基于能力谱法的单自由度结构易损性分析

Structural Vulnerability Analysis on Single Degree of Freedom System Based on Capacity Spectrum Method

为进行基于能力谱法的结构地震易损性分析,采用选定的250条地震波对单自由度结构进行了弹塑性时程分析和弹性时程分析,建立了结构弹塑性时程分析最大位移与Pushover分析最大位移比的平均值和变异系数与相关参数的关系式,其中Pushover分析中的需求谱采用的是按相同地震波进行弹性时程分析建立的反应谱;通过Monte-Carlo方法分析了随机结构参数下Pushover分析得到的最大位移的概率特性,给出了最大位移平均值和变异系数的表达式;采用可靠度计算理论,给出了结构易损概率的计算公式和可靠指标的简化计算公式。结果表明:提出的易损性分析方法通过Pushover分析实现了传统结构易损性分析方法需要进行大量弹塑性时程计算才能达到的目标。

In order to analyse the structural seismic vulnerability based on capacity spectrum method ,elastic‐plastic and elastic time history analysis under 250 selected seismic wave records were made for structure of single degree of freedom （SDOF） systems .Pushover analysis ,whose respond spectrum was generated by the elastic‐plastic time‐history analysis under the same seismic wave records ,was carried out .The relationship among the mean and variation coefficient of ratio of maximum displacement from elastic analysis to Pushover analysis with the relevant parameters were set .The probabilistic characteristic of the maximum displacement obtained from Pushover analysis of stochastic structures were generated by Monte‐Carlo method according to the probability distribution of structural parameters . Based on the reliability theory , the expressions for calculating the vulnerability probability and reliability index were presented .The proposed method for vulnerability analysis can conceivably substitute the time‐consuming process of traditional time‐history method by Pushover analysis .