速度脉冲型地震地面运动强度表征参数评估

Evaluation of intensity measures for pulse-like earthquake ground motions

研究强速度脉冲型地震地面运动强度表征参数(IM)与单自由度(SDOF)体系非线性变形需求的相关性,并分析IM的有效性。采用72条速度脉冲型地震记录,基于SDOF体系的动力时程分析,研究了恒延性水平(μ)和恒强度折减系数(R)条件下脉冲型地面运动IM与最大非线性变形相关性系数的变化规律;通过线性回归和离差分析,研究了加速度反应谱(Sa(T1))和峰值地面运动速度(PGV)作为脉冲型地面运动IM的有效性。分析结果表明,脉冲型地面运动IM对体系周期有很强的依赖性,μ和R对相关性和离散性均有很大影响,Sa(T1)和PGV是相对较优的脉冲型地面运动IM。

The correlation between intensity measures (IM) of pulse-like earthquake ground motions and nonlinear deformation demand of single-degree-of-freedom (SDOF) systems was studied,and the efficiency of IM was described.Based on dynamic time history analysis of SDOF systems subjected to 72 pulse-like ground motions,the variation trend of the correlation coefficient between IM of pulse-like ground motions and the maxium nonlinear deformation demand of SDOF systems with the constant-ductility or constant strength system setting was investigated.Linear regression analyses were performed on these results to identify the efficiency of peak ground velocity (PGV) and spectral acceleration (Sa(T1)) used as IMs of pulse-like ground motion.The study showed that IM of pulse-like ground motions depends strongly on the system's period;ductility level and strength reduction factors have important influence on the correlation and dispersion;and Sa(T1)and PGV are better IMs of pulse-like ground motion.