约束条件对山区高墩桥梁地震易损性的影响

Inf luence of Constraint Conditions on Seismic Vulnerability of High Pier Bridge in Mountain Area

以一座高墩大跨连续刚构桥为原型,利用OpenSEES平台建立桥梁结构的弹塑性动力分析模型,并基于"谱兼容"的方法从PEER数据库中选择20条地震记录,对比分析在不同约束条件下一致激励和多点激励对桥梁结构易损性的影响。结果表明:墩-梁固结可以对桥墩的过度变形产生限制作用,从而使得强震作用下桥墩具有更好的抗震性能;当约束条件为支座连接时,桥墩在强震作用下更容易发生严重损伤,应使用限位装置;当约束条件为墩-梁固结时,行波效应会对桥墩的易损性产生不利影响,使其发生各级别损伤的概率都增大。

The elastic-plastic dynamic analysis model was established by using OpenSEES based on the prototype of a real high pier long span continuous rigid frame bridge.Twenty seismic records were selected from the PEER database using a spectrum compatible method.The inf luences of uniform and multi-point excitations on vulnerability of bridge under different constraint conditions were compared and analyzed.The results show that the pier/beam rigid connection can restrict the excessive deformation of the pier,so that the pier has better anti-seismic performance under strong seismic.When the constraint condition is bearing connection,the pier is more likely to be seriously damaged under strong seismic.The corresponding limit devices should be used to avoid serious damage to the piers.When the constraint condition is pier/beam rigid connection,the wave-passage effect will have adverse effect on the vulnerability of the piers and increase the probability of pier damage at all levels.