively consider the modelling errors in the baseline finite element model from which the training patterns are to be generated. The differences or the ratios of the mode shape components between before and after damage are used as the input to the neural networks in this method, since they are found to be less sensitive to the modelling errors than the mode shapes themselves. Two numerical example analyses on a simple beam and a multi-girder bridge are presented to demonstrate the effectiveness of the proposed method. Results of laboratory test on a simply supported bridge model and field test on a bridge with multiple girders confirm the applicability of the present method.

  9. Damage detection algorithm-embedded smart sensor node system for bridge structural health monitoring

    Science.gov (United States)

    Park, Jae-Hyung; Ho, Duc-Duy; Kim, Jeong-Tae; Ryu, Yeon-Sun; Yun, Chung-Bang

    2009-03-01

    In this study, a system using autonomous smart sensor nodes is developed for bridge structural health monitoring (SHM). In order to achieve the research goal, the following tasks are implemented. Firstly, acceleration-based and impedancebased smart sensor nodes are designed. Secondly, an autonomous operation system using smart sensor nodes is designed for hybrid health monitoring using global and local health monitoring methods. Finally, the feasibility and applicability of the proposed system are experimentally evaluated in a lab-scaled prestressed concrete (PSC) girder for which a set of damage scenarios are experimentally monitored by wireless sensor nodes and embedded software.

  10. An innovative steel-concrete joint for integral abutment bridges

    Directory of Open Access Journals (Sweden)

    Bruno Briseghella

    2015-08-01

    Full Text Available Integral abutment bridges are becoming rather common, due to the durability problems of bearings and expansion joints. At the same time, among short- and medium-span bridges, multi-beam steel-concrete composite deck with hot-rolled girder is an economical and interesting alternative to traditional pre-stressed concrete solutions. The two concepts can be linked together to design integral steel-concrete composite bridges with the benefits of two typologies. The most critical aspect for these bridges is usually the joints between deck and piers or abutments. In this paper, an innovative beam-to-pier joint is proposed and a theoretical and experimental study is introduced and discussed. The analyzed connection is aimed at combining general ease of construction with a highly simplified assembly procedure and a good transmission of hogging and sagging moment at the supports in continuous beams. For this purpose, the traditional shear studs, used at the interface between steel beam and upper concrete slab, are also used at the ends of steel profiles welded horizontally to the end plates. To better understand the behaviour of this kind of joints and the roles played by different components, three large-scale specimens were tested and an FE model was implemented. The theoretical and experimental results confirmed the potential of the proposed connection for practical applications and indicated the way to improve its structural behaviour.

  11. Small, Lightweight, Collapsible Glove Box

    Science.gov (United States)

    James, Jerry

    2009-01-01

    A small, lightweight, collapsible glove box enables its user to perform small experiments and other tasks. Originally intended for use aboard a space shuttle or the International Space Station (ISS), this glove box could also be attractive for use on Earth in settings in which work space or storage space is severely limited and, possibly, in which it is desirable to minimize weight. The development of this glove box was prompted by the findings that in the original space-shuttle or ISS setting, (1) it was necessary to perform small experiments in a large general-purpose work station, so that, in effect, they occupied excessive space; and it took excessive amounts of time to set up small experiments. The design of the glove box reflects the need to minimize the space occupied by experiments and the time needed to set up experiments, plus the requirement to limit the launch weight of the box and the space needed to store the box during transport into orbit. To prepare the glove box for use, the astronaut or other user has merely to insert hands through the two fabric glove ports in the side walls of the box and move two hinges to a locking vertical position (see figure). The user could do this while seated with the glove box on the user fs lap. When stowed, the glove box is flat and has approximately the thickness of two pieces of 8-in. (.20 cm) polycarbonate.

  12. Mathematical bridges

    CERN Document Server

    Andreescu, Titu; Tetiva, Marian

    2017-01-01

    Building bridges between classical results and contemporary nonstandard problems, Mathematical Bridges embraces important topics in analysis and algebra from a problem-solving perspective. Blending old and new techniques, tactics and strategies used in solving challenging mathematical problems, readers will discover numerous genuine mathematical gems throughout that will heighten their appreciation of the inherent beauty of mathematics. Most of the problems are original to the authors and are intertwined in a well-motivated exposition driven by representative examples. The book is structured to assist the reader in formulating and proving conjectures, as well as devising solutions to important mathematical problems by making connections between various concepts and ideas from different areas of mathematics. Instructors and educators teaching problem-solving courses or organizing mathematics clubs, as well as motivated mathematics students from high school juniors to college seniors, will find Mathematical Bri...

  13. Carbon Fibre-reinforced Polymer Strengthening and monitoring of the Gröndals Bridge in Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Hejll, A.; James, G.

    2007-01-01

    The Gröndal Bridge is a large freivorbau bridge (prestressed concrete box bridge), approximately 400 m in length with a free span of 120 m. It was opened to tram traffic in the year 2000. Just after opening cracks were noticed in the webs, these cracks have then increased, the size of the largest...

  14. The Stability of a Steel Welded Girder with Bending and Shear Forces Included

    Directory of Open Access Journals (Sweden)

    Sygulski Ryszard

    2017-03-01

    Full Text Available The stability of the element of a steel welded girder subjected to bending and shear forces is considered. The considered element is a rectangular plate supported on boundary. The type of a plate boundary conditions depend on the types (thickness of the stiffeners. Considered plate is loaded by in-plane forces causing bending and shear effects. The Finite Element Method was applied to carry out the analysis. Additionally the Boundary Element Method in terms of boundary-domain integral equation was applied to evaluate the critical shear loading.

  15. Hazards Classification of MTSQ Fuze M582A1 in Ammunition Box

    Science.gov (United States)

    1985-11-01

    A-5 (97% RDX ). SINGLE PACKAGE TESTS Three ammunition boxes each containing eight fuzes and internal packaging were used in the conduct of three single...Reynolds Industries RP-87 exploding bridge wire (EBW) detonator, which has an output charge consisting of 47 MG RDX plus a MK9 lead containing 363 MG...the box itself and fuzes were ejected from the pit. Several of the cardboard packing tubes were observed to smolder for approximately 20 minutes

  16. Fatigue analysis and life prediction of composite highway bridge decks under traffic loading

    Directory of Open Access Journals (Sweden)

    Fernando N. Leitão

    Full Text Available Steel and composite (steel-concrete highway bridges are currently subjected to dynamic actions of variable magnitude due to convoy of vehicles crossing on the deck pavement. These dynamic actions can generate the nucleation of fractures or even their propagation on the bridge deck structure. Proper consideration of all of the aspects mentioned pointed our team to develop an analysis methodology with emphasis to evaluate the stresses through a dynamic analysis of highway bridge decks including the action of vehicles. The design codes recommend the application of the curves S-N associated to the Miner's damage rule to evaluate the fatigue and service life of steel and composite (steel-concrete bridges. In this work, the developed computational model adopted the usual mesh refinement techniques present in finite element method simulations implemented in the ANSYS program. The investigated highway bridge is constituted by four longitudinal composite girders and a concrete deck, spanning 40.0m by 13.5m. The analysis methodology and procedures presented in the design codes were applied to evaluate the fatigue of the bridge determining the service life of the structure. The main conclusions of this investigation focused on alerting structural engineers to the possible distortions, associated to the steel and composite bridge's service life when subjected to vehicle's dynamic actions.

  17. Impact of usability on efforts to bridge the digital divide

    CSIR Research Space (South Africa)

    Adebesin, F

    2010-11-01

    Full Text Available to Bridge the Digital Divide Funmi Adebesin Meraka Institute of the CSIR and School of Computing, UNISA P.O. Box 395 Pretoria, 0001, South Africa fadebesin@csir.co.za Paula Kotzé Meraka Institute of the CSIR and School of Computing, UNISA P.O. Box.... To address the problem, international and national initiatives are ongoing to provide access to technologies with the aim of bridging the digital divide. Many of the efforts to narrow the divide have been concerned with the provision of physical...

  18. Simulating the Effects of Surface Roughness on Reinforced Concrete T Beam Bridge under Single and Multiple Vehicles

    Directory of Open Access Journals (Sweden)

    Rahul Kalyankar

    2016-01-01

    Full Text Available This research focuses on the application of the spatial system of finite element modeling for the vehicle-bridge interaction on reinforced concrete US Girder Bridge in order to obtain the effect of surface roughness. Single vehicle and multiple vehicles on reinforced concrete T beam bridge were studied with variable surface roughness profiles. The effects of six different surface roughness profiles (very good, good, measured, average, poor, and very poor were investigated for vehicle-bridge interaction. The values of the Dynamic Amplification Factor (DAF were obtained for single and multiple vehicles on T Beam Bridge for different surface roughness profiles, along with the distances between the axles of heavy vehicle. It was observed that when the bridge has very good, good, measured, and average surface roughness, the DAF values for the single vehicle over the bridge were observed to be within acceptable limits specified by AASHTO. However, for the bridge with multiple vehicles only very good and measured surface roughness profiles showed a DAF and vehicle axle distances within the acceptable limits. From the current studies, it was observed that the spatial system showed reliable responses for predicting the behavior of the bridge under variable road surface roughness conditions and was reliable in vehicle axle detection, and therefore, it has a potential to be use for realistic simulations.

  19. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Bridges are one of the most crucial facilities of transportation networks. Therefore, evaluation of the seismic vulnerability of bridge structures is perpetually regarded topic for researchers. In this study, we developed seismic fragility curves for a continuous steel box girder bridge considering the effect of differentlevels of ...

  20. Assessing Corrosion Damage and Corrosion Progression in Multistrand Anchor Systems in Use at Corps Projects

    Science.gov (United States)

    2013-07-01

    evaluation of prestressing steel strands in concrete bridges . Final Report, Phase I: Technology Review, Transportation Research Board National Research...Inspection methods and techniques to determine non- visible corrosion of prestressing strands in concrete bridge components. Pennsylvania Department...cracking in post-tensioned concrete box girder bridges and retrofit procedures. Precast/ Prestressed Concrete Institute Journal, March- April. Podolny, W

  1. INVESTIGATION OF LAUNCHING PROCESS FOR STEEL REINFORCED CONCRETE FRAMEWORK OF LARGE BRIDGES

    Directory of Open Access Journals (Sweden)

    V. A. Grechukhin

    2017-01-01

    Full Text Available Bridges are considered as the most complicated, labour-consuming and expensive components in roadway network of the Republic of Belarus. So their construction and operation are to be carried out at high technological level. One of the modern industrial methods is a cyclic longitudinal launching of large frameworks which provide the possibility to reject usage of expensive auxiliary facilities and reduce a construction period. There are several variants of longitudinal launching according to shipping conditions and span length: without launching girder, with launching girder, with top strut-framed beam in the form of cable-stayed system, with strut-framed beam located under span. While using method for the cyclic longitudinal launching manufacturing process of span is concentrated on the shore. The main task of the investigations is to select economic, quick and technologically simple type of the cyclic longitudinal launching with minimum resource- and labour inputs. Span launching has been comparatively analyzed with temporary supports being specially constructed within the span and according to capital supports with the help of launching girder. Conclusions made on the basis of calculations for constructive elements of span according to bearing ability of element sections during launching and also during the process of reinforced concrete plate grouting and at the stage of operation have shown that span assembly with application of temporary supports does not reduce steel spread in comparison with the variant excluding them. Results of the conducted investigations have been approbated in cooperation with state enterprise “Belgiprodor” while designing a bridge across river Sozh.

  2. Alignment and girder position of MSE septa in the new LSS4 extraction channel of the SPS

    CERN Document Server

    Balhan, B; Rizzo, A; Weterings, W; CERN. Geneva. SPS and LHC Division

    2002-01-01

    For the extraction of the beam from the Super Proton Synchrotron (SPS) to ring 2 of the Large Hadron Collider (LHC) and the CERN Neutrino to Gran Sasso (CNGS)facility, a new fast-extraction system is being constructed in the long straight section LSS4 of the SPS. Besides extraction bumpers, enlarged aperture quadrupoles and extraction kicker magnets (MKE), six conventional DC septum magnets (MSE) are used. These magnets are mounted on a single rigid support girder, pre-aligned so as to follow the trajectory of the extracted beam and optimise the available aperture. The girder has been motorised in order to optimise the local SPS aperture during setting up, so as to avoid the risk of circulating beam impact on the septum coils. In this note, we briefly present the trajectory and apertures of the beam, we describe the calculations and methods that have been used to determine the magnet position on the girder, and finally we report on the details of the girder movement and alignment.

  3. Aerodynamic stability of long span suspension bridges with low torsional natural frequencies

    DEFF Research Database (Denmark)

    Andersen, Michael Styrk; Johansson, Jens; Brandt, Anders

    2016-01-01

    Classical flutter of suspended bridge decks can be avoided if the torsional frequencies are lower than the vertical. Wind tunnel tests of single boxes and twin box section models with torsional natural frequencies above and below the vertical frequency has been conducted. Flutter was avoided in a...

  4. Mechanical integrity and sustainability of pre-stressed concrete bridge girders repaired by epoxy injection – phase 1.

