LRB隔震斜拉桥地震响应分析

Analysis on seismic response of lead rubber bearings in cable-stayed bridge

以南昌朝阳桥为研究对象,采用Opensees软件中Steel02材料本构模拟隔震支座本构曲线,建立了LRB隔震多塔斜拉桥和未隔震多塔斜拉桥模型.为使LRB减隔震设计更加可靠,采用了单指标分析进行LRB隔震支座的参数选择,讨论了硬化比对隔震效果的影响.运用Opensees软件,分别采用El-Centro、迁安和Taft等3条地震波进行了三向地震响应分析,对比分析了隔震和未隔震斜拉桥模型的地震响应.分析结果表明:单指标分析选择的铅芯橡胶支座具有良好的隔震效果,能有效地减小斜拉桥的地震响应;支座的硬化比对斜拉桥的隔震效果影响较小.

To make the seismic isolation design more reasonable,the lead rubber bearing( LRB) isolation parameters were selected by single index analysis to discuss the effect of stiffness ratio on seismic isolation. Two analysis models of the bridges with LRB and without LRB were established for Nanchang Chaoyang Bridge,and the Steel02 material was adopted to simulate the hysteric characteristic of LRB.Combining the numerical examples of El-Centro,Qian'an and Taft seismic waves,the comparison of timehistory analyses in the two computation models was carried out by Opensees software. The results indicate that LRB has remarkable efficiency on seismic isolation and can effectively reduce seismic response of cable-stayed bridge. The stiffness ratio has slight effect on cable-stayed bridge seismic isolation.