基于改进随机地震动模型的概率反应谱

Probability response spectrum based on improved stochastic model for earthquake ground motion

结合我国现行抗震规范(GB 50011—2010),给出一种改进随机地震动模型的相关参数。推导单自由度体系(SDOFS)弹性加速度需求的条件概率模型,进而建立弹性SDOFS的概率加速度需求谱以及概率位移需求谱。在此基础上,据强度折减系数R与延性系数μ之间的关系,确定SDOFS非弹性位移需求的条件概率分布函数,进而运用随机振动理论和概率方法,建立非弹性SDOFS在给定强度地震作用下及50 a设计基准期内的概率位移需求谱。从美国太平洋地震工程研究中心收集大量实测地震记录,基于大量SDOFS动力时程分析的统计结果,对本文方法所得的理论结果进行Monte Carlo数值验证。研究结果表明:该理论方法准确、合理,且计算效率高。

The parameters of an improved stochastic model for earthquake ground motion were determined according to current seismic code（GB 50011 — 2010）,the conditional probability model of elastic acceleration demand was deduced for SDOF system, and the probability spectrum of displacement demand and acceleration demand were established.Considering the relationship between the strength reduction factor R and the ductility factor μ, the conditional probability distribution function was derived for non-linear displacement demand of SDOF system. Then according to the random vibration theory and probabilistic methods, the probability displacement spectrum was established for inelastic SDOF system under given earthquake intensity or in 50 years design reference period. Using the ground motion records collected from U.S. Pacific Earthquake Engineering Research Center, dynamic time-history analyses of SDOF system were carried out, and the statistical results of time-history analyses were compared with the theoretical solutions to verify their accuracy. The results show that the theoretical method is accurate, reasonable, and the efficiency in computation is high.