    Science.gov (United States)

    2017-02-02

    At present, there is a need to assess the mechanical integrity and sustainability of pre-stressed concrete beams during the entire life cycle of the built infrastructure. According to the NCHRP (Tadros et al., 2010), further research to develop fi...

  5. Spirit Boxes: Expressions of Culture.

    Science.gov (United States)

    DeMuro, Ted

    1984-01-01

    After studying the culture and art of the ancient civilizations of South America, Mesopotamia, Greece, and Egypt, secondary level art students made spirit boxes as expressions of the various cultures. How to make the boxes and how to prepare the face molds are described. (RM)

  6. Being Creative "Inside the Box"

    Science.gov (United States)

    Tomascoff, Rocky

    2011-01-01

    Artist Joseph Cornell (1903-1972) created wonderful environments inside boxes using mostly found objects. They were often Surrealistic in nature. Some boxes were designed with glass fronts, and others were meant to be interactive with the viewer, wherein the objects could be handled. With Joseph Cornell in mind, the author introduces an art…

  7. Box-and-Whisker Plots.

    Science.gov (United States)

    Larsen, Russell D.

    1985-01-01

    Box-and-whisker plots (which give rapid visualization of batches of data) can be effectively used to present diverse collections of data used in traditional first-year chemistry courses. Construction of box-and-whisker plots and their use with bond energy data and data on heats of formation and solution are discussed. (JN)

  8. Bridge resource program.

    Science.gov (United States)

    2013-09-01

    The mission of Rutgers Universitys Center for Advanced Infrastructure and Transportation (CAIT) Bridge Resource Program (BRP) is to provide bridge engineering support to the New Jersey Department of Transportation (NJDOT)s Bridge Engineering an...

  9. NDT of bridge pins on Pennsylvania Dept. of Transportation structures

    Science.gov (United States)

    Miller, William J.; Chaney, M. K.

    1995-05-01

    The Pennsyulvania Department of Transportation conducted a two phase investigation of all fracture critical pin hanger assemblies between 1988 and 1991 of 23 bridges. The first phase consisted of visually inspecting and documenting the condition of the pin assemblies. The second phase involved nondestructive testing of the pins and any hanger assembly parts that the engineer requested. This testing was performed by consultant engineering firms under contract with individual Penn DOT Engineering Districts. The Mehoopany Bridge was the only structure which was tested exclusively by the department's personnel. Twenty fracture critical bridges were consequently retrofitted with support girders or rod support assemblies. The remaining three locations had the pin hanger assemblies removed and the structures were made continuous. Also, the pins were replaced at some of the 20 locations. All removed pins were requested to be retained and sent to the Department's Materials and Testing Laboratory for evaluation testing. A large number of the pins were destroyed during removal and some were discarded during construction. The following criteria was established by department personnel for MTD's testing of the pins and defect comparisons with consulting engineer's test results: 1) modified ASTM A388 standard test, using 18 degree transducer; 2) 1/16 inch saw notches used as reference standard; 3) straight beam and angle test probes for UT of in-place pins; 4) 45 degree and 70 degree angle beam bore hole test probe for verification of pin defects.

  10. Multi-scale investigation of tensile creep of ultra-high performance concrete for bridge applications

    Science.gov (United States)

    Garas Yanni, Victor Youssef

    Ultra-high performance concrete (UHPC) is relatively a new generation of concretes optimized at the nano and micro-scales to provide superior mechanical and durability properties compared to conventional and high performance concretes. Improvements in UHPC are achieved through: limiting the water-to-cementitious materials ratio (i.e., w/cm ≤ 0.20), optimizing particle packing, eliminating coarse aggregate, using specialized materials, and implementing high temperature and high pressure curing regimes. In addition, and randomly dispersed and short fibers are typically added to enhance the material's tensile and flexural strength, ductility, and toughness. There is a specific interest in using UHPC for precast prestressed bridge girders because it has the potential to reduce maintenance costs associated with steel and conventional concrete girders, replace functionally obsolete or structurally deficient steel girders without increasing the weight or the depth of the girder, and increase bridge durability to between 75 and 100 years. UHPC girder construction differs from that of conventional reinforced concrete in that UHPC may not need transverse reinforcement due to the high tensile and shear strengths of the material. Before bridge designers specify such girders without using shear reinforcement, the long-term tensile performance of the material must be characterized. This multi-scale study provided new data and understanding of the long-term tensile performance of UHPC by assessing the effect of thermal treatment, fiber content, and stress level on the tensile creep in a large-scale study, and by characterizing the fiber-cementitious matrix interface at different curing regimes through nanoindentation and scanning electron microscopy (SEM) in a nano/micro-scale study. Tensile creep of UHPC was more sensitive to investigated parameters than tensile strength. Thermal treatment decreased tensile creep by about 60% after 1 year. Results suggested the possibility of

  11. Application study on the first cable-stayed bridge with CFRP cables in China

    Directory of Open Access Journals (Sweden)

    Kuihua Mei

    2015-08-01

    Full Text Available In order to push forward the development of CFRP cable-stayed bridge and accumulate experiences, the study on the application of the first cable-stayed bridge with CFRP cables in China was carried out. The design essentials of main components of the bridge were introduced and its integral performances, including static properties, dynamic properties and seismic response were analyzed using finite element method. A new bond-type anchorage was developed and the processes of fabricating and installing CFRP cables were elaborated. Based on the results of construction simulation, a tension scheme for bridge was propound. During constructing, the stresses and displacement of girder and pylon, as well as the forces and stresses of cables, were tested. The results indicate that all sections of the bridge could meet the requirements of the ultimate bearing capacity and normal service; the performance of the anchorage is good and the stresses in each cable system are similar; the tested values accord well with the calculated values. Further, creep deformation of the resin in anchorages under service load is not obvious. All these results demonstrate that the first application of CFRP cables in the cable-stayed bridge in China is successful.

  12. Design, fabrication and erection of Queen Mall Bridge; Queen mall kyo no sekkei seisaku kasetsu

    Energy Technology Data Exchange (ETDEWEB)

    Arai, M.; Ishii, A.; Shinohara, T. [Sumitomo Heavy Industries, Ltd., Tokyo (Japan)

    1997-12-20

    This paper describes design, fabrication and erection of Queen Mall Bridge, which is a new landmark in Minato-Mirai Yokohama. This bridge is two-span continuous cable stayed pedestrian bridge with a roof, and has a length 72.2 m, a width 18 m and a weight about 1,050 t. This bridge connects between the Queen`s Square and the second floor of Pacifico Yokohama. Achieving harmonious impression of the newly designed bridge in this area, glass roof was employed and all-weld method was applied to the in-site jointing of main girders and main tower in addition to the essential structural design. Since all-weld method was applied to the in-site jointing, highly accurate fabrication was considered during the in-site jointing. Due to the heavy traffic of the road below the bridge, the erection time was shortened under the severe erection conditions at night by large block method. Especially, accuracy control was considered for the whole shape management. Pre-assemble of all members was conducted just near the erection site, only 500 m away from the site, to shorten the construction time. 1 ref., 5 figs.

  13. Environmental durability of reinforced concrete deck girders strengthened for shear with surface-bonded carbon fiber-reinforced polymer : final report.

    Science.gov (United States)

    2009-05-01

    This research investigated the durability of carbon fiber-reinforced polymer composites (CFRP) used for shear strengthening reinforced concrete deck girders. Large beams were used to avoid accounting for size effects in the data analysis. The effort ...

  14. On the effects of hull-girder vibration upon fatigue strength of a Post-Panamax container ship disaggregated by short-term sea state

    Directory of Open Access Journals (Sweden)

    Fukasawa Toichi

    2014-06-01

    Full Text Available The effects of hull-girder vibration on the fatigue strength of a Post-Panamax container ship are discussed in the present paper. Firstly, the short-term sea states are categorized according to the occurrence probability of each sea state. Time histories of hull-girder stress in short-term sea states are calculated by means of a nonlinear simulation code of ship response assuming that the hull-girder is rigid and flexible. Then, the calculated stress peaks are processed by the rainflow counting method, where two different counting procedures are used based on the considerations of crack propagation behaviors. Finally, the fatigue damage in life time of the ship in each categorized short-term sea state is estimated by means of Miner’s rule. Based on the calculated results, the effects of hull-girder vibrations on the fatigue damage are clarified by disaggregated damage from short-term sea state.

  15. On the effects of hull-girder vibration upon fatigue strength of a Post-Panamax container ship disaggregated by short-term sea state

    Directory of Open Access Journals (Sweden)

    Toichi Fukasawa

    2014-06-01

    Full Text Available The effects of hull-girder vibration on the fatigue strength of a Post-Panamax container ship are discussed in the present paper. Firstly, the short-term sea states are categorized according to the occurrence probability of each sea state. Time histories of hull-girder stress in short-term sea states are calculated by means of a nonlinear simulation code of ship response assuming that the hull-girder is rigid and flexible. Then, the calculated stress peaks are processed by the rainflow counting method, where two different counting procedures are used based on the considerations of crack propagation behaviors. Finally, the fatigue damage in life time of the ship in each categorized short-term sea state is estimated by means of Miner's rule. Based on the calculated results, the effects of hull-girder vibrations on the fatigue damage are clarified by disaggregated damage from short-term sea state.

  16. Microclimate boxes for panel paintings

    DEFF Research Database (Denmark)

    Wadum, Jørgen

    1998-01-01

    The use of microclimate boxes to protect vulnerable panel paintings is, therefore, not a new phenomenon of the past two or three decades. Rather, it has been a concern for conservators and curators to protect these objects of art at home and in transit since the end of the nineteenth century....... The increased number of travelling exhibitions in recent years has heightened the need to protect paintings during circulation (Thomson 1961; Mecklenburg 1991). The use and design of microclimate boxes have been evolving since 1892. These boxes may be divided into three broad groups: those using an active...

  17. Two-dimensional box plot

    OpenAIRE

    Phattrawan Tongkumchum

    2005-01-01

    In this paper we propose a two-dimensional box plot, a simple bivariate extension of the box plot and the scatter plot. This plot comprises a pair of trapeziums oriented in the direction of a fitted straight line, with symbols denoting extreme values. The choice for the fitted straight resistant line showing the relationship between the two variables is Tukey’s resistance line. The main components of the plot are an inner box containing 50% of the projection points of the observations on the ...

  18. Structural evaluation of LIC-310-0396 and FAY-35-17-6.82 box beams with advanced strand deterioration : draft final report - phase II.

    Science.gov (United States)

    2011-09-01

    This report describes the results from the testing of a full scale three span 43 year old adjacent prestressed concrete box beam bridge. This research is the second phase of the overall project entitled Structural Evaluation of LIC-310-0396 Box Be...

  19. DIRECT KICKS IN BOXING

    Directory of Open Access Journals (Sweden)

    Izet Kahrović

    2009-11-01

    Full Text Available Hit directly, giving any impact maximum muscle strength is skill, and it is neces- sary to the exercise and learning to make it perfect. Training begins with oral statement, so that students get to know with the techni- que that works. After oral exposure, it is necessary to create a good notion on technology that is adopted. The best way for the creation of good notion is a good demonstration. In direct training kicks in the box, you need patience and gradualness and there- fore uses a large number of additional exercises. In their work with beginners, in the first class, individual elements of technology, and also direct blow, it is necessary to separate the parts and run them on multiple commands, to later come to the confluence in one command. Direct wounds, with left and right hand, can be run from the towns, on the head and body, from the movement, to step forward, step back and step aside, the remedy to the left and right side. Left direct is taking out from a running protrusion hands, but kick, which is a pro- duct of the system, ankle-knee-pelvis and shoulder forward horizontaly. Set at the time of stripes, body weight over the left leg. Right direct from the place, starting ekscentrical reflecsive impuls of a extensor muscle in ankle, knee and joint of a hip.This kind of a sud- den movement is running simultaneously with the rotation of the body around vertical (longitudinal axis, with the transfer body weight on the left leg. Further movement to the hand which serves as a lever, which is transmitted through the power stroke

  20. Analysis of post-tensioned girders structural behaviour using continuous temperature and strain monitoring

    Science.gov (United States)

    Bednarski, Ł.; Sieńko, R.; Howiacki, T.

    2017-10-01

    This article presents the possibility of using structural health monitoring system data for the analysis of structure’s operation during its life cycle. Within the specific case study it was proved, that continuous, automatic and long term monitoring of selected physical quantities such as strains and temperatures, can significantly improve the assessment of technical condition by identifying hazardous phenomena. In this work the analysis of structural behaviour of post-tensioned girders within the roofing of sport halls in Cracow, Poland, was performed based on measurement results and verified by numerical model carried out in SOFiSTiK software. Thanks to the possibility of performing calculations in real time and informing the manager of the object about abnormalities it is possible to manage the structure in effective way by, inter alia, planning the renovations or supporting decisions about snow removal.

