Intensity measures of pulse-like ground motions in the full periods
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Abstract
Since the traditional ground motion intensity measure (IM) cannot reflect the des-tructive characteristic of the pulse-like ground motion effectively, thus it is crucial to study the pulse-like ground motion’s IM in full periods. In this paper, 236 pulse-like records were selected from the NGA-West2 database, and the similarities and correlativities among the 42 ground motion parameters were studied; meanwhile, the intensity measures of pulse-like ground motion were preliminary confirmed. Secondly, based on the analysis of the dynamic time-history of the single-degree-of-freedom system, the variation features of correlation coefficients between the pulse-like ground motion’s IM and the maximum nonlinear displacement um with period were studied under different ductility μ conditions. The validity of predetermined pulse-like ground motion’s IM were determined by the linear regression and dispersion analysis. Finally, the acceleration response spectrum amplification factor Af was proposed to be the IM parameter considering pulse-like non-station arity, and its validity was further verified. The results show that: ① Sa(T) was more suited to be the IM in the period 0−1 s; ② Sa,avg, Sv,avg, PPV, If and PGV are more suitable as IM than Sa(T) in the period 1−3 s; ③ Sa,avg, Sv,avg, PPV, If, PGV and Sa(T) are not appropriate to be IM in the period 3−6 s; ④ Af is more specifically suitable to be the parameter of pulse-like ground motion’s IM in the period 0−6 s. And when the natural vibration period of the structure was less than pulse-like period, um has the minimum dispersion with the Af as the IM.
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