基于强度和延性的残余位移比谱及其影响因素分析

Strength-based and ductility-based residual displacement ratio spectrum and its influential factor

结构震后残余位移是抗震性能评估和地震损失评估的重要参数。文中针对理想弹塑性单自由度体系,采用与残余位移相关性最好的归一化参数定义残余位移比,通过动力时程分析建立统计平均的等延性残余位移比谱和等强度残余位移比谱,研究场地条件、延性系数及强度折减系数对等延性残余位移比谱和等强度残余位移比谱的影响,通过回归分析构建了等延性残余位移比谱和等强度残余位移比谱的预测方程。结果表明:残余位移与弹塑性谱位移的相关性较大,与弹性谱位移的相关性较小;软土场地下结构残余位移的评估需考虑场地条件的影响;残余位移比离散性受延性系数和强度折减系数影响显著。

The residual displacement is an important parameter for the evaluation of seismic performance and loss in building resulting from earthquakes.The best normalization parameter was selected by correlation analysis,and the residual displacement ratios for elastic-perfectly-plastic single-degree-of freedom oscillators were defined by using this normalization parameter.The constant-strength residual displacement ratio spectrum(CSRDRS)and constant-ductility residual displacement ratio spectrum(CDRDRS)were constructed by means of nonlinear response time-history analyses.The results were statistically organized to evaluate the influence of the following parameters:site condition,ductility ratio and lateral strength ratio.A simplified expression was presented to estimate CSRDRS and CDRDRS for elastic-perfectly-plastic systems.It is concluded that the correlation between the residual displacements and the inelastic spectral displacements is larger,but the correlation coefficient between the residual displacements and the elastic spectral displacements is smaller.The influence of site conditions must be considered in the evaluation of structural residual displacement,especially in soft soil site.The dispersion of CDRDRS and CSRDRS is significantly affected by ductility ratio and lateral strength ratio,respectively.