  1. Effect of Torsion on Externally Prestressed Segmental Concrete Bridge with Shear Key

    OpenAIRE

    M. A. Algorafi; A. A. A. Ali; Jaafar, M.S.; I. Othman; M. P. Anwar; Rashid, R

    2009-01-01

    Externally Prestressed Segmental (EPS) concrete box sections are widely used in the construction of bridge structures today. EPS concept has become an attractive tool for rehabilitation and strengthening of existing bridges which have insufficient strength and/or excessive deflection and cracking. Problem statement: EPS bridges are affected by combined stresses (bending, shear, normal, and torsional) at the joint interface between the segments. However, very limited researchers studied this t...

  2. A Mueller bridge set for cryogenic temperature measurements

    DEFF Research Database (Denmark)

    Diamond, J.M.

    1966-01-01

    An a.c. Mueller bridge set for resistance thermometry at cryogenic temperature is described. A commercial tuned null detector is used at an operating frequency of 1025 c/s. The set includes a high stability oscillator, line reject filter, phase shifter, Q multiplier and selector box. The latter...

  3. Improved connection details for adjacent prestressed bridge beams.

    Science.gov (United States)

    2015-03-01

    Bridges with adjacent box beams and voided slabs are simply and rapidly constructed, and are well suited to : short to medium spans. The traditional connection between the adjacent members is a shear key lled with a : conventional non-shrink grout...

  4. SYNTHESIS AND CHARACTERIZATION OF AN OXO-BRIDGED ...

    African Journals Online (AJOL)

    a

    SYNTHESIS AND CHARACTERIZATION OF AN OXO-BRIDGED RHENIUM(V). COMPLEX WITH AN AMINE-PHENOL TETRADENTATE LIGAND. A. Abrahams1, T.I.A. Gerber1* and Peter Mayer2. 1Department of Chemistry, Nelson Mandela Metropolitan University, P.O. Box 77000, 6031. Port Elizabeth, South Africa.

  5. Calculation methods study on hot spot stress of new girder structure detail

    Science.gov (United States)

    Liao, Ping; Zhao, Renda; Jia, Yi; Wei, Xing

    2017-10-01

    To study modeling calculation methods of new girder structure detail's hot spot stress, based on surface extrapolation method among hot spot stress method, a few finite element analysis models of this welded detail were established by finite element software ANSYS. The influence of element type, mesh density, different local modeling methods of the weld toe and extrapolation methods was analyzed on hot spot stress calculation results at the toe of welds. The results show that the difference of the normal stress in the thickness direction and the surface direction among different models is larger when the distance from the weld toe is smaller. When the distance from the toe is greater than 0.5t, the normal stress of solid models, shell models with welds and non-weld shell models tends to be consistent along the surface direction. Therefore, it is recommended that the extrapolated point should be selected outside the 0.5t for new girder welded detail. According to the results of the calculation and analysis, shell models have good grid stability, and extrapolated hot spot stress of solid models is smaller than that of shell models. So it is suggested that formula 2 and solid45 should be carried out during the hot spot stress extrapolation calculation of this welded detail. For each finite element model under different shell modeling methods, the results calculated by formula 2 are smaller than those of the other two methods, and the results of shell models with welds are the largest. Under the same local mesh density, the extrapolated hot spot stress decreases gradually with the increase of the number of layers in the thickness direction of the main plate, and the variation range is within 7.5%.

  6. Box Plots: Basic and Advanced.

    Science.gov (United States)

    Mullenex, James L.

    1990-01-01

    Describes a five-number summary which is a display of the minimum value, lower quartile, median, upper quartile, and maximum value. Indicates how to draw box plots as graphical representations of a five-number summary. (YP)

  7. Implementace hry Dots and Boxes

    OpenAIRE

    Balko, Martin

    2010-01-01

    Title: Dots and Boxes implementation Author: Martin Balko Department: Department of Applied Mathematics Supervisor: RNDr. Ondřej Pangrác, Ph.D. Supervisor's email address: Abstract: The presented thesis deals with the analysis of a popular logical game Dots and Boxes and its generalized versions. It focuses on the different methods and algorithms of opponent's artificial intelligence. The result of the work is implementation of the generalized version of this game in w...

  8. Practical cable tension adjustment based upon the satisfaction concept of bridge designers; Sekkeisha no manzokudo wo koryo shita fuzzy cable choryoku choseiho

    Energy Technology Data Exchange (ETDEWEB)

    Kaneyoshi, M.; Tanaka, H. [Hitachi Zosen, Tokyo (Japan)] Furuta, H. [Kansai Univ., Osaka (Japan)

    1998-07-21

    Cable tension adjustment of bridge beam of cable stayed bridge and so forth that uses cable as a structural element is classified into (1) pre-stress adjustment of cable at design level, (2) slim adjustment required at erection level. The former deals with the structurally high dimensional statically indeterminate structures like cable-stayed bridges and is a process for carrying out economical design by making the stress resultant of main girder small due to the introduction of appropriate pre-stress stress on this cable. The later is the process of getting rid off the errors caused in cable tension and camber of girder and tower regarding various errors such as design, fabrication and erection errors. The authors developed analysis method using fuzzy regression analysis and this has been applied in number of practical bridges. In this research, much more practical method is developed where the aspire of designer can be introduced easily by applying the satisfaction concept. By using this, pre-stress adjustment and shim adjustment of cable can be possible in a practical way. 9 refs., 7 figs., 8 tabs.

  9. Toward Better Understanding of Turbulence Effects on Bridge Aerodynamics

    Directory of Open Access Journals (Sweden)

    Shuyang Cao

    2017-12-01

    Full Text Available With the trend of variable cross-sections for long-span bridges from truss-stiffened to quasi-streamlined, and then to multiple-box cross-section geometries, the importance of aeroelastic performance is becoming increasingly significant in wind-resistant design. This article shows that there is clearly insufficient qualitative as well as quantitative understanding of turbulence effects on bridge aerodynamics, particularly the mechanisms behind them. Although turbulence might help the stabilization of long-span bridges, and is thus not a conclusive parameter in wind-resistant design, turbulence effects on the aerodynamic and aeroelastic behaviors of a bridge need to be better understood because interaction between a bridge and turbulence always exists. This article also briefly introduces a newly developed multiple-fan wind tunnel that is designed to control turbulence to assist the study of turbulence effects.

  10. Energy-based damping evaluation of cable-stayed bridges and its application to Tsurumi Tsubasa bridge; Shachokyo shindo gensui no energy teki hyokaho to Tsurumi Tsubasakyo eno tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, H. [Saitama University, Saitama (Japan). Faculty of Engineering; Takano, H.; Ogasawara, M.; Shimosato, T. [Metropolitan Expressway Public Corp., Tokyo (Japan); Kato, M.; Kato, H. [NKK Corp., Tokyo (Japan)

    1996-07-21

    This paper provides and discusses a more common energy-based evaluation method of vibration damping in cable-stayed bridges. This method was applied to data obtained from the field vibration test of the Tsurumi Tsubasa Bridge. The damping was defined as dissipation energy in one cycle against the total potential energy. The dissipation energy from shoe friction, aerodynamic damping, and dampers for cables was added to the method proposed by Yamaguchi, et. al., in which the energy of girders, towers, and cables were quantitated, and the dissipation energy was determined from the loss factor of each constituent, to evaluate the damping of whole bridge. Thus, a more common energy-based evaluation method was provided. This method was applied to the damping obtained from the field vibration test of Tsurumi Tsubasa Bridge. Consequently, it was found that the damping of whole bridge was significantly affected by the shoe friction, aerodynamic damping, and dampers for cables. Distinguished damping characteristics of the Tsurumi Tsubasa Bridge could be explained by the energy-based evaluation. Validity of the energy-based evaluation method for damping of cable-stayed bridges was demonstrated. 15 refs., 9 figs., 6 tabs.

  11. Thinking Outside the Box

    Energy Technology Data Exchange (ETDEWEB)

    Green, Lorne [World Nuclear Transport Institute, Remo House, 310-312 Regent Street, London, W1B 3AX (United Kingdom)

    2009-06-15

    The World Nuclear Transport Institute was formed to fill a need to provide a dedicated vehicle for the radioactive transport and packaging industry sectors worldwide, to exchange information and ideas, all with a view to working toward consolidated industry positions on the key issues affecting safe, efficient and reliable transport. WNTI was also intended to be a strong voice for industry in those international and national bodies where deliberations on such transport safety issues take place. The very fact that companies, sometimes in competition with each other, were prepared to come together in this way, reflects two important points: firstly, it represents an acknowledgement on industry's part that safe, effective and reliable transport is the sine qua non, the absolute essential. And second, it is a recognition that it is enhanced to the extent that industry is able to collaborate to this end. This is thinking outside the box. Another important attribute of safety is 'stability'. Everyone likes to know where he or she stands. The radioactive materials packaging and transport industry thrives within a stable regulatory framework for safety. For a stable regulatory regime allows operators to be properly trained; it allows operators to become familiar with safety requirements, and to be at ease with them. Stability is conducive to safety and efficiency. Stability is good for business too - for stability in package and transport requirements allows sufficient time for a fair return on investment in expensive package design, manufacture, licensing and use over time. Stability should not, however, be opposed to creativity. From experience we can develop new thinking to improve efficiency as illustrated in examples of work related to the packaging and transport of Uranium Concentrates for instance.. Another example is work within WNTI on the thermal test requirements for the packaging of uranium hexafluoride. The robustness of packages is based on the

  12. Comparison of black-box, glass-box and open-box software for aiding conceptual understanding

    OpenAIRE

    Hosein, Anesa; Aczel, James; Clow, Doug; Richardson, John T E

    2008-01-01

    Three mathematical software types: black-box (no steps shown), glass-box (steps shown) and open-box (interactive steps) were used by 32 students to solve conceptual and procedural tasks on the computer via remote observation. Comparison of the three software types suggests that there is no difference in the scores that students receive for conceptual understanding tasks. Students using the black-box are more likely to explore answers than students using the glass and open-box software.

  13. Estimation of hull girder vertical bending moments including non-linear and flexibility effects using closed form expressions

    DEFF Research Database (Denmark)

    Pedersen, Preben Terndrup; Jensen, Jørgen Juncher

    2009-01-01

    A simple but rational procedure for prediction of extreme wave-induced hull girder bending moment is presented. The procedure takes into account main ship hull characteristics such as: length, breadth, draught, block coefficient, bow flare coefficient, forward speed and hull flexibility. The wave......-induced loads are evaluated for specific operational profiles. Non-linearity in the wave bending moment is modeled using results derived from a second-order strip theory and water entry solutions for wedge type sections. Hence, bow flare slamming is accounted for through a momentum type of approach......-linear strip theory calculations and supplemented with new closed form results for the hogging bending moment. Focus is on the extreme hull girder hogging bending moment. Due to the few input parameters this procedure can be used to estimate the wave-induced bending moments at the conceptual design phase...

  14. 30 CFR 56.12006 - Distribution boxes.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distribution boxes. 56.12006 Section 56.12006... Distribution boxes. Distribution boxes shall be provided with a disconnecting device for each branch circuit... visual observation when such a device is open and that the circuit is deenergized, the distribution box...

  15. 30 CFR 57.12006 - Distribution boxes.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Distribution boxes. 57.12006 Section 57.12006... and Underground § 57.12006 Distribution boxes. Distribution boxes shall be provided with a... deenergized, and the distribution box shall be labeled to show which circuit each device controls. ...

  16. First-aid boxes - Reminder

    CERN Multimedia

    GS Department

    2010-01-01

    With a view to ensuring optimum use of the first-aid boxes on the CERN site, we should like to remind you of various changes introduced in March 2009: The TSO of the buildings concerned is responsible for the first-aid boxes, including checking their contents.   First-aid boxes may be restocked ONLY at the CERN stores (SCEM No. 54.99.80). This is no longer possible at the Infirmary. The associated cost is charged to the Departments.   First-aid boxes should be used only for mild injuries. All other cases should be referred to the Medical Service Infirmary (Bldg. 57 – ground-floor, tel. 73802) between 8.00 a.m. and 5.30 p.m. or to the Fire and Rescue Service (tel. 74444). N.B.: This information does not apply to the red emergency first-aid boxes in the underground areas or to the emergency kits for use in the event of being splashed with hydrofluoric acid.

  17. Puentes extradosados: evolución y tendencias actuales

    Directory of Open Access Journals (Sweden)

    José Miguel Benjumea Royero

    2012-09-01

    Full Text Available Since their appearance in 1994, extradosed bridges have played an important role in road and railway projects, competing (in medium span lengths with cables-stayed and prestressed box girder bridges. At a regional level, extradosed bridges have been implemented more frequently in Asia, but recent projects developed in Europe and America show a growing interest in this typology. Consequently, this paper is aimed at offering a survey viewpoint on the evolution of extradosed bridges, from their origin to their current applications. This paper is also intended to show the adopted structural trends by presenting existing extradosed bridges, bridges under construction, and newly designed bridges. Finally, the main advantages and disadvantages of this type of bridges are analyzed and compared to cable-stayed and prestressed box girder bridges.

