考虑桩径效应的桥梁结构地震风险分析

Seismic risk analysis of bridge structure considering pile diameter effect

桩-土-结构相互作用是桥梁结构地震反应分析的重要问题,其中桩径效应不应忽略。以一座三跨连续梁桥为例,研究桩径效应对桥梁地震风险的影响。具体建立三种有限元模型:模型一是同时考虑桩-土-结构相互作用和桩径效应;模型二是考虑桩-土-结构相互作用,但没有考虑桩径效应;模型三是墩底固结的简化模型。通过增量动力分析方法计算桥梁结构的地震易损性曲线和地震风险曲线,对三种模型的计算结果进行对比分析。结果表明,同时考虑桩-土-结构相互作用和桩径效应的模型对应地震易损性与地震风险最高;墩底固结的模型对应地震易损性和地震风险最低。

Pile-soil-structure interaction is an important problem in seismic response analysis of bridge structures,where pile diameter effect should not be ignored.Here,taking a three-span continuous beam bridge as an example,effects of pile diameter effect on bridge seismic risk was studied.Three kinds of finite element models of model1 simultaneously considering pile-soil-structure interaction and pile diameter effect,model2 considering pile-soil-structure interaction but not pile diameter effect and model 3 being a simplified model of pier bottom fixed were established.The seismic vulnerability curve and seismic risk curve of the bridge structure were calculated with the incremental dynamic analysis method.The contrastive analysis was performed for the calculation results of the three models.The results showed that model1 simultaneously considering pile-soil-structure interaction and pile diameter effect has the highest seismic vulnerability and seismic risk;model 3 with pier bottom fixed has the lowest seismic vulnerability and seismic risk.