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以一座最大墩高50m曲线钢管混凝土空间组合桁架连续梁桥为工程背景,采用OpenSees建立其弹塑性三维有限元动力分析模型,从PEER地震数据库中选取10条地震动记录对其进行增量动力分析。以典型墩最不利截面材料损伤应变所对应截面曲率为损伤指标,利用能力需求比对数函数进行回归分析,计算不同构件在不同损伤状态下的破坏概率,建立墩柱易损性曲线和支座易损性曲线。基于联合失效概率分析方法,形成了桥梁系统易损性曲线。同时建立多个对比模型,分析墩跨比和曲线半径对桥梁易损性影响。结果表明:钢管格构桥墩高度差异不大时,和钢筋混凝土桥墩相邻的首个钢管格构桥墩震动响应较大;本桥墩和梁之间大量使用橡胶支座从而形成弹性连接和铰接的减震措施,可有效降低桥梁完全破坏概率;墩跨比增大将导致桥梁系统完全破坏损伤概率随之增大;随着曲线半径增大,损伤概率逐渐增大,曲线桥本身拱结构对顺桥向地震有一定抵抗作用。
Taking a 50 m-span CFST composite truss continuous girder bridge with maximum pier height as engineering background, three-dimensional elasto-plastic finite element dynamic analysis model was established by using OpenSees. Ten dynamic ground motion records were selected from the PEER seismic database for incremental dynamic analysis . Taking the curvature of the section corresponding to the damage strain of the most adverse cross-section material of typical piers as the damage index, the probability of failure under different damage conditions was calculated by using regression analysis of the logarithmic function of capacity requirements, and the vulnerability curve of the pier and the support Vulnerability curve. Based on the joint failure probability analysis method, the bridge system vulnerability curve is formed. At the same time, a number of comparative models were established to analyze the influence of pier span ratio and curve radius on bridge vulnerability. The results show that the vibration responses of the first steel pipe lattice piers adjacent to the reinforced concrete piers are large when there is not much difference in the piers height of the steel pipe lattice piers. Rubber bearings are widely used between the piers and the girders to form the elastic connection and hinged reduction Earthquake measures can effectively reduce the probability of complete destruction of the bridge; pier-span ratio will lead to the complete destruction of the bridge system damage probability increases; as the curve radius increases, the probability of injury gradually increases, the curve arch itself arch structure along the bridge Earthquake has a certain resistance.