  18. Identifying competencies of boxing coaches

    Directory of Open Access Journals (Sweden)

    Ioannis Tasiopoulos

    2014-10-01

    Full Text Available The purpose of this study was to find out the management skills required by boxing coaches to administrate their clubs. For the purposes of this study a scale was constructed which was answered by 98 boxing coaches. Explanatory factor analysis revealed seven factors: Communication-public relations (5 items, event management (4 items, management techniques (4 items, new technologies (4 items, prevention-safety (2 items, sport (5 items and sports facilities (2 items. The Cronbach of the scale was 0.85. The five competencies that rated by the coaches were: Supervisors of the area of training, maintaining excellent communication with athletes, using new technologies (e-mail, internet, handling disciplinary matters, accidents, complaints and reports on some sporting games and promoted harmony among athletes. We concluded that boxing coaches understand that the competencies required for meeting their obligations, were related to sports, prevention, safety and communications-public relations.

  19. Bridging consent: from toll bridges to lift bridges?

    Directory of Open Access Journals (Sweden)

    Knoppers Bartha

    2011-10-01

    Full Text Available Abstract Background The ability to share human biological samples, associated data and results across disease-specific and population-based human research biobanks is becoming increasingly important for research into disease development and translation. Although informed consent often does not anticipate such cross-domain sharing, it is important to examine its plausibility. The purpose of this study was to explore the feasibility of bridging consent between disease-specific and population-based research. Comparative analyses of 1 current ethical and legal frameworks governing consent and 2 informed consent models found in disease-specific and population-based research were conducted. Discussion Ethical and legal frameworks governing consent dissuade cross-domain data sharing. Paradoxically, analysis of consent models for disease-specific and population-based research reveals such a high degree of similarity that bridging consent could be possible if additional information regarding bridging was incorporated into consent forms. We submit that bridging of consent could be supported if current trends endorsing a new interpretation of consent are adopted. To illustrate this we sketch potential bridging consent scenarios. Summary A bridging consent, respectful of the spirit of initial consent, is feasible and would require only small changes to the content of consents currently being used. Under a bridging consent approach, the initial data and samples collection can serve an identified research project as well as contribute to the creation of a resource for a range of other projects.

  20. Early-Warning Method of Train Running Safety of a High-Speed Railway Bridge Based on Transverse Vibration Monitoring

    Directory of Open Access Journals (Sweden)

    You-Liang Ding

    2015-01-01

    Full Text Available Making use of long-term transverse vibration monitoring data of DaShengGuan Bridge, the early-warning method of train running safety of the high-speed railway bridge is established by adopting principal component analysis (PCA method. Firstly, the root mean square (RMS of the transverse acceleration of the main girder is used as the monitoring parameter for the train running safety. The correlation model between the RMS values measured from different positions is further adopted as the evaluating model for the train running safety. Finally, the effects of the environmental changes on the evaluating model are eliminated using the PCA method and the warning index for the train running safety is further constructed. The analysis results show that the correlation between the RMS values of the accelerations from different measuring positions on the main girder can be analyzed by a quadratic polynomial fitting model. The PCA method can effectively remove the environmental effects on the quadratic polynomial fitting model. The proposed warning method provides a good capability for detecting the abnormal changes of the measured transverse accelerations and hence it is suitable for early-warning of the train running safety.

  1. Bridge vehicle impact assessment.

    Science.gov (United States)

    2011-12-01

    Bridges in New York State have been experiencing close to 200 bridge hits a year. These : accidents are attributed to numerous factors including: improperly stored equipment on trucks; : violation of vehicle posting signs; illegal commercial vehicles...

  2. Movable bridge maintenance monitoring.

    Science.gov (United States)

    2013-10-01

    Movable bridges have particular maintenance issues, which cost considerably more than those of fixed bridges, : mostly because of the complex interaction of the mechanical, electrical and structural components. In order to track : maintenance and ope...

  3. 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....

  4. Bridge Crossing Simulator

    Science.gov (United States)

    2014-10-07

    support the durability testing of Military Bridging and Gap Crossing Equipment. 15. SUBJECT TERMS Bridge Crossing Simulator Trilateral Design... Trilateral Design and Test Code for Military Bridging and Gap Crossing Equipment (TDTC) 1* is derived based on the number of samples the test bridge...Automotive and Armaments Command TARDEC U.S. Army Tank-Automotive Research, Development and Engineering Center TDTC Trilateral Design and Test Code

  5. 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......, and as an example the reliability profile and a sensitivity analyses for a corroded reinforced concrete bridge is shown....

  6. Expo-Box Contact Us

    Science.gov (United States)

    EPA-Expo-Box is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases, mode

  7. On the Dirichlet's Box Principle

    Science.gov (United States)

    Poon, Kin-Keung; Shiu, Wai-Chee

    2008-01-01

    In this note, we will focus on several applications on the Dirichlet's box principle in Discrete Mathematics lesson and number theory lesson. In addition, the main result is an innovative game on a triangular board developed by the authors. The game has been used in teaching and learning mathematics in Discrete Mathematics and some high schools in…

  8. The Bird Box Survey Project

    Science.gov (United States)

    Willis, Patrick

    2014-01-01

    When high school students are asked what's the best part of science class, many will say it's the field trips. Students enjoy engaging in authentic, community-based science outside the classroom. To capitalize on this, Patrick Willis created the Bird Box Survey Project for his introductory field biology class. The project takes students…

  9. Structural Behavior of a Long-Span Partially Earth-Anchored Cable-Stayed Bridge during Installation of a Key Segment by Thermal Prestressing

    Directory of Open Access Journals (Sweden)

    Sang-Hyo Kim

    2016-08-01

    Full Text Available This study investigated structural behavior of long-span partially earth-anchored cable-stayed bridges with a main span length of 810 m that use a new key segment closing method based on a thermal prestressing technique. A detailed construction sequence analysis matched with the free cantilever method (FCM was performed using a three-dimensional finite element (FE model of a partially earth-anchored cable-stayed bridge. The new method offers an effective way of connecting key segments by avoiding large movements resulting from the removal of the longitudinal restraint owing to the asymmetry of axial forces in the girders near the pylons. The new method develops new member forces through the process of heating the cantilever system before installing the key segment and cooling the system continuously after installing key segments. The resulting forces developed by the thermal process enhance the structural behavior of partially earth-anchored cable-stayed bridges owing to decreased axial forces in the girders.

  10. Assessment of the transportation route of oversize and excessive loads in relation to the load-bearing capacity of existing bridges

    Science.gov (United States)

    Doležel, Jiří; Novák, Drahomír; Petrů, Jan

    2017-09-01

    Transportation routes of oversize and excessive loads are currently planned in relation to ensure the transit of a vehicle through critical points on the road. Critical points are level-intersection of roads, bridges etc. This article presents a comprehensive procedure to determine a reliability and a load-bearing capacity level of the existing bridges on highways and roads using the advanced methods of reliability analysis based on simulation techniques of Monte Carlo type in combination with nonlinear finite element method analysis. The safety index is considered as a main criterion of the reliability level of the existing construction structures and the index is described in current structural design standards, e.g. ISO and Eurocode. An example of a single-span slab bridge made of precast prestressed concrete girders of the 60 year current time and its load bearing capacity is set for the ultimate limit state and serviceability limit state. The structure’s design load capacity was estimated by the full probability nonlinear MKP analysis using a simulation technique Latin Hypercube Sampling (LHS). Load-bearing capacity values based on a fully probabilistic analysis are compared with the load-bearing capacity levels which were estimated by deterministic methods of a critical section of the most loaded girders.

  11. Wire position system to consistently measure and record the location change of girders following ground changes

    Science.gov (United States)

    Choi, H. J.; Lee, S. B.; Lee, H. G.; Y Back, S.; Kim, S. H.; Kang, H. S.

    2017-07-01

    Several parts that comprise the large scientific device should be installed and operated at the accurate three-dimensional location coordinates (X, Y, and Z) where they should be subjected to survey and alignment. The location of the aligned parts should not be changed in order to ensure that the electron beam parameters (Energy 10 GeV, Charge 200 pC, and Bunch Length 60 fs, Emittance X/Y 0.481 μm/0.256 μm) of PAL-XFEL (X-ray Free Electron Laser of the Pohang Accelerator Laboratory) remain stable and can be operated without any problems. As time goes by, however, the ground goes through uplift and subsidence, which consequently deforms building floors. The deformation of the ground and buildings changes the location of several devices including magnets and RF accelerator tubes, which eventually leads to alignment errors (∆X, ∆Y, and ∆Z). Once alignment errors occur with regard to these parts, the electron beam deviates from its course and beam parameters change accordingly. PAL-XFEL has installed the Hydrostatic Leveling System (HLS) to measure and record the vertical change of buildings and ground consistently and systematically and the Wire Position System (WPS) to measure the two dimensional changes of girders. This paper is designed to introduce the operating principle and design concept of WPS and discuss the current situation regarding installation and operation.

  12. Safety Analysis of the Patch Load Resistance of Plate Girders: Influence of Model Error and Variability

    Directory of Open Access Journals (Sweden)

    Farzad Shahabian

    2013-12-01

    Full Text Available This study aims to undertake a statistical study to evaluate the accuracy of nine models that have been previously proposed for estimating the ultimate resistance of plate girders subjected to patch loading. For each model, mean errors and standard errors, as well as the probability of underestimating or overestimating patch load resistance, are estimated and the resultant values are compared one to another. Prior to that, the models are initially calibrated in order to improve interaction formulae using an experimental data set collected from the literature. The models are then analyzed by computing design factors associated with a target risk level (probability of exceedance. These models are compared one to another considering uncertainties existed in material and geometrical properties. The Monte Carlo simulation method is used to generate random variables. The statistical parameters of the calibrated models are calculated for various coefficients of variations regardless of their correlation with the random resistance variables. These probabilistic results are very useful for evaluating the stochastic sensitivity of the calibrated models.

  13. Simplified Analytical Method for Optimized Initial Shape Analysis of Self-Anchored Suspension Bridges and Its Verification

    Directory of Open Access Journals (Sweden)

    Myung-Rag Jung

    2015-01-01

    Full Text Available A simplified analytical method providing accurate unstrained lengths of all structural elements is proposed to find the optimized initial state of self-anchored suspension bridges under dead loads. For this, equilibrium equations of the main girder and the main cable system are derived and solved by evaluating the self-weights of cable members using unstrained cable lengths and iteratively updating both the horizontal tension component and the vertical profile of the main cable. Furthermore, to demonstrate the validity of the simplified analytical method, the unstrained element length method (ULM is applied to suspension bridge models based on the unstressed lengths of both cable and frame members calculated from the analytical method. Through numerical examples, it is demonstrated that the proposed analytical method can indeed provide an optimized initial solution by showing that both the simplified method and the nonlinear FE procedure lead to practically identical initial configurations with only localized small bending moment distributions.

  14. Light Therapy Boxes for Seasonal Affective Disorder

    Science.gov (United States)

    Seasonal affective disorder treatment: Choosing a light therapy box Light therapy boxes can offer an effective treatment for seasonal affective disorder. Features such as light intensity, safety, cost and ...

  15. Research on Fluid Viscous Damper Parameters of Cable-Stayed Bridge in Northwest China

    Directory of Open Access Journals (Sweden)

    Xiongjun He

    2017-01-01

    Full Text Available To optimize the aseismic performance of nonlinear fluid viscous dampers (FVD of cable-stayed bridge in the highly seismic zone, Xigu Yellow River Bridge in northwest China is taken as an example. Nonlinear time-history analysis method is used to research on the relation among the internal forces, displacements, and damping parameters of the 650 tonnage FVD. The method of getting the minimum of binary functions is used to obtain the optimal parameters of FVD. Also, the 1 : 1 full-scale FVD model is made and used in the constitutive relation test. Then the test result of the damping parameters can be got by normal equation method. The optimized method to obtain the damping parameters is further verified. The results indicate that seismic response in key positions of the cable-stayed bridge can be reduced by installing longitudinal nonlinear FVD between the towers and girders if choosing reasonable damping parameters C and ξ. The optimal damping parameters can be calculated accurately by the proposed method of optimizing damping parameters of nonlinear FVD, and the constitutive relation test verifies the correctness of the optimization analysis method. Conclusions concerned can be applied to the design of nonlinear FVD for cable-stayed bridges.

  16. Stainless steel prestressing strands and bars for use in prestressed concrete girders and slabs.

    Science.gov (United States)

    2015-08-01

    Corrosion decay on structures has continued to be a challenge in the scientific and engineering : communities, where significant federal and state funds have been spent towards replacement or rehabilitation : of bridges that were damaged by corrosion...

  17. Self-consolidating concrete for prestressed applications - phase I : girder fabrication and pre-erection performance.

    Science.gov (United States)

    2015-04-01

    Prior to statewide acceptance of self-consolidating concrete (SCC) in precast, prestressed bridge member production, the Alabama Department of Transportation sponsored an investigation of the material to be performed by the Auburn University Highway ...

