主余震序列作用下结构增量损伤比研究

STUDY ON INCREMENTAL DAMAGE RATIOS OF STRUCTURES DUE TO MAINSHOCK-AFTERSHOCK EARTHQUAKE SEQUENCES

该文以非线性单自由度体系为研究对象,挑选了662条真实主余震序列作为地震动输入,采用Park和Ang提出的损伤指数作为结构损伤指标,对主余震序列作用下的结构主震损伤、余震增量损伤和主余震累积损伤在结构全周期范围内进行了分析。提出了增量损伤比参数(余震增量损伤/主震损伤),开展了增量损伤比与主余震强度比(余震强度/主震强度)的相关性分析,建立了以结构周期与主余震强度比为参数的增量损伤比预测模型,并对模型的预测精度及其受滞回模型的影响进行了讨论。结果表明:增量损伤比与主余震强度比之间存在较高的对数线性相关性,该文提出的增量损伤比预测模型精度较高,滞回模型对增量损伤比预测模型的精度影响较大。

It takes single-degree-of-freedom systems as objectives.A set of 662 mainshock-aftershock sequences is selected as the earthquake inputs.The damage index proposed by Park and Ang is adopted as the damage indicator.Then the mainshock-damages,aftershock-induced damage increments and accumulated damage under the action of mainshock-aftershock sequences are examined at entire structural periods.An incremental damage ratio(i.e.,a ratio between aftershock-induced damage increment and mainshock damage)is proposed.The correlation between the incremental damage ratio and the mainshock-aftershock intensity ratio(i.e.,a ratio between aftershock intensity measure and mainshock intensity measure)is investigated.A prediction model for the incremental damage ratio is developed as a function of the mainshock-aftershock intensity ratio and of the structural period.The accuracy of the prediction model and the influence of different SDOF systems are discussed.The results show that the incremental damage ratios have a good linear interdependence with the mainshock-aftershock intensity ratio in the logarithm space.The prediction model for the incremental damage ratio shows sufficient accuracy.Moreover,the hysteretic models of SDOF systems have a significant effect on the accuracy of the incremental damage ratio prediction model.