Evaluation and Comparison of New Methods for the Classification of Ground Motions as Pulse-Like or Non Pulse-Like

Pulse-like seismic records constitute a special category of ground motions, since they are capable of causing significant damage to several structures. In this paper the efficiency of two new methods for the classification of ground motions as pulse-like or non pulse-like is investigated. The first method uses the Sd,0(Tp)/CAD parameter and more specifically the ratio of the spectral displacement corresponding to pulse period Tp divided by the CAD (Cumulative Absolute Displacement) of the pulse as an indicator of the existence of a pulse in the velocity time history. The second method uses Mavroeidis and Papageorgiou wavelet for the mathematical representation of the predominant pulse and the cross correlation of the significant pulse and the original record is used as a pulse indicator. It is proven that, for pulse-like ground motions, the ratio Sd,0(Tp)/CAD is around π/4 and the cross correlation is larger than 0.60. The method is applied to a total of 229 records from the NGA database with peak ground velocity larger than 30 cm/sec.