IMPACT EFFECTS ANALYSIS of SIMPLE-SUPPORTED BRIDGES UNDER EARTHQUAKE

摘要

The seismic pounding damages of bridges occurred under several earthquakes, so the research on pounding effects and countermeasures for mitigation of bridges is needed considering the fact that many girder bridges with high piers are being built in China. This paper proposes a nonlinear pounding model simulating both the pounding effects among girders and the role of isolators below. The finite element model of a bridge is formed, and the seismic pounding effects on bridge are analyzed under different ground motions, then the countermeasures are offered. The results show that the nonlinear pounding model presented in the paper can reasonably simulate the seismic pounding that has complex effects on the seismic response of bridge. It's also found that the characteristics of ground motions influence the pounding effects of structure markedly, and that adjusting the stiffness of isolators and the width of expansion joint properly can mitigate the pounding effects, which can also be abated by using spring-damper restrainers and alleviatory materials.