  18. Main: BOX2PSGS2 [PLACE

    Lifescience Database Archive (English)

    Full Text Available BOX2PSGS2 S000204 17-May-1998 (last modified) kehi Box 2 in glutamine synthetase (G...S2) gene in pea (P.s.); Repeated in tandem with a partial palindrome located between the repeats; Located at ca. -300 of pea GS2; Box

  19. The Heuristic Interpretation of Box Plots

    Science.gov (United States)

    Lem, Stephanie; Onghena, Patrick; Verschaffel, Lieven; Van Dooren, Wim

    2013-01-01

    Box plots are frequently used, but are often misinterpreted by students. Especially the area of the box in box plots is often misinterpreted as representing number or proportion of observations, while it actually represents their density. In a first study, reaction time evidence was used to test whether heuristic reasoning underlies this…

  20. Thermal Bridges in Building Construction - Measurements and Calculations

    DEFF Research Database (Denmark)

    Rose, Jørgen

    The thesis investigates detailed calculation methods for evaluating heat loss through building envelope constructions, or more specific, thermal bridges. First a detailed description of the calculation methods, i.e. both calculation programs and guidelines, for calculating typical thermal bridges...... in building envelope constructions is given. After this a validation of both programs and guidelines is presented. The validation is performed by comparing calculated U-values with Guarded Hot Box measurements. The last part of the thesis discusses the possibilities of utilising the results of detailed...

  1. Structural Aspects of Railway Truss Bridges Affecting Transverse Shear Forces in Steel-Concrete Composite Decks

    Directory of Open Access Journals (Sweden)

    Siekierski Wojciech

    2015-03-01

    Full Text Available At the steel-concrete interface, the horizontal shear forces that are transverse to cross beams occur due to joint action of the steel-concrete composite deck and the truss girders. Numerical analysis showed that values of the forces are big in comparison to the longitudinal shear forces. In both cases extreme force values occur near side edges of a slab. The paper studies possibilities of reduction of these shear forces by structural alterations of the following: rigidity of a concrete slab, arrangement of a wind bracing, arrangement of concrete slab expansion joints. An existing railway truss bridge span has been analysed. Numerical analysis shows that it is possible to reduce the values of shear forces transverse to cross beams. It may reach 20% near the side edges of slabs and 23% in the centre of slab width.

  2. Failure Load Test of a CFRP Strengthened Railway Bridge in Oumlrnskoumlldsvik, Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Bergström, Markus; Carolin, Anders

    2009-01-01

    using carbon fiber reinforced polymer (CFRP) rectangular rods epoxy bonded in sawed up slots, e.g., near surface mounted reinforcement. The strengthening was very successful and resulted in a desired shear failure when the bridge was loaded to failure. The load-carrying capacity in bending...... steel reinforcement by approximately 10%, and increased the height of the compressed zone by 100 mm. When the shear failure occurred, the utilization of the compression concrete and CFRP rods were 100 and 87.5%, respectively. This indicates that a bending failure indeed was about to occur, even though......, Sweden is presented. In this particular test the shear capacity of the concrete girders was of primary interest. However, for any reasonable placement of the load (a line load placed transverse to the track direction) a bending failure would occur. This problem was solved by strengthening for flexure...

  3. GPR signal analysis of post-tensioned prestressed concrete girder defects

    Science.gov (United States)

    Liu, Sixin; Weng, Changnian; Jiao, Pengfei; Wang, Fei; Fu, Lei; Meng, Xu; Lei, Linlin

    2013-06-01

    The accurate inspection of the duct condition in post-tensioned prestressed concrete (PPC) is an essential part of GPR concrete inspection. The purpose is to inspect the grouting condition of the ducts where the strands are located, to find out if there is a void in the ducts, and if any water exists. In order to investigate the radar image characteristics of different PPC duct defects, a number of model girders were manufactured. Three major ducts are included in our study: (1) well grouted and no void (normal condition); (2) the duct is half filled, and the void is filled by water or air; and (3) the duct is not filled at all, and the duct is water or air filled. The data corresponding to seven different situations are acquired and processed. It is found that the radar can detect the first interface in the duct, and the detailed structure inside the duct cannot be ‘seen’ from the images directly. Characteristic curves greatly help the interpretation. A completely void duct is the easiest to differentiate from the others. The signature for this situation is characterized by a strong and clear reflection interface which becomes weaker as the void is water filled. The normal condition shows the weakest reflection interface. As for the half void situation, the front scan shows a similar result to the normal condition whether it is water or air filled, and the back scan shows similar features to the completely void situation. The experiment and analysis is helpful and instructive for practical engineering inspection.

  4. [Composite (etched) bridge].

    Science.gov (United States)

    de Kloet, H J; van Pelt, A W

    1996-11-01

    An adhesive or resin-bonded bridge is a tooth saving construction for the replacement of a lost tooth, especially when the abutment teeth are relatively sound. In this article an overview is presented of the different types of resin-bonded bridges, their advantages and disadvantages and their indications. The direct methods are very suited for the immediate replacement of a lost anterior tooth. The all composite adhesive bridge has a survival rate that is surprisingly good.

  5. Numerical Simulation of Vertical Random Vibration of Train-Slab Track-Bridge Interaction System by PEM

    Directory of Open Access Journals (Sweden)

    Zhi-ping Zeng

    2014-01-01

    Full Text Available The paper describes the numerical simulation of the vertical random vibration of train-slab track-bridge interaction system by means of finite element method and pseudoexcitation method. Each vehicle is modeled as four-wheelset mass-spring-damper system with two-layer suspension systems. The rail, slab, and bridge girder are modeled by three-layer elastic Bernoulli-Euler beams connected with each other by spring and damper elements. The equations of motion for the entire system are derived according to energy principle. By regarding rail irregularity as a series of multipoint, different-phase random excitations, the random load vectors of the equations of motion are obtained by pseudoexcitation method. Taking a nine-span simply supported beam bridge traveled by a train consisting of 8 vehicles as an example, the vertical random vibration responses of the system are investigated. Firstly, the suitable number of discrete frequencies of rail irregularity is obtained by numerical experimentations. Secondly, the reliability and efficiency of pseudoexcitation method are verified through comparison with Monte Carlo method. Thirdly, the random vibration characteristics of train-slab track-bridge interaction system are analyzed by pseudoexcitation method. Finally, applying the 3σ rule for Gaussian stochastic process, the maximum responses of train-slab track-bridge interaction system with respect to various train speeds are studied.

  6. 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....

  7. Carbon fiber-reinforced polymer strengthening and monitoring of the grondals bridge in Sweden

    DEFF Research Database (Denmark)

    Täljsten, Björn; Hejll, Arvid; James, Gerard

    2007-01-01

    The Grondal Bridge is a large freivorbau bridge (prestressed concrete box bridge), approximately 400 min length with a free span of 120 m. It was opened to tram traffic in the year 2000. Just after opening cracks were noticed in the webs, these cracks have then increased, the size of the largest...... cracks exceeded 0.5 mm, and at the end of 2001 the bridge was temporarily strengthened. This was carried out with externally placed prestressed steel stays. The reason for the cracking is still debated and will be further discussed in this paper. Nevertheless, it was clear that the bridge needed...... to be strengthened. The strengthening methods used were CFRP plates at the serviceability limit state and prestressed dywidag stays at the ultimate limit state. The strengthening was carried out during 2002. At the same time monitoring of the bridge commenced, using LVDT crack gauges as well as optical fiber sensors....

  8. Prosthetic rehabilitation using adhesive bridge and fixed-fixed bridge on the maxilla and telescopic crown overdenture on mandible

    Directory of Open Access Journals (Sweden)

    Indah Sulistiawaty

    2016-12-01

    Full Text Available Prosthetic rehabilitation is the rehabilitation process of masticatory and esthetics function for patients missing teeth and alveolar bone by means of manufacture and installation of dentures. The prosthetic rehabilitation commonly used include denture adhesive bridge, fixed-fixed bridge, as well as telescopic overdenture. Adhesive bridge is bridge denture consisting of single pontic and two retainer wings attached to the abutment using cement or resin. Fixed-fixed bridge is a bridge denture with rigid connectors on both ends of the pontics, whereas the telescopic crown Overdenture is a removable denture that uses linked precision on the original tooth in the form of primary coping on abutment and secondary coping on the denture. To expose the procedures of prosthetic rehabilitation using adhesive bridge and fixed-fixed bridge on the maxilla and telescopic crown Overdenture on mandible. Male patients aged 32 years came with complaints of difficulty to chew food because he had lost some teeth behind. In the maxilla, teeth are lost in the region of 15 and 16 performed by making the fixed-fixed bridge with abutment teeth 14 and 17. Loss of teeth in the region of 26, performed the manufacture of adhesive bridge with a box preparation on the occlusal 25 and 27. In the mandible, tooth loss in the region of 36,37,46, and 47 performed manufacture of telescopic crown Overdenture with primer coping on the teeth 35.38, 45, and 48 and the secondary coping on a metal frame. Prosthetic rehabilitation especially in the case of loss of back teeth is very important because with the denture patients can chew properly and maintain the stomatognathic system.

  9. Bridge health monitoring metrics : updating the bridge deficiency algorithm.

    Science.gov (United States)

    2009-10-01

    As part of its bridge management system, the Alabama Department of Transportation (ALDOT) must decide how best to spend its bridge replacement funds. In making these decisions, ALDOT managers currently use a deficiency algorithm to rank bridges that ...

  10. Estimation of Tsunami Bore Forces on a Coastal Bridge Using an Extreme Learning Machine

    Directory of Open Access Journals (Sweden)

    Iman Mazinani

    2016-04-01

    Full Text Available This paper proposes a procedure to estimate tsunami wave forces on coastal bridges through a novel method based on Extreme Learning Machine (ELM and laboratory experiments. This research included three water depths, ten wave heights, and four bridge models with a variety of girders providing a total of 120 cases. The research was designed and adapted to estimate tsunami bore forces including horizontal force, vertical uplift and overturning moment on a coastal bridge. The experiments were carried out on 1:40 scaled concrete bridge models in a wave flume with dimensions of 24 m × 1.5 m × 2 m. Two six-axis load cells and four pressure sensors were installed to the base plate to measure forces. In the numerical procedure, estimation and prediction results of the ELM model were compared with Genetic Programming (GP and Artificial Neural Networks (ANNs models. The experimental results showed an improvement in predictive accuracy, and capability of generalization could be achieved by the ELM approach in comparison with GP and ANN. Moreover, results indicated that the ELM models developed could be used with confidence for further work on formulating novel model predictive strategy for tsunami bore forces on a coastal bridge. The experimental results indicated that the new algorithm could produce good generalization performance in most cases and could learn thousands of times faster than conventional popular learning algorithms. Therefore, it can be conclusively obtained that utilization of ELM is certainly developing as an alternative approach to estimate the tsunami bore forces on a coastal bridge.

  11. Intelligente Bauwerke

    DEFF Research Database (Denmark)

    Schneider, Ronald; Fischer, Johannes; Straub, Daniel

    This report describes a system model for assessing and updating the condition state and reliability of bridge structures utilizing inspection and monitoring data. The system model was developed on the basis of an existing continuous single-cell prestressed concrete box girder. The system model...... for quantifying the effect of inspection and monitoring data on the condition state and reliability of a single-cell prestressed concrete box girder. It can be applied by engineers who are not experts in reliability analysis. It can be concluded that the current prototype provides the basis for identifying...... consists of two integrated sub-models: a condition model for predicting the deterioration state of the box girder and a structural model for evaluating the overall system reliability. To model the stochastic deterioration state of bridge structures, we utilize dynamic Bayesian networks (DBN). DBN...

  12. Long-Term Vibration Monitoring of the Effects of Temperature and Humidity on PC Girders with and without Fly Ash considering ASR Deterioration

    Directory of Open Access Journals (Sweden)

    Tuan Minh Ha

    2017-01-01

    Full Text Available Structural responses have been used as inputs in the evaluation procedures of civil structures for years. Apart from the degradation of a structure itself, changes in the environmental conditions affect its characteristics. For adequate maintenance, it is necessary to quantify the environment-induced changes and discriminate them from the effects due to damage. This study investigates the variation in the vibration responses of prestressed concrete (PC girders, which were deteriorated because of the alkali–silica reaction (ASR, concerning ambient temperature and humidity. Three PC girders were exposed to outdoor weather conditions outside the laboratory, one of which had a selected amount of fly ash in its mixture to mitigate the ASR. The girders were periodically vibration tested for one and a half years. It was found that when the temperature and humidity increased, the frequencies and damping ratios decreased in proportion. No apparent variation in the mode shapes could be identified. A finite element model was proposed for numerical verification, the results of which were in good agreement with the measured changes in the natural frequencies. Moreover, the different dynamic performances of the three specimens indicated that the fly ash significantly affected the vibrations of the PC girders under ASR deterioration.

