两水准地震设防下的斜拉桥体系易损性分析  

System Fragility Analysis for Cable-stayed Bridges Under Two Level Seismic Hazard

作　　者：钟剑[1] 任伟新[1] 万华平 袁万城[2] 

机构地区：[1]合肥工业大学土木与水利工程学院,安徽合肥230009 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《中国公路学报》2017年第12期101-109,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金青年基金项目(51608161;51508144);博士后科学基金面上项目(2016M602007)

摘　　要：针对中国规范所定义的E1,E2地震下的结构性能进行的地震易损性研究尚不充分问题,提出两水准地震作用下结构性能的概率评估方法,推导了设计地震下地震风险的理论公式,并以特大跨斜拉桥为例来阐述该方法,建立考虑多种非线性效应的斜拉桥有限元模型,斜拉桥关键构件(桥塔、桥台、支座、阻尼器)和结构体系的概率需求地震模型以及地震易损性方程;拟合所在场地的地震危险性曲线方程,得到不同重现期地震下构件和体系的损伤概率;计算E1,E2两水准地震下的构件损伤概率,以多个构件的性能水平为目标,基于蒙特卡洛模拟抽样方法得到桥梁的体系易损性曲线,计算体系地震风险;基于提出的两水准地震设防下的斜拉桥体系易损性分析方法,进一步比较了使用阻尼器加固前后斜拉桥在E1和E2两水准地震下的体系易损性。结果表明:安装阻尼器以后斜拉桥在设计地震作用下的各个关键构件以及结构体系的损伤概率大大降低;表明两水准地震设防下的斜拉桥体系易损性分析方法可以为斜拉桥概率性抗震设计及加固提供实践方法。In allusion to the problem of few researches on seismic fragility on the basis of structural performance under E1 and E2 earthquake in the Chinese code, the probabilistic methodology to evaluate the seismic performance of bridge under the two horizontal earthquake actions was proposed, and theoretical formula of seismic hazard under the design earthquake was deduced. This approach was exemplified in detail by a long-span cable-stayed bridge. The finite element model of a cable-stayed bridge was established considering a variety of nonlinear effects. The probabilistic seismic demand model （PSDM） and fragility functions of critical components （pylon, abutment, bearing, and fluid viscous damper） and bridge system of the cable-stayed bridge were established. Through the fitting of seismic hazard curvilinear equation, the damage probability of components and systems during different earthquake return period was obtained.The damage probability of the bridge under E1 and E2 earthquake was calculated using the closed form expression. The Monte Carlo simulation method was used to obtain the system fragility curves and seismic hazard based on the performance level of main components. The system fragility of cable-stayed bridge retrofitted with fluid viscous damper （FVD） and as-built bridge was compared under E1 and E2 earthquake based on the system fragility analysis methods for cable-stayed bridges under two-level seismic hazard. The result shows that the FVD can effectively reduce seismic risk of main components and structural systems of cable-stayed bridges under the design earthquake. This methodology will provide the theoretical approach for the performance-based probabilistic seismic design and retrofit of the cable-stayed bridges.

关 键 词：桥梁工程 斜拉桥 易损性曲线 地震风险分析 基于性能的抗震设计 性能目标 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]