Influence Of Reinforcement Ratio On Seismic Response Of Round-ended Bridge Piers In High Speed Railway

Bridge is an important part of the high speed railway. And bridge piers play crucial roles in resisting lateral force under earthquake motion. Although a lot of successful experience in high speed railway construction has been accumulated, systematic theory and test researches on the key problems of the high speed railway piers with low ratio of reinforcement, such as seismic performance and design method, are still deficent. Considering the lack of seismic researches of high speed railway piers, this article is focused on the round-ended bridge piers in high speed railway. The principle contents are as follows:(1) A high speed railway round-ended bridge pier model, which was designed according to the dynamic similitude laws, was tested on the shaking table with both unidirectional and bidirectional horizontal earthquake motion. Test results indicate that the model has good seismic performance under the earthquake loading conditions and the section stiffness weakens slightly. The pier-top acceleration and displacement amplitude under the unidirectional horizontal seismic motion differ little from those in the corresponding direction under the bidirectional horizontal seismic motion.(2) Using ABAQUS and choosing proper constitutive relation of concrete and reinforcement, simulation model of round-ended pier in shake table test was modeled and nonlinear time history analysis was done. The experimental and calculated results are in good accordance, demonstrating the reliability and accuracy of the calculation conducted by the finite element analysis software.(3) Considering two parameters, longitudinal reinforcement ratio and stirrup ratio, a set of round-ended piers,10piers in all, was designed. With ABAQUS, nonlinear time history analysis was done under bidirectional horizontal seismic influence. By thoroughly analyzing the influence on the acceleration response, displacement response, shear force in bottom, equivalent plastic strain, energy dissipation, ductility, etc caused by these two parameters, some suggestions are concluded for seismic design of round-ended piers in high speed railway.