  13. Influence of apparent wave velocity on seismic performance of a super-long-span triple-tower suspension bridge

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2015-06-01

    Full Text Available As one of the main characteristics of seismic waves, apparent wave velocity has great influence on seismic responses of long-span suspension bridges. Understanding these influences is important for seismic design. In this article, the critical issues concerning the traveling wave effect analysis are first reviewed. Taizhou Bridge, the longest triple-tower suspension bridge in the world, is then taken as an example for this investigation. A three-dimensional finite element model of the bridge is established in ABAQUS, and the LANCZOS eigenvalue solver is employed to calculate the structural dynamic characteristics. Traveling wave effect on seismic responses of these long-span triple-tower suspension bridges is investigated. Envelopes of seismic shear force and moment in the longitudinal direction along the three towers, relative displacements between the towers and the girder, and reaction forces at the bottoms of the three towers under different apparent wave velocities are calculated and presented in detail. The results show that the effect of apparent wave velocity on the seismic responses of triple-tower suspension bridge fluctuates when the velocity is lower than 2000 m/s, and the effects turn stable when the velocity becomes larger. In addition, the effects of traveling wave are closely related to spectral characteristics and propagation direction of the seismic wave, and seismic responses of components closer to the source are relatively larger. Therefore, reliable estimation of the seismic input and apparent wave velocity according to the characteristics of the bridge site are significant for accurate prediction of seismic responses. This study provides critical reference for seismic analysis and design of long-span triple-tower suspension bridges.

  14. Covered Bridge Security Manual

    Science.gov (United States)

    Brett Phares; Terry Wipf; Ryan Sievers; Travis Hosteng

    2013-01-01

    The design, construction, and use of covered timber bridges is all but a lost art in these days of pre-stressed concrete, high-performance steel, and the significant growth both in the volume and size of vehicles. Furthermore, many of the existing covered timber bridges are preserved only because of their status on the National Registry of Historic Places or the...

  15. Bridges Expansion Joints

    OpenAIRE

    Sergey W. Kozlachkow

    2012-01-01

    The survey is concerned with the expansion joints, used in bridge constructions to compensate medium and significant operational linear and spatial displacements between adjacent spans or between bridge span and pier. The analysis of design features of these types of expansion joints, their advantages and disadvantages, based on operational experience justified the necessity to design constructions, meeting the modern demands imposed to expansion joints.

  16. Students design composite bridges

    NARCIS (Netherlands)

    Stark, J.W.B.; Galjaard, J.C.; Brekelmans, J.W.P.M.

    1999-01-01

    The paper gives an overview of recent research on steel-concrete composite bridge design by students of Delft University of Technology doing their master's thesis. Primary objective of this research was to find possibilities for application of steel-concrete composite bridges in the Netherlands,

  17. Bridge the Gap

    DEFF Research Database (Denmark)

    Marselis, Randi Lorenz

    2017-01-01

    This article focuses on photo projects organised for teenage refugees by the Society for Humanistic Photography (Berlin, Germany). These projects, named Bridge the Gap I (2015), and Bridge the Gap II (2016), were carried out in Berlin and brought together teenagers with refugee and German...

  18. Virtual Bridge Design Challenge

    Science.gov (United States)

    Mitts, Charles R.

    2013-01-01

    This design/problem-solving activity challenges students to design a replacement bridge for one that has been designated as either structurally deficient or functionally obsolete. The Aycock MS Technology/STEM Magnet Program Virtual Bridge Design Challenge is an authentic introduction to the engineering design process. It is a socially relevant…

  19. Linguistic Barriers and Bridges

    DEFF Research Database (Denmark)

    Thuesen, Frederik

    2016-01-01

    The influence of language on social capital in low-skill and ethnically diverse workplaces has thus far received very limited attention within the sociology of work. As the ethnically diverse workplace is an important social space for the construction of social relations bridging different social...... communication related to collaboration and ‘small talk’ may provide linguistic bridges to social capital formation....

  20. Vertical vibration control system for PC cable-stayed bridge during cantilever construction; Shuketa jogedo seishin sochi ni yoru haridashi sekoji no PC shachokyo no seishin

    Energy Technology Data Exchange (ETDEWEB)

    Oshio, M.; Nakano, R.; Niihara, Y.; Yano, K.; Takeda, T. [Kajima Corp., Tokyo (Japan)

    1995-12-20

    A PC cable-stayed bridge under extension construction having long span length may have long-cycle vibration generated because of wind. The vibration puts workers working on main girders into a state of seasick causing the workability to drop. Therefore, with an objective to reduce vibration occurring on the main girders during construction, discussions were given on application of an active type vertical vibration absorbing device. The vibration absorbing device is an active system that a weight is driven vertically by a hydraulic actuator. The device was developed with a target that damping ratio when a maximum extension is 120 m becomes three times that when no vibration is absorbed for a 5-span continuous PC cable-stayed bridge with a length of 675 m, a central span of 260 m, and a width of 11 m. A cage housing the weight is connected with the actuator at its top by using pins, and the weight is supported being suspended from the top of the actuator. Vibration is absorbed by utilizing reactive force generated when the weight is driven vertically by the hydraulic actuator. The hydraulic actuator contains a gas spring that supports the dead weight of the weight. Experiments have verified the effectiveness of the vertical vibration absorbing device. 4 refs., 12 figs., 3 tabs.

  1. Long Span Bridges in Scandinavia

    DEFF Research Database (Denmark)

    Gimsing, Niels Jørgen

    1998-01-01

    is found in Scandinavia - the 1210 m span of the Höga Kusten Bridge in Sweden.The Kvarnsund Bridge in Norway was at the completion in 1991 the longest cable-stayed bridge in the world, and the span of 530 m is still thge longest for cable-stayed bridges in concrete. The Øresund Bridge with its sapn of 490...... m is the longest among cable-stayed bridges for both road and railway traffic....

  2. Sustainable Bridge Infrastructure Procurement

    DEFF Research Database (Denmark)

    Safi, Mohammed; Du, Guangli; Simonsson, Peter

    2016-01-01

    The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use to p...... to procure the most “sustainable” (lifecycle-efficient) bridge through a fair design-build (D-B) tendering process, considering all the main aspects: life-cycle cost (LCC), service life-span, aesthetic demands and environmental impacts (LCA).......The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use...

  3. Wind tunnel test on PC cable-stayed bridge; PC shachokyo no taifu seino shiken

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Y. [Kyushu Inst. of Technology, Kitakyushu (Japan). Faculty of Engineering

    1997-05-30

    This paper describes the wind tunnel test on a PC cable-stayed bridge. The aerodynamic force that acts on a building is represented by the drag that works in the wind direction, the lift that works perpendicularly to the wind direction, and the aerodynamic moment that causes rotation. In the measurement of wind load, a girder is partially extracted in the wind tunnel and set in a three-component balance, and the drag, lift, and aerodynamic moment are measured using a strain meter while blowing the wind. In a wind tunnel experiment, the similarity on Reynolds number, field number, rigidity, hydraulic force, structural attenuation, and reduced wind velocity is required. However, the wind velocity in the actual bridge uses the same air as that in an experiment. The similarity rule on the Reynolds is not thus satisfied. It is necessary to cause no self-excited vibration (galloping and flutter) as wind-resistant performance and suppress the eddy excitation to less than the allowable amplitude. Moreover, the three-dimensional experiment using an elastic model is conducted in addition to the two-dimensional experiment using a rigid model. In the three-dimensional experiment, various vibration modes that occur in the actual bridge appear. 12 refs., 15 figs.

  4. Lessons from the light-cone box

    CERN Document Server

    Leibbrandt, G

    2000-01-01

    Working in the noncovariant light-cone gauge, we discuss the explicit computation of the 1PI four-point function ("box diagram") in Yang- Mills theory. The complete box diagram which consists of 16 box subdiagrams, 8 lynx subdiagrams and 4 fish subdiagrams, yields both local and nonlocal UV divergent terms. The nonlocal terms are consistent with gauge symmetry and correspond to a nonlocal renormalization of the wave function. (14 refs).

  5. Vertical gust response prediction of cable-stayed bridges in yawed wind; Shachokyo no shafu ni yoru enchoku gust oto no yosoku

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, S.; Nagamachi, K.; Kawai, Y. [Kawasaki Steel Corp., Tokyo (Japan); Kimura, K.; Fujino, Y. [The University of Tokyo, Tokyo (Japan). Faculty of Engineering; Tanaka, H.

    1996-03-01

    This paper outlines the vertical gust response analysis method in a yawed wind, gives an analytic example, and compares the experimental result with the analytic result to investigate the application of an analysis method and the validity of assumption and approximation. The vertical gust response to two cable-stayed bridges under construction in a yawed wind was predicted by applying assumption and approximation to the gust response prediction method in a yawed wind with the cantilever model having a plate cross-section manipulated. In this case, the wind velocity component perpendicular to the leading edge was defined as an effective wind velocity, and a bridge axis and the component perpendicular to a bridge axis were separately calculated in response. Moreover, some aerodynamic coefficients of a bridge girder cross-section were approximately obtained from the characteristics of the flat blades with same aspect ratio. The obtained analytic result was compared with the wind tunnel test result based on all bridge models. The result showed that the former almost coincides with the latter, the assumption and approximation of this time are verified in validity, and this analysis method can be used for cable-stayed bridges under construction. 10 refs., 7 figs., 2 tabs.

  6. IMPROVED, FAVORABLE FOR ENVIRONMENT POLYURETHANE COLD-BOX-PROCESS (COLD BOX «HUTTENES-ALBERTUS» .

    Directory of Open Access Journals (Sweden)

    A. Sergini

    2005-01-01

    Full Text Available The results of the laboratory and industrial investigations, the purpose of which is improvement of the classical Cold-box-process, i.e. the process of the slugs hardening in cold boxes, are presented.

  7. Automated analysis of long-term bridge behavior and health using a cyber-enabled wireless monitoring system

    Science.gov (United States)

    O'Connor, Sean M.; Zhang, Yilan; Lynch, Jerome; Ettouney, Mohammed; van der Linden, Gwen

    2014-04-01

    A worthy goal for the structural health monitoring field is the creation of a scalable monitoring system architecture that abstracts many of the system details (e.g., sensors, data) from the structure owner with the aim of providing "actionable" information that aids in their decision making process. While a broad array of sensor technologies have emerged, the ability for sensing systems to generate large amounts of data have far outpaced advances in data management and processing. To reverse this trend, this study explores the creation of a cyber-enabled wireless SHM system for highway bridges. The system is designed from the top down by considering the damage mechanisms of concern to bridge owners and then tailoring the sensing and decision support system around those concerns. The enabling element of the proposed system is a powerful data repository system termed SenStore. SenStore is designed to combine sensor data with bridge meta-data (e.g., geometric configuration, material properties, maintenance history, sensor locations, sensor types, inspection history). A wireless sensor network deployed to a bridge autonomously streams its measurement data to SenStore via a 3G cellular connection for storage. SenStore securely exposes the bridge meta- and sensor data to software clients that can process the data to extract information relevant to the decision making process of the bridge owner. To validate the proposed cyber-enable SHM system, the system is implemented on the Telegraph Road Bridge (Monroe, MI). The Telegraph Road Bridge is a traditional steel girder-concrete deck composite bridge located along a heavily travelled corridor in the Detroit metropolitan area. A permanent wireless sensor network has been installed to measure bridge accelerations, strains and temperatures. System identification and damage detection algorithms are created to automatically mine bridge response data stored in SenStore over an 18-month period. Tools like Gaussian Process (GP

  8. 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

  9. Sustainable Bridge Infrastructure Procurement

    DEFF Research Database (Denmark)

    Safi, Mohammed; Du, Guangli; Simonsson, Peter

    2016-01-01

    The lack of a flexible but systematic approach for integrating lifecycle aspects into bridge investment decisions is a major obstacle hindering the procurement of sustainable bridge infrastructures. This paper addresses this obstacle by introducing a holistic approach that agencies could use to p...... to procure the most “sustainable” (lifecycle-efficient) bridge through a fair design-build (D-B) tendering process, considering all the main aspects: life-cycle cost (LCC), service life-span, aesthetic demands and environmental impacts (LCA)....

  10. Non-intrusive schemes for speed and axle identification in bridge-weigh-in-motion systems

    Science.gov (United States)

    Kalhori, Hamed; Makki Alamdari, Mehrisadat; Zhu, Xinqun; Samali, Bijan; Mustapha, Samir

    2017-02-01

    Bridge weigh-in-motion (BWIM) is an approach through which the axle and gross weight of trucks travelling at normal highway speed are identified using the response of an instrumented bridge. The vehicle speed, the number of axles, and the axle spacing are crucial parameters, and are required to be determined in the majority of BWIM algorithms. Nothing-on-the-road (NOR) strategy suggests using the strain signals measured at some particular positions underneath the deck or girders of a bridge to obtain this information. The objective of this research is to present a concise overview of the challenges of the current non-intrusive schemes for speed and axle determination through bending-strain and shear-strain based approaches. The problem associated with the global bending-strain responses measured at quarter points of span is discussed and a new sensor arrangement is proposed as an alternative. As for measurement of local responses rather than the global responses, the advantage of shear strains over bending strains is presented. However, it is illustrated that shear strains at quarter points of span can only provide accurate speed estimation but fail to detect the correct number of axles. As a remedy, it is demonstrated that, even for closely-spaced axles, the shear strain at the beginning of the bridge is capable of reliably identifying the number of axles. In order to provide a fully automated speed and axle identification system, appropriate signal processing including low-pass filtering and wavelet transforms are applied to the raw time signals. As case studies, the results of experimental testing in laboratory and on a real bridge are presented.

  11. Investigation of Long-Term Prestress Losses in Pretensioned High Performance Concrete Girders

    OpenAIRE

    Cousins, Thomas E.

