强震作用下斜拉桥纵桥向非线性地震反应分析  

Analysis of Nonlinear Seismic Response of Cable-Stayed Bridge Subjected to Longitudinal Strong Ground Motions

作　　者：徐艳[1] 段昕智[1] 李建中[1] 

机构地区：[1]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《华南理工大学学报（自然科学版）》2012年第6期132-138,共7页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51008225);交通部西部交通建设科技项目(200631882225)

摘　　要：为研究斜拉桥在纵桥向强震作用下的抗震性能,对某具有一定代表性的中等跨度斜拉桥,通过线性能力需求比的确定,合理引入能考虑塑性发展的非线性弹塑性单元,研究纵桥向强震作用下桥梁各主要构件的塑性发展状况及其对全桥地震反应的影响.结果表明:在强地震动作用下,桥塔、墩等构件的塑性发展不但与地震波的特性还与地震波的强度相关;斜拉桥的桥塔存在先于辅助墩和边墩屈服的可能性;桥塔屈服将显著减小塔柱下部结构的地震需求.由此得到以下结论:在强震作用下,需考虑桥塔的非线性地震响应及其对桥梁整体抗震性能的影响;以目前的工程设计来看,在纵桥向强震作用下,桥塔、墩各截面仍有一定的塑性能力储备.This paper deals with the seismic performance of cable-stayed bridges subjected to longitudinal strong ground motions,with one typical medium-span cable-stayed bridge as the research object.In the investigation,the linear seismic capacity-to-demand ratio of the bridge is determined,based on which different types of nonlinear electroplastic elements are introduced to reveal the plastic behaviors of the main bridge components as well as their effects on the whole-bridge seismic response.The results show that（1） under strong ground motions,the plastic behaviors of the bridge tower and the piers correlate with not only the characteristics but also the intensity of seismic waves;（2） the bridge tower may yield before the auxiliary and the side piers do;and（3） the yielding of the bridge tower results in a significant reduction of seismic-induced moment of tower columns.Therefore,in strong earthquakes,it is necessary to take into consideration the nonlinear seismic response of the bridge tower and its effect on the seismic performance of the whole bridge.Meanwhile,in current practical design,the bridge tower and piers may still conserve certain plasticity margin under longitudinal strong ground motions.

关 键 词：斜拉桥 强地震动 抗震性能 地震反应 线性能力需求比 非线性弹塑性单元 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]