全非平稳地震作用的结构随机反应与可靠度分析

Stochastic Responses and Reliability Analysis of Structures Subjected to Fully Nonstationary Ground Motion

在平稳地震动过程的Clough-Penzien功率谱基础上,采用林家浩非均匀调制函数建立全非平稳地震动过程的演变功率谱。根据我国现行的《建筑抗震设计规范》进行全非平稳地震动演变功率谱的参数识别研究。应用非平稳随机过程模拟的谱表示-随机函数方法,生成建筑结构抗震设计所用地震动的代表性样本集合。通过代表性样本集合的二阶统计值及地震反应谱与目标值的拟合比较,验证本文方法的有效性。最后结合概率密度演化方法,进行以层间位移角为控制准则的结构随机地震反应分析与抗震可靠度计算。

This paper proposes a new probability model for the fully nonstationary ground motion acceleration process,and provides a kind of seismic input for structures for use in seismic research.First,based on the Clough-Penzien power spectrum of the stationary ground motion process,we establish the evolutionary power spectrum of the fully nonstationary ground motion process.Most importantly,the evolutionary power spectrum considers not only the nonstationary intensity,but also the nonstationary frequency.Then,based on the seismic design building code（in China）,we identify these parameters in the evolutionary power spectrum model for different site conditions.Meanwhile,we applied the spectral representation-random functions method to generate an ensemble of 152 representative samples,and assigned each representative sample a given probability.This method uses a few basic random variables to express the original seismic ground motion process.Next,we obtain second-order statistics and the seismic response spectrum of the representative sample ensemble,and compare them with the target values.The results show that the general characteristics of all 152 representative samples coincide well with the target values.In this study,to verify the superiority and effectiveness of the proposed method,we used ANASYS software to conduct a dynamic time-history analysis of a concrete framework.Finally,by combining the recent probability density evolution method with the control criteria for the displacement angle,we performed a stochastic dynamic response analysis and reliability calculation for the concrete framework.