基于多个响应量的拱坝地震易损性分析

以白鹤滩拱坝为研究对象,选取成组强震记录,同时考虑地震动和材料的不确定性,采用增量法对白鹤滩拱坝进行了地震易损性分析。统计连续调幅地震动作用下拱坝损伤破坏过程,直观的划分了拱坝地震破坏等级,确定了拱冠位移、横缝开度和损伤体积比这三个响应量在各破坏等级间的界限值,从而可通过这三个响应量定量描述拱坝的破坏等级。通过拟合增量动力分析结果,分别建立了三个响应量的概率地震需求模型,进而求得地震易损性曲线,并综合比较了不同破坏等级下基于三个响应量的易损性曲线,全面反映了拱坝易损性。利用易损性曲线可以预测不同强度地震作用下拱坝达到各级破坏的概率,为基于性能的拱坝抗震安全评价提供了理论依据。

Seismic fragility analysis for arch dam based on multiple responses

A structural fragility model provides an effective tool for safety evaluation by utilizing a probabilistic framework to consider uncertainty factors affecting structural performance. Here, Baihetan arch dam was taken as the study object, selecting a group of strong earthquake records, considering uncertainties of earthquakes and materials, the incremental method was used to do seismic fragility analysis for Baihetan arch dam.The damage and failure process of the arch dam under ground motion with continuous amplitude-modulation was counted to intuitively divide seismic damage grades of the arch dam, and determine boundary values among various damage grades of 3 responses including arch crown displacement, transverse seam opening and damage volume ratio. Through fitting the results of IDA, probabilistic seismic demand models of 3 responses were established, respectively, and then seismic fragility curves were solved. Fragility curves based on 3 responses under different damage grades were comprehensively compared to fully reflect the fragility of the arch dam. It was shown that seismic fragility curves can be used to predict probabilities of the arch dam reaching various damage grades under action of earthquakes with different intensities; the study results provide a theoretical basis for seismic safety evaluation of arch dams based on performance.