Seismic fragility assessment of aqueduct bent structures subjected to mainshock-aftershock sequences
Seismic fragility assessment of aqueduct bent structures subjected to mainshock-aftershock sequences
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DOI：
10.1016/j.engstruct.2023.116505
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发表时间：
2023-10
影响因子：
5.5
通讯作者：
Min-Min Du-Min;Sherong Zhang;Chao Wang;Lei She;Jiabei Li;Tong Lu
中科院分区：
文献类型：
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作者：
Min-Min Du-Min;Sherong Zhang;Chao Wang;Lei She;Jiabei Li;Tong Lu
摘要采用双增量动力分析方法，研究了渡槽排架结构在主-余震地震作用下的地震易损性。在OpenSees平台上建立了渡槽排架结构的有限元模型，并通过物理试验结果验证了数值模拟技术的有效性。对渡槽排架结构进行了一系列非线性动力时程分析，得到了渡槽排架结构在不同地震动烈度下的地震反应。在此基础上，建立了渡槽排架结构增量动力分析（IDA）数据聚类和损伤度量中线。提出了MS-AS地震动序列作用下渡槽排架结构的改进概率地震需求模型。基于所提出的PSDM和预先定义的损伤状态，渡槽排架结构的脆弱性表面也开发采用矢量值的强度措施，考虑主震强度（IMm）和余震强度（IMa）。同时，为了便于比较，绘制了渡槽排架结构在不同主震烈度下的余震易损性曲线，强调了余震在地震危险性评估中的重要性。分析结果表明，所提出的分段概率地震需求模型能够更好地拟合余震强度与钢筋纵向拉应变中位数之间的对数关系。结构易损性概率随主震和余震烈度的增大而增大。结果表明，在MS-AS地震序列作用下，主烈度对渡槽结构的破坏概率起主导作用，余震可对渡槽排架结构造成附加破坏，降低其抗震能力。研究结果可为西南地区渡槽结构的抗震优化设计、恢复力的提高和震后修复提供依据。
This study aims to assess the seismic fragility of the aqueduct bent structure subjected to mainshock-aftershock (MS-AS) ground motion sequences by double incremental dynamic analysis method. The finite element model of the aqueduct bent structure is developed in OpenSees platform and numerical simulation technique is validated through physical test results. A series of nonlinear dynamic time-history analysis is carried out on the aqueduct bent structure to obtain its seismic response under different ground motion intensities. Furthermore, the incremental dynamic analysis (IDA) data cluster and median lines of the damage measure of the aqueduct bent structure are constructed. The advanced probabilistic seismic demand model (PSDM) of the aqueduct bent structure subjected to MS-AS ground motion sequences is proposed. Based on the proposed PSDM and the predefined damage states, the fragility surfaces of the aqueduct bent structure are also developed by adopting the vector-valued intensity measures considering the mainshock intensities (IMm) and aftershock intensities (IMa). Meanwhile, for the sake of comparation, the aftershock fragility curves of the aqueduct bent structure under different mainshock intensities are drawn, which emphasizes the importance of aftershocks in the seismic risk assessment. The analysis results indicate that the proposed piecewise probabilistic seismic demand model can better fit the logarithmic relationship between the aftershock intensities and the median of the reinforcement longitudinal tensile strain. The structural fragility probability increase with the increase of mainshock and aftershock intensities. It turns out that the mainshock intensities play a leading role in the damage probability of the aqueduct structure subjected to MS-AS ground motion sequences, the aftershock can cause additional damage to the aqueduct bent structure and reduce its seismic capacity. The meaningful results can provide supports for seismic optimization design, resilience improvement and post-earthquake repair-demand of the aqueduct structure in Southwest China.