    2005-01-01

    Effective determination of long-term prestress losses is important in the design of prestressed concrete bridges. Over-predicting prestress losses results in an overly conservative design for service load stresses, and under-predicting prestress losses, can result in cracking at service loads. Creep and shrinkage produce the most significant time-dependent effect on prestress losses, and research has shown that high performance and high strength concretes (HPC and HSC) exhibit less creep and ...

  12. 36 CFR 1192.33 - Fare box.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Fare box. 1192.33 Section 1192.33 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD... Systems § 1192.33 Fare box. Where provided, the farebox shall be located as far forward as practicable and...

  13. Magnetorotational dynamo action in the shearing box

    Science.gov (United States)

    Walker, Justin; Boldyrev, Stanislav

    2017-09-01

    Magnetic dynamo action caused by the magnetorotational instability is studied in the shearing-box approximation with no imposed net magnetic flux. Consistent with recent studies, the dynamo action is found to be sensitive to the aspect ratio of the box: it is much easier to obtain in tall boxes (stretched in the direction normal to the disc plane) than in long boxes (stretched in the radial direction). Our direct numerical simulations indicate that the dynamo is possible in both cases, given a large enough magnetic Reynolds number. To explain the relatively larger effort required to obtain the dynamo action in a long box, we propose that the turbulent eddies caused by the instability most efficiently fold and mix the magnetic field lines in the radial direction. As a result, in the long box the scale of the generated strong azimuthal (stream-wise directed) magnetic field is always comparable to the scale of the turbulent eddies. In contrast, in the tall box the azimuthal magnetic flux spreads in the vertical direction over a distance exceeding the scale of the turbulent eddies. As a result, different vertical sections of the tall box are permeated by large-scale non-zero azimuthal magnetic fluxes, facilitating the instability. In agreement with this picture, the cases when the dynamo is efficient are characterized by a strong intermittency of the local azimuthal magnetic fluxes.

  14. Unification of box shapes in molecular simulations

    NARCIS (Netherlands)

    Bekker, H.

    1997-01-01

    In molecular simulations with periodic boundary conditions the computational box may have five different shapes: triclinic; the hexagonal prism; two types of dodecahedrons; and the truncated octahedron. In this article, we show that every molecular simulation, formulated in one of these boxes, can

  15. An effective box trap for capturing lynx

    Science.gov (United States)

    Jay A. Kolbe; John R. Squires; Thomas W. Parker

    2003-01-01

    We designed a box trap for capturing lynx (Lynx lynx) that is lightweight, safe, effective, and less expensive than many commercial models. It can be constructed in approximately 3-4 hours from readily available materials. We used this trap to capture 40 lynx 89 times (96% of lynx entering traps) and observed no trapping related injuries. We compare our box...

  16. Modern biotechnology Panacea or new Pandora's box?

    NARCIS (Netherlands)

    Tramper, J.; Yang Zhu, Yang

    2011-01-01

    According to Greek mythology Pandora was sent down to earth upon the orders of Zeus. She was given a mysterious box which she was not allowed to open. However, Pandora was very curious and when she arrived on earth she couldn?t help taking a peek inside the box. She saw that it was filled with gifts

  17. Cosmetic Foot Surgery: Fashion's Pandora's Box

    Science.gov (United States)

    ... Fashion’s Pandora’s Box? A A A | Print | Share Cosmetic Foot Surgery: Fashion’s Pandora’s Box? Foot and ankle ... extreme and imprudent as it may sound, the cosmetic surgery craze is not just for faces anymore— ...

  18. Box Plots in the Australian Curriculum

    Science.gov (United States)

    Watson, Jane M.

    2012-01-01

    This article compares the definition of "box plot" as used in the "Australian Curriculum: Mathematics" with other definitions used in the education community; describes the difficulties students experience when dealing with box plots; and discusses the elaboration that is necessary to enable teachers to develop the knowledge…

  19. 49 CFR 38.33 - Fare box.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 1 2010-10-01 2010-10-01 false Fare box. 38.33 Section 38.33 Transportation Office of the Secretary of Transportation AMERICANS WITH DISABILITIES ACT (ADA) ACCESSIBILITY SPECIFICATIONS FOR TRANSPORTATION VEHICLES Buses, Vans and Systems § 38.33 Fare box. Where provided, the farebox...

  20. The Cultural Bridge Model.

    Science.gov (United States)

    West, Edith A.

    1993-01-01

    Offers a cultural bridge model that would enhance the health care of the American Indian population. Suggests that transcultural nursing should transcend the realm of thought and become an integrated part of daily practice. (Author)

  1. 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...

  2. State's First Bridge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Article with details on the state's first bridge that crossed the Noxubee River adjacent to the Noxubee National Wildlife Refuge Boundary. Details also included...

  3. North American box turtles: A natural history

    Science.gov (United States)

    Dodd, C. Kenneth

    2002-01-01

    Once a familiar backyard visitor in many parts of the United States and Mexico, the box turtle is losing the battle against extinction. In North American Box Turtles, C. Kenneth Dodd, Jr., has written the first book-length natural history of the twelve species and subspecies of this endangered animal. This volume includes comprehensive information on the species’ evolution, behavior, courtship and reproduction, habitat use, diet, population structure, systematics, and disease. Special features include color photos of all species, subspecies, and their habitats; a simple identification guide to both living and fossil species; and a summary of information on fossil Terrapene and Native uses of box turtles. End-of-chapter sections highlight future research directions, including the need for long-term monitoring and observation of box turtles within their natural habitat and conservation applications. A glossary and a bibliography of literature on box turtles accompany the text.

  4. Forward Affect Bridge.

    Science.gov (United States)

    Bonshtein, Udi; Torem, Moshe

    2017-01-01

    This article presents a modification of the affect bridge technique. The Forward Affect Bridge enables practitioners to create and maintain hope when it is missing. Hope is relevant for diminishing avoidance and being involved with necessary activities. The main idea is to build up a positive atmosphere in the here and now (relying on rapport), to amplify it, and to project it forward. By using clinical vignettes, the authors illustrate these techniques.

  5. Bridges Expansion Joints

    Directory of Open Access Journals (Sweden)

    Sergey W. Kozlachkow

    2012-05-01

    Full Text Available The survey is concerned with the expansion joints, used in bridge constructions to compensate medium and significant operational linear and spatial displacements between adjacent spans or between bridge span and pier. The analysis of design features of these types of expansion joints, their advantages and disadvantages, based on operational experience justified the necessity to design constructions, meeting the modern demands imposed to expansion joints.

  6. Linear and Non-linear Analysis of Fibre Reinforced Plastic Bridge Deck due to Vehicle Loads

    Science.gov (United States)

    Ray, Chaitali; Mandal, Bibekananda

    2015-06-01

    The present work deals with linear and nonlinear static analysis of fibre reinforced plastics composite bridge deck structures using the finite element method. The nonlinear static analysis has been carried out considering geometric nonlinearity. The analysis of bridge deck has been carried out under vehicle load as specified by IRC Class B wheel load classification. The formulation has been carried out using the finite element software package ANSYS 14.0 and the SHELL281 element is used to model the bridge deck. The bridge deck has also been modeled as a plate stiffened with closely spaced hollow box sections and a computer code is developed based on this formulation. The results obtained from the present formulation are compared with those available in the published literature. A parametric study on the stiffened bridge deck has also been carried out with varying dimensions of the stiffeners under vehicle loads.

  7. Author Details

    African Journals Online (AJOL)

    Osadebe, NN. Vol 31, No 3 (2012) - Articles Technical Note: Effect of Incorporating Expanded Polystyrene Aggregate Granules in Concrete Matrix Abstract PDF · Vol 33, No 4 (2014) - Research papers. Stress Distribution in Continuous Thin-Walled Multi-Cell Box Girder Bridges Abstract PDF · Vol 34, No 3 (2015) - Building, ...

  8. numerical and numerical and experimental modeling of the static

    African Journals Online (AJOL)

    eobe

    recommendation for subsequent experiments and analysis of these types of structural elements. In this paper a report of numerical and experimental modeling of the static response of thin-walled reinforced concrete box girder bridges is given. The work is executed to verify the validity of a software developed by the authors ...

  9. Tsunamis: bridging science, engineering and society.

    Science.gov (United States)

    Kânoğlu, U; Titov, V; Bernard, E; Synolakis, C

    2015-10-28

    Tsunamis are high-impact, long-duration disasters that in most cases allow for only minutes of warning before impact. Since the 2004 Boxing Day tsunami, there have been significant advancements in warning methodology, pre-disaster preparedness and basic understanding of related phenomena. Yet, the trail of destruction of the 2011 Japan tsunami, broadcast live to a stunned world audience, underscored the difficulties of implementing advances in applied hazard mitigation. We describe state of the art methodologies, standards for warnings and summarize recent advances in basic understanding, and identify cross-disciplinary challenges. The stage is set to bridge science, engineering and society to help build up coastal resilience and reduce losses. © 2015 The Author(s).

  10. Hydro-Balanced Stuffing Box field test

    Energy Technology Data Exchange (ETDEWEB)

    Giangiacomo, L.A.

    1999-05-28

    The Hydro-Balanced Stuffing Box is a seal assembly for polished rod pumping installations commonly used in oil and gas pumping well installations to contain produced well fluids. The improved stuffing box was developed and patented by Harold H. Palmour of The Palmour Group of Livingston, TX. The stuffing box is designed to reduce the incidence of seal leakage and to utilize an environmentally safe fluid, so that if there is any leakage, environmental damage is reduced or eliminated. The unit was tested on two wells at the Rocky Mountain Oilfield Testing Center. During the test period, the performance of the stuffing box was measured by monitoring the pressure on the tubing and the inner chamber with a Barton Two-pen recorder. The amount of safe fluid consumed, fluid leakage at the top of the stuffing box, pressure supplied from the nitrogen bottle, ambient temperature, and polish rod temperature was recorded. The stuffing box is capable of providing a better seal between well fluids an d the environment than conventional stuffing boxes. It allows the polished rod to operate cooler and with lubrication, extending the life of the packing elements, and reducing the amount of attention required to prevent leakage.

  11. 47 CFR 80.1007 - Bridge-to-bridge radiotelephone installation.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Bridge-to-bridge radiotelephone installation. 80.1007 Section 80.1007 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND... Bridge-to-Bridge Act § 80.1007 Bridge-to-bridge radiotelephone installation. Use of the bridge-to-bridge...

  12. 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.

  13. Bridging the Gap

    DEFF Research Database (Denmark)

    Dahlberg, Rasmus

    2016-01-01

    The fixed link between Denmark and Sweden connects two busy cities and a large international airport with many of its travelers and employees. 18,000 vehicles and 160 passenger trains transport each day more than 70,000 people across the combined road and rail Øresund Bridge and through the Øresund...... Tunnel, approximately 25,000 of them critical to the regional work market. Even though the risk analysis states that the likelihood of a long-term closure (100C days) is very low Danish and Swedish transport authorities have demanded that the infrastructure operator conducts a survey of the preparedness...... in its final report to the Danish and Swedish transport authorities while drawing upon experiences from two recent comparable cases of infrastructure disruptions: The Champlain Bridge (2009) and the Forth Road Bridge (2015)....

  14. [Present views on boxing--Henner's legacy].

    Science.gov (United States)

    Tichý, J

    1997-05-29

    Fifty years ago academician Henner formulated clearly the negative view of neurologists on boxing as practised in his time. It was his merit that a protective helmet was introduced, many of his demands concerning the regime after a KO and the importance of medical examinations were no yet adequately appreciated. At the opportunity of the 100th anniversary of Henner's birth and the fiftieth anniversary of the Clinic he founded in the premises of saint Catherine the author discusses contemporary views on boxing, the risk of repeated injuries for the development of encephalopathia pugilistica and their relationship to Alzheimer's disease. Contemporary boxing is a spectacle which is a continuation of historical fights of gladiators. If the main objective is to hurt the adversary, this activity does not deserve the name of "sport" Sport should promote and maintain physical and mental health which is not the case in professional boxing.

  15. Grey Box Modelling of Hydrological Systems

    DEFF Research Database (Denmark)

    Thordarson, Fannar Ørn

    The main topic of the thesis is grey box modelling of hydrologic systems, as well as formulation and assessment of their embedded uncertainties. Grey box model is a combination of a white box model, a physically-based model that is traditionally formulated using deterministic ordinary differential...... represent a stochastic state space model. In the grey box model the total noise is divided into a measurement noise and a process noise. The process noise is due to model approximations, undiscovered input and uncertainties in the input series. Estimates of the process noise can be used to highlight...... in the model, or formulation of process noise can be considered so that it meets the physical limits of the hydrological system and give an adequate description of the embedded uncertainty in model structure. The thesis consists of two parts: a summary report and a part which contains six scientific papers...

