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采用扩展增量动力分析方法,建立了汶川地区典型简支梁桥的分析型地震易损性模型。依据汶川地震桥梁震后调查资料,评估了桥梁结构参数的不确定性,通过抽样并建立一系列桥梁的有限元模型样本。将汶川地震实测地震波调幅至不同的地震动强度,对每一级地震动强度下对不同样本进行非线性动力时程分析,记录桥梁各构件对应的地震峰值响应并绘制成IDA曲线。基于EDP准则和IM准则2种不同方法,分别计算得到不同地震动强度下桥梁发生各损伤状态的离散概率数据点,采用最小二乘法回归得到不同损伤状态对应的桥梁构件和系统地震易损性曲线。生成的地震易损性曲线可以进一步用于交通网络系统的地震风险评估和震后加固优先级决策。
Analytical seismic vulnerability model of a typical simply supported beam bridge in Wenchuan has been established by means of extended incremental dynamic analysis. Based on the post-earthquake survey data of the Wenchuan earthquake bridge, the uncertainty of the structural parameters of the bridge was evaluated. A series of finite element model samples of the bridge were established by sampling. The measured seismic waves of Wenchuan earthquake were amplitude modulated to different ground motions, and nonlinear dynamic time history analysis of different samples under each ground motional intensity was carried out. Corresponding seismic peak responses of all members of bridge were recorded and plotted as IDA curves. Based on two different methods of EDP criterion and IM criterion, the discrete probability data points of each damage state of bridges under different ground motions are calculated respectively. The seismic vulnerability curves of bridge members and systems corresponding to different damage states are obtained by least squares regression . The generated seismic vulnerability curve can be further used for seismic risk assessment and post-earthquake reinforcement priority decision-making in traffic network systems.