scholarly journals The Seismic Response of High-Speed Railway Bridges Subjected to Near-Fault Forward Directivity Ground Motions Using a Vehicle-Track-Bridge Element

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Chen Ling-kun ◽  
Jiang Li-zhong ◽  
Guo Wei ◽  
Liu Wen-shuo ◽  
Zeng Zhi-ping ◽  
...  
Keyword(s):  
High Speed ◽  
Ground Motions ◽  
Element Model ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
High Speed Railway ◽  
Near Fault ◽  
Pulse Effect ◽  
Short Period ◽  
Track Bridge

Based on the Next Generation Attenuation (NGA) project ground motion library, the finite element model of the high-speed railway vehicle-bridge system is established. The model was specifically developed for such system that is subjected to near-fault ground motions. In addition, it accounted for the influence of the rail irregularities. The vehicle-track-bridge (VTB) element is presented to simulate the interaction between train and bridge, in which a train can be modeled as a series of sprung masses concentrated at the axle positions. For the short period railway bridge, the results from the case study demonstrate that directivity pulse effect tends to increase the seismic responses of the bridge compared with far-fault ground motions or nonpulse-like motions and the directivity pulse effect and high values of the vertical acceleration component can notably influence the hysteretic behaviour of piers.

scholarly journals The Influence of an Integration Time Step on Dynamic Calculation of a Vehicle-Track-Bridge under High-Speed Railway

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 431
Author(s):  
Junjie Ye ◽  
Hao Sun
Keyword(s):  
High Speed ◽  
Coupled Model ◽  
Short Wave ◽  
Integration Time ◽  
Vertical Acceleration ◽  
Dynamic Calculation ◽  
Time Step ◽  
High Speed Railway ◽  
Track Irregularity ◽  
Track Bridge

In order to study the influence of an integration time step on dynamic calculation of a vehicle-track-bridge under high-speed railway, a vehicle-track-bridge (VTB) coupled model is established. The influence of the integration time step on calculation accuracy and calculation stability under different speeds or different track regularity states is studied. The influence of the track irregularity on the integration time step is further analyzed by using the spectral characteristic of sensitive wavelength. According to the results, the disparity among the effect of the integration time step on the calculation accuracy of the VTB coupled model at different speeds is very small. Higher speed requires a smaller integration time step to keep the calculation results stable. The effect of the integration time step on the calculation stability of the maximum vertical acceleration of each component at different speeds is somewhat different, and the mechanism of the effect of the integration time step on the calculation stability of the vehicle-track-bridge coupled system is that corresponding displacement at the integration time step is different. The calculation deviation of the maximum vertical acceleration of the car body, wheel-sets and bridge under the track short wave irregularity state are greatly increased compared with that without track irregularity. The maximum vertical acceleration of wheel-sets, rails, track slabs and the bridge under the track short wave irregularity state all show a significant declining trend. The larger the vibration frequency is, the smaller the range of integration time step is for dynamic calculation.

scholarly journals Effect of Bridge-Pier Differential Settlement on the Dynamic Response of a High-Speed Railway Train-Track-Bridge System

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaohui Zhang ◽  
Yao Shan ◽  
Xinwen Yang
Keyword(s):  
Dynamic Response ◽  
High Speed ◽  
Tensile Force ◽  
Differential Settlement ◽  
Bridge Pier ◽  
Vertical Acceleration ◽  
Train Track ◽  
Allowable Limit ◽  
High Speed Railway ◽  
Track Bridge

A model based on the theory of train-track-bridge coupling dynamics is built in the article to investigate how high-speed railway bridge pier differential settlement can affect various railway performance-related criteria. The performance of the model compares favorably with that of a 3D finite element model and train-track-bridge numerical model. The analysis of the study demonstrates that all the dynamic response for a span of 24 m is slightly larger than that for a span of 32 m. The wheel unloading rate increases with pier differential settlement for all of the calculation conditions considered, and its maximum value of 0.695 is well below the allowable limit. Meanwhile, the vertical acceleration increases with pier differential settlement and train speed, respectively, and the values for a pier differential settlement of 10 mm and speed of 350 km/h exceed the maximum allowable limit stipulated in the Chinese standards. On this basis, a speed limit for the exceeding pier differential settlement is determined for comfort consideration. Fasteners that had an initial tensile force due to pier differential settlement experience both compressive and tensile forces as the train passes through and are likely to have a lower service life than those which solely experience compressive forces.

