Fragility analysis of high-span aqueduct structure under near-fault and far-field ground motions
Fragility analysis of high-span aqueduct structure under near-fault and far-field ground motions
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DOI：
10.1016/j.istruc.2022.10.096
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发表时间：
2022-12
期刊：
影响因子：
4.1
通讯作者：
Sherong Zhang;Min-Min Du-Min;Chao Wang;Benbo Sun;Lei She;Wenjie Liu
中科院分区：
文献类型：
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作者：
Sherong Zhang;Min-Min Du-Min;Chao Wang;Benbo Sun;Lei She;Wenjie Liu
已有研究表明，近断层脉冲型地震动具有速度脉冲大、速度敏感区窄、周期效应长等显著特点，其引起的建筑结构地震反应与远场地震动有显著差异。目前，关于非线性地震动对渡槽结构损伤演化特性的影响尚缺乏研究。此外，现行的抗震设计规范并没有对渡槽结构在NFP地震动作用下的动力反应提供设计建议。本文的重点是定量评估高跨渡槽系统在NFP和FF地震动作用下的脆弱性。为此，10个记录的NFP和FF地震动被认为是，渡槽支座位移和桥墩偏移比被选为性能评价指标。在此基础上，引入Copula函数，建立了考虑渡槽支座和墩柱构件地震需求相关性的大跨渡槽体系的易损性曲线。结果表明，在相同地震动烈度条件下，渡槽支座在不同性能水平下的易损概率明显大于槽墩，在抗震设计中应予以考虑。此外，渡槽结构的易损性概率曲线采用单一构件的易损性概率来描述，高估了渡槽结构的抗震性能。高跨渡槽结构在NFP地震动作用下的易损性显著大于FF地震动作用下的易损性。因此，渡槽的抗震安全评估和抗震设计应考虑NFP地震动的影响。
Previous studies have shown that due to the notable characteristics of near-fault pulse-type (NFP) ground motions, such as large velocity pulse, narrow velocity-sensitive region and long period effect, there are significant differences in the seismic response of building structures caused by NFP ground motions and far-field (FF) ground motions. At present, the effect of NFP ground motions on the damage evolution characteristics of the aqueduct is still lacking. In addition, the current seismic design codes do not provide design recommendations for the dynamic response of aqueduct structures under NFP ground motions. The focus of this manuscript is to quantitatively evaluate the fragility of a high-span aqueduct system under NFP and FF ground motions. For this purpose, 10 as-recorded NFP and FF ground motions are considered, and the aqueduct bearing displacements and pier offset ratios are selected as performance evaluation indices. Then, the copula functions are introduced to establish the fragility curve of the high-span aqueduct system considering the seismic demand correlation of the aqueduct bearing and pier components. The results indicate that under same ground motion intensity conditions, the fragility probability of the aqueduct bearings is significantly larger than that of the trough pier under different performance levels, and should be considered in seismic design. In addition, the fragility probability curve of a single aqueduct component is used to describe the fragility probability of the aqueduct system, which overestimates its seismic performance. The fragility probability of a high-span aqueduct system under NFP ground motions is significantly greater than that under FF ground motions. Therefore, seismic safety assessments and seismic designs for the aqueducts should take into account the influence of NFP ground motions.