渝昆高铁典型连续梁桥地震易损性分析

为评估渝昆高铁典型三跨连续梁桥的抗震性能,基于概率地震需求分析方法对该桥进行理论地震易损性分析。选取渝昆高铁沿线实测地震动记录作为地震输入,考虑桥梁参数的不确定性,采用拉丁超立方抽样方法生成桥梁有限元模型样本库。基于增量动力时程分析方法,通过对桥梁样本库进行非线性时程分析,获得了各构件地震响应峰值,通过峰值响应与地震动峰值加速度的线性回归分析建立构件地震需求模型。进一步对比研究安装普通球型钢支座与双曲面球型减隔震支座桥梁的地震易损性曲线。研究结果表明:减隔震支座可有效降低制动墩易损概率,优化墩高不等的非规则桥梁结构的抗震性能。其研究方法与结论可为非规则连续梁桥抗震设计提供参考。

Seismic vulnerability analysis of typical continuous girder bridges of Chongqing-Kunming high-speed railway

In order to evaluate the seismic performance of a typical three-span continuous girder bridge of Chongqing-Kunming high-speed railway,the theoretical seismic vulnerability of the bridge is analyzed based on the method of probabilistic seismic demand analysis.The measured ground motion records along the Chongqing-Kunming high-speed railway were selected as the seismic input.Considering the uncertainty of the bridge parameters,the Latin hypercubic sampling method was used to generate the bridge finite element model samples.Based on the incremental dynamic analysis method,the seismic response peak of each component of the bridge was obtained by performing nonlinear time history analysis.The seismic demand model was established by linear regression analysis of peak response and peak acceleration of ground motion.Furthermore,the seismic vulnerability curves of the bridge structure with ordinary spherical steel bearing and hyperboloid spherical seismic isolation bearing were compared.The results show that the seismic isolation bearing can effectively reduce the vulnerability probability of the brake pier and optimize the seismic performance of irregular bridge structures with different pier heights.The research methods and conclusions can provide reference for seismic design of irregular continuous girder bridges.