近场地震作用下大跨高墩连续刚构桥易损性分析

Fragility Analysis of Continuous Rigid Frame Bridge with High Piers and Long Span Subjected to Near‑Field Earthquakes

近场地震作用对于大跨高墩连续刚构桥的破坏性更强。该文以某新建大跨高墩连续刚构桥为依托,考虑近场地震动下桥梁的地震需求概率,运用OpenSees对该连续刚构桥进行时程分析,通过云图法获得桥梁结构在近场地震下的响应,基于结构的曲率需求概率模型对桥梁进行易损性分析。结果表明:大跨高墩连续刚构桥在PGA较低时结构曲率需求概率响应集中,在较大PGA作用下结构的曲率需求概率降低。在近场的罕遇与特罕遇地震作用下,桥墩出现严重损伤和完全破坏的概率几乎为零,桥梁结构在设防场地下能达到中震可修、大震不倒的要求。

Near-field earthquakes are more destructive to the continuous rigid frame bridge with high piers and long span.Based on a new-built continuous rigid frame bridge with high piers and long span,considering the seismic demand probability of bridges under near-field earthquakes,this paper utilized OpenSees to analyze the time history of the bridge.The structure response of the bridge under near-field earthquakes was obtained by the nephogram method,and the vulnerability of the bridge under earthquake was analyzed based on the curvature demand probability model of the structure.The results show that the probability response of curvature demand of a continuous rigid frame bridge with high piers and long span is concentrated when the PGA is low,and the probability response of curvature demand is reduced when the PGA is large.Under the action of nearfield rare and extremely rare earthquakes,the probability of serious damage and complete failure of bridge piers is almost zero,and the bridge structure can be repaired in medium earthquakes and cannot collapse in strong earthquakes.