非规则大跨刚构-连续组合桥地震易损性分析

Seismic Vulnerability Fragility Analysis of Irregular High-pier and Long-span Rigid Frame Continuous Composite Bridge

以某西部山区薄壁大跨刚构-连续组合桥梁为研究对象,分析了非规则大跨刚构-连续组合桥梁纵、横向地震易损性。基于OpenSees平台,建立了其非线性纤维有限元模型。采用曲率作为墩柱损伤指标,位移作为活动盆式支座损伤指标,基于IDA方法分析了该桥在不同地震动下的动态响应,得到桥墩纵、横向地震动作用下的曲率包络图,分析了不同桥墩构造的破坏情况,建立了墩柱以及支座的易损性曲线,讨论了不同墩高对桥墩地震易损性的影响。结果表明:桥墩的纵向地震损伤概率大于横向损伤概率,且墩高越高损伤概率越小;支座横向地震损伤概率大于纵向损伤概率。其研究结果可为非规则刚构-连续组合桥梁的抗震设计提供参考和依据。

In order to study the seismic vulnerability of irregular long-span rigid frame continuous composite bridge under longitudinal and transverse earthquake ground motions, one certain western mountain long-span rigid frame continuous composite bridge with hollow thin-walled pier is taken as the research object. The analytical fiber model is established in light of the bridge con- figuration aided by OpenSees software. The incremental dynamic analysis （IDA） method is a- dopted to obtain the bridge structural seismic responses under 240 earthquake ground motion re- cords, then the curvature envelopes for each pier under longitudinal and transverse earthquake ground motions are got. Moreover, the curvature and displacement are respectively regarded as the damage index of the piers and bearings to figure out the failure probabilities of different dam- age states, and the vulnerability curves are formed finally. The results show that the seismic vul- nerability of piers are mainly influenced by the longitudinal earthquake ground motions and with the increase of the pier height, the damage probability decreases. The seismic vulnerability of the bearings is controlled by the transverse earthquake ground motions. The research results can pro- vide references for seismic design of long-span rigid frame continuous composite bridges.