  16. Black-Box Search by Unbiased Variation

    DEFF Research Database (Denmark)

    Lehre, Per Kristian; Witt, Carsten

    2012-01-01

    The complexity theory for black-box algorithms, introduced by Droste, Jansen, and Wegener (Theory Comput. Syst. 39:525–544, 2006), describes common limits on the efficiency of a broad class of randomised search heuristics. There is an obvious trade-off between the generality of the black-box model...... and the strength of the bounds that can be proven in such a model. In particular, the original black-box model provides for well-known benchmark problems relatively small lower bounds, which seem unrealistic in certain cases and are typically not met by popular search heuristics.In this paper, we introduce a more...... restricted black-box model for optimisation of pseudo-Boolean functions which we claim captures the working principles of many randomised search heuristics including simulated annealing, evolutionary algorithms, randomised local search, and others. The key concept worked out is an unbiased variation operator...

  17. EPA EcoBox Tools by Stressors

    Science.gov (United States)

    Eco-Box is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

  18. Packing a cake into a box

    KAUST Repository

    Skopenkov, Mikhail

    2011-05-01

    Given a triangular cake and a box in the shape of its mirror image, how can the cake be cut into a minimal number of pieces so that it can be put into the box? The cake has icing, so we are not allowed to put it into the box upside down. V. G. Boltyansky asked this question in 1977 and showed that three pieces always suffice. In this paper we provide examples of cakes that cannot be cut into two pieces to be put into the box. This shows that three is the answer to Boltyansky\\'s question. We also give examples of cakes which can be cut into two pieces. © THE MATHEMATICAL ASSOCIATION OF AMERICA.

  19. ENERGY STAR Certified Set Top Boxes

    Data.gov (United States)

    U.S. Environmental Protection Agency — Certified models meet all ENERGY STAR requirements as listed in the Version 5.1 ENERGY STAR Program Requirements for Set-top Boxes that are effective as of January...

  20. A Lithium Vapor Box Divertor Similarity Experiment

    Science.gov (United States)

    Cohen, Robert A.; Emdee, Eric D.; Goldston, Robert J.; Jaworski, Michael A.; Schwartz, Jacob A.

    2017-10-01

    A lithium vapor box divertor offers an alternate means of managing the extreme power density of divertor plasmas by leveraging gaseous lithium to volumetrically extract power. The vapor box divertor is a baffled slot with liquid lithium coated walls held at temperatures which increase toward the divertor floor. The resulting vapor pressure differential drives gaseous lithium from hotter chambers into cooler ones, where the lithium condenses and returns. A similarity experiment was devised to investigate the advantages offered by a vapor box divertor design. We discuss the design, construction, and early findings of the vapor box divertor experiment including vapor can construction, power transfer calculations, joint integrity tests, and thermocouple data logging. Heat redistribution of an incident plasma-based heat flux from a typical linear plasma device is also presented. This work supported by DOE Contract No. DE-AC02-09CH11466 and The Princeton Environmental Institute.

  1. Tracking the Motion of Box Jellyfish

    OpenAIRE

    Kjellberg, Tobias; Palmér, Tobias; Oskarsson, Magnus; Åström, Karl

    2014-01-01

    In this paper we investigate a system for tracking the motion of box jellyfish tripedalia cystophora in a special test setup. The goal is to measure the motor response of the animal given certain visual stimuli. The approach is based on tracking the special sensory structures – the rhopalia – of the box jellyfish from high-speed video sequences. We have focused on a realtime system with simple building blocks in our system. However, using a combination of simple intensity...

  2. Box Lesion with Single Radiofrequency Clamp.

    Science.gov (United States)

    Shaikhrezai, Kasra; Spadaccio, Cristiano; Hunter, Steven

    2017-04-12

    We introduce a maneuver to perform the box lesion as a part of Cox maze IV procedure with single radiofrequency clamp. The maneuver entails engaging the right pulmonary veins with the clamp, then advancing the clamp jaws underneath the superior vena cava through the transverse sinus to include the roof and the left pulmonary veins in the clamp. We regularly use this technique for box lesion with desirable transmurality. Georg Thieme Verlag KG Stuttgart · New York.

  3. Autoantibodies to box A of high mobility group box 1 in systemic lupus erythematosus.

    Science.gov (United States)

    Schaper, F; de Leeuw, K; Horst, G; Maas, F; Bootsma, H; Heeringa, P; Limburg, P C; Westra, J

    2017-06-01

    Autoantibodies to nuclear structures are a hallmark of systemic lupus erythematosus (SLE), including autoantibodies to nuclear protein high mobility group box 1 (HMGB1). HMGB1 consists of three separate domains: box A, box B and an acidic tail. Recombinant box A acts as a competitive antagonist for HMGB1 and might be an interesting treatment option in SLE. However, antibodies to box A might interfere. Therefore, levels of anti-box A were examined in SLE patients in association with disease activity and clinical parameters. Serum anti-box A was measured in 86 SLE patients and 44 age- and sex-matched healthy controls (HC). Serum samples of 28 patients with primary Sjögren's syndrome and 32 patients with rheumatoid arthritis were included as disease controls. Anti-HMGB1 and anti-box B levels were also measured by enzyme-linked immunosorbent assay during quiescent disease [SLE Disease Activity Index (SLEDAI) ≤ 4, n = 47] and active disease (SLEDAI ≥ 5, n = 39). Anti-box A levels in active SLE patients were higher compared to quiescent patients, and were increased significantly compared to HC and disease controls. Anti-box A levels correlated positively with SLEDAI and anti-dsDNA levels and negatively with complement C3 levels. Increased levels of anti-box A antibodies were present in the majority of patients with nephritic (73%) and non-nephritic exacerbations (71%). Antibodies to the box A domain of HMGB1 might be an interesting new biomarker, as these had a high specificity for SLE and were associated with disease activity. Longitudinal studies should be performed to evaluate whether these antibodies perform better in predicting an exacerbation, especially non-nephritic exacerbations. © 2017 British Society for Immunology.

  4. HYDROGEN AND VOC RETENTION IN WASTE BOXES

    Energy Technology Data Exchange (ETDEWEB)

    PACE ME; MARUSICH RM

    2008-11-21

    The Hanford Waste Management Project Master Documented Safety Analysis (MDSA) (HNF-14741, 2003) identifies derived safety controls to prevent or mitigate the risks of a single-container deflagration during operations requiring moving, venting or opening transuranic (TRU)-waste containers. The issue is whether these safety controls are necessary for operations involving TRU-waste boxes that are being retrieved from burial at the Hanford Site. This paper investigates the potential for a deflagration hazard within these boxes and whether safety controls identified for drum deflagration hazards should be applied to operations involving these boxes. The study evaluates the accumulation of hydrogen and VOCs within the waste box and the transport of these gases and vapors out of the waste box. To perform the analysis, there were numerous and major assumptions made regarding the generation rate and the transport pathway dimensions and their number. Since there is little actual data with regards to these assumptions, analyses of three potential configurations were performed to obtain some indication of the bounds of the issue (the concentration of hydrogen or flammable VOCs within a waste box). A brief description of each of the three cases along with the results of the analysis is summarized.

  5. Box-Cox transformation for QTL mapping.

    Science.gov (United States)

    Yang, Runqing; Yi, Nengjun; Xu, Shizhong

    2006-01-01

    The maximum likelihood method of QTL mapping assumes that the phenotypic values of a quantitative trait follow a normal distribution. If the assumption is violated, some forms of transformation should be taken to make the assumption approximately true. The Box-Cox transformation is a general transformation method which can be applied to many different types of data. The flexibility of the Box-Cox transformation is due to a variable, called transformation factor, appearing in the Box-Cox formula. We developed a maximum likelihood method that treats the transformation factor as an unknown parameter, which is estimated from the data simultaneously along with the QTL parameters. The method makes an objective choice of data transformation and thus can be applied to QTL analysis for many different types of data. Simulation studies show that (1) Box-Cox transformation can substantially increase the power of QTL detection; (2) Box-Cox transformation can replace some specialized transformation methods that are commonly used in QTL mapping; and (3) applying the Box-Cox transformation to data already normally distributed does not harm the result.

  6. Ultra-high performance fiber-reinforced concrete (UHPFRC) for infrastructure rehabilitation : volume 1 : evaluation of ultra high strength concrete (UHSC) in joints of bridge girders.

    Science.gov (United States)

    2017-03-01

    Joints are often considered as the weak link in a structure and often deterioration of the structure initiates from the : joints. Joints transfer the stresses from super-structure to sub-structure and in this process are subjected to large : transfer...

  7. Bridge-Vehicle Impact Assessment

    Science.gov (United States)

    2011-08-01

    Bridges in New York State have been experiencing close to 200 bridge hits a year. These : accidents are attributed to numerous factors including: improperly stored equipment on trucks; : violation of vehicle posting signs; illegal commercial vehicles...

  8. Existing Steel Railway Bridges Evaluation

    Directory of Open Access Journals (Sweden)

    Vičan Josef

    2016-12-01

    Full Text Available The article describes general principles and basis of evaluation of existing railway bridges based on the concept of load-carrying capacity determination. Compared to the design of a new bridge, the modified reliability level for existing bridges evaluation should be considered due to implementation of the additional data related to bridge condition and behaviour obtained from regular inspections. Based on those data respecting the bridge remaining lifetime, a modification of partial safety factors for actions and materials could be respected in the bridge evaluation process. A great attention is also paid to the specific problems of determination of load-caring capacity of steel railway bridges in service. Recommendation for global analysis and methodology for existing steel bridge superstructure load-carrying capacity determination are described too.

  9. Colorado statewide historic bridge inventory.

    Science.gov (United States)

    2011-05-01

    The purpose of the Colorado statewide historic bridge inventory was to document and evaluate the National : Register of Historic Places eligibility all on-system highway bridges and grade separation structures built in : Colorado between 1959 and 196...

  10. Strengthening bridges using composite materials.

    Science.gov (United States)

    1998-03-01

    The objective of this research project is to outline methodologies for using Fiber Reinforced Polymer (FRP) composites to strengthen and rehabilitate reinforced concrete bridge elements. : Infrastructure deterioration and bridge strengthening techniq...

  11. Virginia Bridge Information Systems Laboratory.

    Science.gov (United States)

    2014-06-01

    This report presents the results of applied data mining of legacy bridge databases, focusing on the Pontis and : National Bridge Inventory databases maintained by the Virginia Department of Transportation (VDOT). Data : analysis was performed using a...

  12. Uncontrolled concrete bridge parapet cracking.

    Science.gov (United States)

    2013-06-01

    The Ohio Department of Transportation has recently identified the problem of wide-spread premature cracking of concrete bridge : parapets throughout its District 12 region (Northeast Ohio). Many of the bridge decks that contain these prematurely crac...

  13. Assessing Static Performance of the Dashengguan Yangtze Bridge by Monitoring the Correlation between Temperature Field and Its Static Strains

    Directory of Open Access Journals (Sweden)

    Gao-Xin Wang

    2015-01-01

    Full Text Available Taking advantage of the structural health monitoring system installed on the steel truss arch girder of Dashengguan Yangtze Bridge, the temperature field data and static strain data are collected and analyzed for the static performance assessment of the bridge. Through analysis, it is found that the static strain changes are mainly caused by temperature field (temperature and temperature difference and train. After the train-induced static strains are removed, the correlation between the remaining static strains and the temperature field shows apparent linear characteristics, which can be mathematically modeled for the description of static performance. Therefore, multivariate linear regression function combined with principal component analysis is introduced to mathematically model the correlation. Furthermore, the residual static strains of mathematical model are adopted as assessment indicator and three kinds of degradation regulations of static performance are obtained after simulation of the residual static strains. Finally, it is concluded that the static performance of Dashengguan Yangtze Bridge was in a good condition during that period.

  14. Building a Straw Bridge

    Science.gov (United States)

    Teaching Science, 2015

    2015-01-01

    This project is for a team of students (groups of two or three are ideal) to design and construct a model of a single-span bridge, using plastic drinking straws as the building material. All steps of the design, construction, testing and critiquing stages should be recorded by students in a journal. Students may like to include labelled diagrams,…

  15. Bridge the Gap.

    Science.gov (United States)

    Klein, Mel; Cufaude, Jeffrey B.

    1989-01-01

    This document consists of two paired articles: the first, "Preparing Faculty Out of Class Experiences," by Mel Klein, and the second, "Help Advisers Be More Than Ghost Signatures," by Jeffrey B. Calfaude. Each article shares insights on how faculty advisers "bridge the gap" between students and faculty. When faculty members are asked to advise…

  16. Bridging the gap

    Science.gov (United States)

    2012-08-01

    Astronomy is flourishing in China, with impressive achievements in instrument design and construction matched by a higher international research profile. Yet there remains a mismatch between the facilities available and those needed to progress. Sue Bowler wonders how the country will bridge the gap.

  17. Quantum Bidding in Bridge

    Directory of Open Access Journals (Sweden)

    Sadiq Muhammad

    2014-06-01

    Full Text Available 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.

  18. 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...

  19. Bridging the Gap?

    Science.gov (United States)

    Salter, Colin

    2009-01-01

    The political context of the conversion of the Historic Tramway Bridge, adjacent to Sandon Point in Bulli (NSW, Australia), and how this was exploited to serve predetermined ends, illustrates that technologies can be designed to have particular social (and political) effects. Through reflection on this relatively small engineering project, this…

  20. 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....