近断层地震动作用下隔震曲线桥地震反应分析

Seismic Response of Curved Isolated Bridge under Near-fault Ground Motions

研究目的:近年来在多次地震中近断层区域曲线桥遭受到严重破坏,甚至倒塌;与此同时,为提高桥梁的抗震性能,隔震技术逐步应用于桥梁工程中,并表现出良好的隔震效果,因而有必要研究近断层地震动作用下隔震曲线桥梁的地震反应。本文对采用摩擦摆支座的隔震曲线桥进行近断层地震动作用下的地震反应分析,研究近断层地震动对隔震曲线桥地震反应的影响,以期为近断层区域隔震曲线桥梁的设计提供参考。研究结论:(1)近断层脉冲型地震动作用下摩擦摆支座的位移和剪力显著增大,易造成支座破坏,甚至产生落梁;(2)近断层脉冲型地震动作用下桥墩的内力和位移均显著增大,易造成桥墩破坏;(3)在进行隔震曲线桥设计时,应对支座采取限位措施,并提高桥墩的抗震能力;(4)本研究成果可为近断层区域隔震曲线桥的设计提供参考。

Research purposes： In recent years,the curved bridges in the near-fault area have been seriously damaged in many earthquakes,even collapsed. In the meantime,in order to improve the seismic performance of the bridge,the isolation technology is gradually applied in the bridge and exhibits good isolation effect. So it is necessary to study the seismic response of the curved isolated bridge under the near-fault ground motions. In this paper,the analysis on the seismic response of the curved bridge isolated by friction pendulum bearings under the near-fault ground motions is carried out. The influence of the near-fault pulse-like ground motions on the seismic response of the bridge is studied,to provide the design reference of the curved isolated bridge in the near fault zone.Research conclusions：（ 1） The displacement and shearing force of the bearings are obviously increased under the near-fault pulse-like ground motions,so the bearings will be destoried,and the girders will fall down.（ 2） The internal forces and the displacements of piers are significantly increased under the near-fault pulse-like ground motions,which can easily lead to the failure of piers.（ 3） In the design of the isolated bridge,the limit measures should be taken for the bearings and the seismic capacity of the piers should be improved.（ 4） The research results are helpful to the design of the isolated bridge in the near-fault area.