行波效应下高墩多塔斜拉桥地震易损性分析  

Seismic Fragility Analysis of High-pier Multi-tower Cable-stayed Bridge Under Traveling Wave Effect

作　　者：李立峰[1,2] 曹方亮 胡思聪[1,2] 陈明玉 LI Li-feng;CAO Fang-liang;HU Si cong;CHEN Ming-yu(College of Civil Engineering,Hunan University,Changsha 410082,Hunan,China;Key Laboratory for Wind and Bridge Engineering of Hunan Province,Hunan University,Changsha 410082,Hunan,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南大学风工程与桥梁工程湖南省重点实验室,湖南长沙410082

出　　处：《建筑科学与工程学报》2019年第2期77-83,共7页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51278183);交通运输部建设科技项目(2013 318 798 320);陕西省交通运输厅科技项目(17-19K)

摘　　要：为了研究行波效应对大跨高墩多塔斜拉桥抗震性能的影响,以一座超高墩四塔斜拉桥工程实例为分析对象,采用概率性的易损性分析方法,选用OpenSees抗震有限元分析软件,建立全桥非线性动力有限元模型。从PEER数据库中选取80条有代表性的地震波数据,采用位移输入法进行地震波的多点输入以计入行波效应的影响,考虑7种不同剪切波速和一致激励情况,完成全过程非线性分析。结合大桥特点,考虑3种纵向约束体系,选择支座、斜拉索、主梁和桥塔作为易损构件,并通过比较后选取PGD(地震波峰值位移)作为地震动强度指标,建立结构地震概率需求模型,计算和绘制了易损构件的易损性曲线,选择MPGD值(损伤超越概率P_f=50%对应构件的PGD值)作为构件损伤评价指标。结果表明:支座是最易损伤的构件,桥塔相对来说易损性最小;行波效应对支座的抗震有利,对纵向全约束和半约束体系的抗震也有利;随着波速的增加,各构件和体系的抗震水平基本趋于一致激励的结果。In order to study the influence of traveling wave effect on seismic performance of long-span high-pier multi-tower cable-stayed bridge, a four-tower cable-stayed bridge with ultra high-pier was taken as the analysis object, and the fragility analysis method based on probability was used. The seismic finite element analysis software OpenSees was used to establish the nonlinear dynamic finite element model of whole bridge. A suite of 80 ground motions typically were selected from database PEER, and the displacement input method was used to carry out multi-point excitations to account for the influence of traveling wave effect. Considering seven different shear wave velocities and uniform excitation, the whole process of non-linear analysis was completed. According to the characteristics of bridge, considering three kinds of longitudinal restraint systems of whole bridge, the supports, cables, girders and pylons were selected as vulnerable members, and PGD(peak ground displacement) was selected as the index of earthquake ground motion intensity after comparison. The seismic probabilistic demand model of structures was established, the fragility curves of fragility members were calculated and drawn, and the MPGD(PGD value of component corresponding damage transcendence probability P_f = 50%) was selected as the damage evaluation index of components. The results show that the support is the most vulnerable component, and the tower is relatively minimal in vulnerability. The traveling wave effect is beneficial to the seismic resistance of the support, the longitudinal fully constraint and semi-constraint systems. With the increase of wave speed, the seismic resistance of various components and systems tends to be the result of uniform excitation.

关 键 词：斜拉桥 行波效应 地震易损性 一致激励 

分 类 号：TU311[建筑科学—结构工程]