中文摘要：

针对目前我国桥梁抗震设计规范仅适用于墩高40m以下规则桥梁的现状,以一常见山区高墩大跨连续刚构桥为研究对象,采用IDA方法分析了桥梁结构在15条地震动下的动态响应,得到桥墩各截面在所有地震动作用下的曲率包络图。以高墩最不利截面的材料损伤应变所对应的截面曲率为损伤指标,结合能力需求比对数回归分析,计算了高墩在不同损伤状态下的破坏概率,建立了墩柱易损性曲线,同时还建立了梁端支座的易损性曲线。基于联合失效概率分析方法,形成了桥梁系统易损性曲线。分析结果表明：薄壁空心墩连续刚构桥在强地震作用下高墩发生破坏的部位主要集中在墩顶和墩底区域;墩柱发生完全破坏的概率极小,但桥台处梁端活动支座的地震损伤概率较高;桥梁系统损伤概率能够更加准确地反映高墩大跨桥梁的真实抗震性能。

英文摘要：

Based on the restriction of Chinese seismic design criterion,which is only applied to regular bridges whose column heigths are lower than 40 m,a typical high pier and long span rigid bridge is used in this study.This paper presents the curvature envelopes of columns under many earthquake ground motion records using the incremental dynamic analysis（IDA） method.Curvatures of the most unfavorable section corresponding to the material damage are chosen as a damage status,and the regression analysis of ln（capacity to demand） versus ln（PGA） is performed.Then the probability of expected damage is computed,and the fragility curves of both column and bearing are formed.Based on the joint probability method,the system fragility curve of bridge is formed.It is observed that the damage area of high pier is concentrated on top and bottom of the column with hollow and thin wall under a strong earthquake.The probability of complete damage is hardly happened but the failure probability of rolled bearing is high.The bridge system fragility is more reasonable for the true seismic performance of high pier and long span bridges.