中文摘要：

在估计已知强度或延性的现有结构在不同地震动强度下的最大地震弹塑性反应时,弹塑性位移比谱和等延性强度谱是十分准确有效的.通过对342条地震记录进行单自由度体系的弹塑性时程分析,研究了三个特征周期设计分组在不同延性系数下的弹塑性位移比谱特性以及等延性强度谱的特性,通过非线性回归分析建立了等延性位移比谱和等延性强度谱,给出了回归计算公式.研究表明：（1）弹塑性位移比谱在周期为0~1.0 s时谱值随周期的增加急剧下降,下降区间的终点与地震分组有关,之后谱曲线转入平缓,且延性系数对平缓段的曲线影响较小;（2）延性系数μ〉1时,等延性强度谱在周期区间为0-1.0 s时谱值随周期的增加急剧增长,上升区间的终点与地震分组有关,之后谱曲线增长较为平缓,等延性强度谱随延性系数增加而增加;（3）等延性位移比谱和等延性强度谱的回归计算公式能反映延性位移比和折减系数的统计规律,可应用于实际工程.

英文摘要：

In the evaluation of existing structures with known lateral strength or ductility, the elastoplastic displacement ratios spectrum and equivalent constant strength spectrum are particularly accurate and useful to estimate maximum lateral elastoplastic displacement demands on existing structures. Based on the investigations of nonlinear time-history for single degree of freedom （SDOF） system of 324 earthquake ground motion records, the characteristics of the elastoplastic displacement ratios spectrum with various ductility coefficient and the characteristics of the constant-ductility strength spectrum in different design characteristic periods were detailedly studied. By means of nonlinear regression analysis, the simplified calculation formula of inelastic displacement ratios spectrum is fitted out under different ductility coefficient. Result shows that. （1） the plasticity displacement ratio spectrum decreases dramatically with the period when interval is in 0-1.0 seconds, the terminal of the decline period related to the design characteristic periods, after which the spectrum become gently and the effect of the ductility coefficient become less. （2） when ,μ〉1, the constant-ductility strength spectrum increases with the period when interval is in 0-1.0 seconds, the top of the increase period related to the design characteristic periods, after which the spectrum become gently and the constant-ductility strength spectrum increases with ductility coefficient. （3） Regression formula of the constant-displacement ratios spectrum and the constant-ductility strength spectrum are able to reflect the statistical law of the ductility displacement ratio and reduction coefficient. They are capable to be applied in practical engineering.