Elastoplastic Seismic Response Analysis Of The High-speed Railway Bridges

With the rapid development of high-speed railway in China and abroad, for the good smoothness and stability of line and overpass and saving land resources, the viaduct bridge which extend from tens to hundreds of kilometers be build in the high-speed railway, the probability which the vehicle travel on the viaduct bridge will be greatly increase; at the same time, the mass and stiffness of boxing girder and pier of high-speed railway bridge is of greater than common railway bridge, the seismic responses of bridge under earthquake is of greater than the common railway bridge, the seismic force will play a crucial role in design of high-speed railway bridge. Much of ductility experiments of bridge mainly aimed at the pier of the road bridge, the existing theory analysis of vehicle-bridge reaction focus on elasticity stage. The research on the elasto-plastic analysis of high-speed railway bridge which has the low ratio of reinforcement and axial compression ratio is little, so the study on the dynamic responses of high-speed railway bridge under earthquake is of great significanceFirstly, the paper introduces the vehicle-bridge coupled vibration and vehicle-bridge coupled vibration under earthquake at home and abroad. The following work has been mainly done:the selection and simplification of vehicle model, the determining of vehicle parameters and the time domain vertical profile irregularity specimen, the stiffness matrix of the bridge, the determining of the restoring force model, the establishment of the equation of the whole vehicle-bridge under earthquake, the numerical solution method of the whole vehicle-bridge under earthquake is presented.Secondly, ANSYS software is used to establish the whole vehicle-bridge system under the earthquake, analyze the elastic seismic responses of the vehicle-bridge system, the influence of the different parameter such as different vehicle speed, pier height and earthquake wave is studied in the paper, because many high-speed railway line pass through soft foundation soil, the model of pier bottom which is solidificated and the model which consider the pile-soil interaction are established in the paper, the influence of the pile-soil interaction to the seismic response of the bridge should be considered, some constructive conclusions and suggestions are presented from the analysis resultsAt last, the elasto-plastic seismic analysis of high-speed railway bridge pier is conducted in this paper, by means of moment-curvature relationship program, the bending moment and curvature are calculated, based on MATLAB soft ware, the model of high-speed railway bridge pier under high-level earthquake is set up, elasto-plastic seismic analysis program is compiled, the elastic-plastic deformation of pier are calculated, the influence of high-level earthquake is analyzed in the paper.