文章摘要

文章信息/Info

Title:: Probabilistic Seismic Demand Model Considering the Effect of Duration of Strong Ground Motion

Author(s):: CHEN Liang; LI Jian-zhong; SHENG Guang-zu; (Department of Bridge Engineering of Tongji University,Shanghai 200092,China)

Keywords:: strong ground motion; duration; performance-based earthquake engineering; column of RC bridge; probabilistic seismic demand model

摘要:: 选择合理的持时衰减关系,利用Monte-Carlo方法,抽取持时样本,根据震级M、震中距R和局部场地土壤条件S以及持时样本,选择符合条件的实际地震波记录,并进行合理的调值,对一座钢筋混凝土桥墩进行了非线性动力时程分析。对比强地面运动持时与能量需求参数和累积破坏参数的相关性,发现:幅值、频谱和持时对能量需求参数和累积破坏参数的影响是强烈耦合的,且强地面运动持时对两者的影响比较显著; 在选择结构第一模态周期谱加速度和合理的能量需求参数,并分别作为地面运动强度参数IM和EDP建立概率地震需求模型时,要考虑持时的影响。

Abstract:: Probabilistic seismic demand model(PSDM)is an important part of the performance-based earthquake engineering methodology which necessitates the probabilistic evaluation of engineering demand parameters(EDP).There is the most significant influence of the variability of strong motions on the probabilistic evaluation of EDP,such as the influence of the duration of strong motion.We select reasonable attenuation relationship of duration of strong motion,the samples of duration using Monte-Carlo method,the condition-matched earthquake records according to magnitude,epicentral distance,local soil conditions and the samples of duration,and analyze the nonlinear dynamic time history on a RC column using selected records by reasonable scaling.Through comparing the correlation between the duration of ground motion and the energy demand measures and cumulated damage measures,we find that the influences of amplitude,spectral characteristics and duration on two measures above are strongly coupled and the influence of duration on them is significant.Moreover,when the first mode period spectral acceleration and reasonable energetic demand measures are used to be intensity measure and EDP respectively to build PSDM,the influence of duration should be considered.