隔震曲线桥地震响应影响因素分析

Analysis of Influential Factors on Seismic Response of Isolated Curved Bridge

研究目的:由于近断层区域曲线桥的震害严重,为提高其抗震性能开始逐步采用隔震技术,因而有必要对近断层地震动作用下隔震曲线桥的地震响应进行影响因素分析,进一步优化近断层区域隔震曲线桥的设计。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,研究曲率半径、桥墩高度和地震动输入方向对隔震曲线桥地震响应的影响。研究结论:(1)圆心角大于30°时,曲率半径对隔震曲线桥的支座和边墩的受力性能影响较大;圆心角小于30°时,隔震曲线桥可按照直线桥进行设计;(2)由于采用隔震技术,桥墩高度对下部结构桥墩的受力性能影响较大,而对隔震支座和上部梁体的影响较小;(3)对隔震曲线桥中的桥墩进行设计时应考虑最不利的地震动输入方向,可沿桥墩平面的法向输入地震动对桥墩进行地震响应分析;(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:Due to the severe seismic damage of the curved bridge in the near-fault area,the isolation technology is gradually adopted to improve their seismic performance.Therefore,it is necessary to analyze the influential factors on the seismic response of the isolated bridge under the near-fault ground motion,so as to optimize the design of the isolated curved bridge in the near-fault area.In this paper,the seismic response of the isolated curved bridge with friction pendulum bearings under the near-fault ground motions is carried out,the influence of curvature radius,pier height and input direction of ground motion on the seismic response of isolated curved bridge is studied.Research conclusions:(1)When the central angle is greater than 30 degree,the curvature radius has a great influence on the bearing and side piers of the isolated curved bridge;when the central angle is less than 30 degree,the isolated curved bridge can be designed according to the straight line bridge.(2)Due to the isolation technology,the pier height has a greater influence on the mechanical performance of the piers,but has less influence on the bearings and the upper beam body.(3)The most unfavorable input direction of the ground motion should be considered in designing the piers of the isolated curved bridge.The seismic response of the pier can be analyzed by inputting the ground motion along the normal direction of the pier plane.(4)The research results are helpful to the design of the isolated curved bridge in the near-fault area.