考虑地震动持时效应的加载制度对结构的影响

Study on loading protocol of structural quasi-static test considering strong motion duration effect

历次大地震震害表明,地震动持时对工程结构累积损伤有显著影响,长持时地震动作用下结构损伤明显加重,因此,确定地震动持时对结构地震反应及损伤的定量影响成为热门研究课题。拟静力试验是模拟结构地震反应的重要手段,但目前其加载制度未考虑地震动持时影响。选取考虑俯冲区长持时地震动作用的加载制度和规范建议的加载制度,利用OpenSees有限元软件建立RC柱结构模型,对比分析了FB、DB、HB梁柱单元,选择与试验符合较好的HB梁柱单元进行模拟,结果分析表明:长持时加载制度会不同程度增大结构的耗能退化和刚度退化,规范建议的加载制度不能体现长持时地震动作用下结构的反应。

The earthquake damage investigation shows that the strong motion duration has significant effects on the cumulative damage of engineering structures,and the structural damage is more serious under the excitation of long duration ground motion.To determine the quantitative effect of strong motion duration on structural response and damage has been a hot research topic recently.The quasi-static test is one of the important means to simulate the seismic response of structures,but the loading protocol seldom considers the effects of strong motion duration in most cases.In this paper,the loading system considering the long duration seismic action in the subduction area and the loading system recommended by the code are selected,the RC column structure model is established by using OpenSees finite element software,the FB,DB and HB beam column elements are compared and analyzed,and the HB beam column element which is in good agreement with the test is selected for simulation.Through data analysis,it is found that the long duration loading system will increase the energy consumption degradation and stiffness degradation of the structure to varying degrees,The loading system proposed in the current code can not reflect the response of the structure under long duration ground motion.