Study of Bridge Piers Lateral Stiffness in Railway Vehicle-Bridge System

2014 ◽  
Vol 1025-1026 ◽  
pp. 868-871
Author(s):  
Jia Yu Yuan ◽  
Zhi Ping Zeng ◽  
Can Liu ◽  
Xian Feng He ◽  
Kun Teng Zhu
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
System Analysis ◽  
Element Model ◽  
Railway Vehicle ◽  
Lateral Stiffness ◽  
Coupled Vibration ◽  
High Speed Railway ◽  
Bridge Model

With the high-speed railway construction, studying of the vehicle-bridge vibration system increasingly important. This article established a range of high-speed trains linear model and standard high-speed railway 32 m span bridge model then a combination of both established based on ANSYS vehicle-bridge finite element model. Followed based on ANSYS high-speed train-bridge Coupled Vibration Simulation Analysis System. Analysis of a variety mound lateral stiffness, According to the analysis results of the piers of the basic principles. The bridge has been established based on the finite element model. Respectively, from the height of piers and pier-shaped two aspects to computational analysis the piers for bridge Coupled Vibration of Dynamic Response of Bridges. Provide a reference for the design of high-speed railway.

Effects of Pier Deformation on Train Operations within High-Speed Railway Ballastless Track–Bridge Systems

2018 ◽  
Vol 2672 (10) ◽  
pp. 96-105 ◽  
Author(s):  
De Zhang ◽  
Junhua Xiao ◽  
Xiao Zhang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Element Model ◽  
Lateral Deformation ◽  
Train Track ◽  
High Speed Railway ◽  
Ballastless Track ◽  
Train Operation ◽  
Track Bridge

The deformation of a bridge foundation (i.e. pier) for a ballastless track of a high-speed railway may cause additional irregularities within the track, thereby affecting train operation. By using a unit slab ballastless track bridge system as the research object, this study built a finite element model and a train–track dynamic interaction model. The additional rail deformation caused by the vertical or lateral deformation of a bridge pier was calculated by the finite element model, and then the effects on train operation due to the additional rail deformation were analyzed by the train–track dynamic model. It was found that the lateral deformation of a single pier should be of the most concern for the management and control of a high-speed railway. Specifically, when a pier suffered settlement and lateral deformation concurrently, the evaluation indices of train operation were primarily affected by the magnitude of the lateral deformation, and were only slightly affected by the settlement.

The Vertical and Horizontal Spectra of Near-Fault Ground Motions

2012 ◽  
Vol 204-208 ◽  
pp. 3335-3339
Author(s):  
Jiang Yin ◽  
Xian Yan Zhou ◽  
Guo Jing He
Keyword(s):  
Ground Motions ◽  
Response Spectra ◽  
Vertical Acceleration ◽  
Period Range ◽  
Seismic Reliability ◽  
Design Spectrum ◽  
Near Fault ◽  
Seismic Design Code ◽  
Short Period ◽  
Near Fault Earthquakes

Based on the horizontal and vertical components of a set of 30 acceleration records obtained from 10 near-fault earthquakes, the horizontal and the vertical response spectra are established, and have been compared with each other in this study. Statistical analyses show that, for the selected 30 acceleration records, the maximum mean of vertical acceleration spectra is slightly higher than which of horizontal acceleration spectra. That means the near-fault earthquake really have significant vertical effect. Consulting the domestic and international research achievement, the normalized near-fault design spectrum adapted to Chinese seismic design Code (GB50011-2010) is established in horizontal direction. The results show that, within short period range, the horizontal near-fault design spectrum obtained in this paper is obviously higher than which derived from Chinese seismic code. Subsequently, the spectra of horizontal components for the selected 30 records are each scaled to match the horizontal near-fault design spectrum at two periodic points of 1.0 and 1.5 sec respectively, and the corresponding vertical spectra are scaled with the horizontal spectra at the same time. The scaled results reveal that the vertical spectra have much higher discretion than horizontal spectra, hence the study in this paper could initiates the research interest to a new aspect concerned with the randomness of vertical spectra for near-fault ground motions, which would affect the seismic reliability of structures significantly.

Additional Longitudinal Expansion Force between Continuous Welded Rails and Extra-Long Continuous Bridges of High-Speed Railway

2012 ◽  
Vol 178-181 ◽  
pp. 2304-2307
Author(s):  
Wen Shuo Liu ◽  
Gong Lian Dai
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Element Model ◽  
High Speed Railway ◽  
Long Span ◽  
Spring Element ◽  
Longitudinal Stiffness ◽  
Longitudinal Resistance ◽  
Expansion Force ◽  
Track Bridge

In order to investigate the additional expansion force of continuous welded rails (CWR) on extra-long continuous bridges of high-speed railways, the integrative spatial finite element model of track-bridge-pier system is established with the nonlinear spring element simulating the longitudinal resistance between track and bridge. In this paper, the influences of several parameters to the additional expansion force of CWR are studied, including the different resistance models, the number of main spans, the arrangement of adjacent bridges as well as the pier’s longitudinal stiffness. Some conclusions are drawn through comparisons and analysis, which could provide valuable references for design and application of long-span continuous bridges on high-speed railways.

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