基于IDA的大跨连续梁桥地震易损性分析

摘要

目的 分析公路连续梁桥的地震易损性,为该类桥的多级设防抗震设计研究提供理论依据.方法 基于性能抗震设计思想,确定结构的5个性能水准,以桥墩的位移延性比作为性能量化指标,计算桥梁不同极限状态的损伤界限值.在此基础上,采用IDA分析方法计算20条人工拟合地震波作用下的地震响应,基于可靠度理论进行对数回归拟合分析,最终获得地震易损性曲线.结果 理论易损性曲线表明该桥具有良好的综合抗震性能,在0.3g地震动作用下,轻微损伤、中等损伤和严重损伤的概率分别为57.9％、44.7％和3.6％.结论 易损性分析结果可以反映桥梁的综合抗震性能和各级损伤状态的超越概率,对分析整个交通路网的抗震性能和制定紧急救援方案具有指导意义.%The analysis of seismic vulnerability of highway continuous beam bridge provides a theoretical basis for the multi-stage fortification and seismic design of the bridge.Based on performance seismic method,five levels of structure performance were defined.The bridge damage threshold values for different damage limit state were studied by taking displacement ductility ratio of the pier as a quantitative performance metrc.Then,the seismic response under the action of 20 artificial earthquake ground motion curves were calculated by using the incremental dynamic analysis (IDA) method.Finally,the seismic vulnerability curves were obtained.The theoretical vulnerability curve shows that the bridge has a good comprehensive seismic performance.And the probability of slight damage,moderate damage and severe damage is 57.9％,44.7％ and 3.6％,respectively,under the action of 0.3 g ground motion.The results obtained by the vulnerability analysis can be used to reflect the bridge seismic performance and damage probability.And it also has guiding significance for analyzing the seismic performance of the whole traffic network and making emergency rescue plan.