基于SDOF体系考虑地震动持时的强度指标分析

文中从PEER地震动数据库选取60条具有不同持时的地震动记录,并将峰值加速度(PGA)统一调整为0.1g。基于OpenSees分析软件建立了周期分别为1.0、2.0、3.0、4.0、5.0s的SDOF体系,并采用时程分析法研究了其加速度、速度、及位移响应。对基于这些响应的Ds5-95%与CAV、AI的相关性进行了分析。结果表明对于不同周期的SDOF体系,基于加速度峰值响应的Ds5-95%与CAV或AI之间的相关性最好,速度响应次之,位移响应最差,且相较于AI强度指标,Ds5-95%与CAV之间的整体相关性明显较好。表明在进行与结构地震动持时特性的相关研究时,可采用CAV强度指标。此外,建立长周期结构模型会更有利于考虑地震动持时特性的相关研究。

ANALYSIS OF INTENSITY INDICES CONSIDERING GROUND MOTION DURATION BASED ON SDOF SYSTEM

In this paper, 60 ground motion records with different duration are selected from the PEER ground motion database, and their peak acceleration (PGA) are scaled to 0.1g. Taking these ground motions as seismic excitation, the time history analysis of series SDOF systems, molded by seismic software OpenSees, with variable periods, such as 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0s, are performed. Specially, the representative seismic responses such as, acceleration, velocity and displacement were investigated. Then between the Ds5-95% and CAV, AI based on these maximum responses were investigated respectively. The analytical results show that The Ds5-95% has the best correlation with CAV, AI based on acceleration peak response, followed by velocity response, and the displacement response is the worst. And the correlation between Ds5-95% and CAV is significantly better than that between Ds5-95% and AI. It is suggested that the CAV intensity index should be selected in the study of characteristics of ground motion duration for structure. In addition, the structure model with long period will be more conductive to the relevant study considering the characteristics of ground motion duration.