中小跨径梁桥地震易损性分析

Seismic vulnerability analysis of medium and small span beam bridges

以一座具有较大墩高差异的中小跨径梁桥为例,利用OpenSees有限元软件,考虑地震动的不确定性,建立了该桥的非线性分析模型,合理选取了100条地震动与该模型组合得到所需桥梁样本,计算分析得到该桥的地震响应。选取合理损伤评价指标分别定义桥墩和支座的不同破坏状态,建立了桥墩和支座在纵桥向和横桥向的地震易损性曲线并进行对比分析。结果表明:地震作用下,桥墩和支座均容易发生损伤,支座发生损伤的概率更大,尤其是滑动支座;设置滑动支座的桥墩在地震作用下的损伤概率较低,不易发生严重的损伤;需要对支座和桥墩采取一定的加固和保护措施。

Taking a medium and small span beam bridge with significant differences in pier height as an example,using OpenSees finite element software,considering the uncertainty of seismic motion,a nonlinear analysis model of the bridge was established.100 seismic motions were reasonably selected and combined with the model to obtain the required bridge samples,and the seismic response of the bridge was calculated and analyzed.The reasonable damage evaluation indicators were selected to define different failure states of bridge piers and bearings,the seismic vulnerability curves of bridge piers and bearings in the longitudinal and transverse directions were established,and the comparative analysis was conducted.The results show that under earthquake action,both bridge piers and bearings are prone to damage,and the probability of bearing damage is higher,especially for sliding bearings.Piers with sliding bearings have a low probability of damage under seismic action and are less prone to serious damage.It is necessary to take certain reinforcement and protection measures for the bearings and piers.