Modeling response spectrum compatible pulse-like ground motion

Abstract

The seismic response analysis of near-fault pulse-like ground motions is severely restricted due to the scarcity of pulse-like records. The requirement in regulations that the response spectra of artificial ground motions should be compatible with the target response spectrum makes the relevant studies more difficult. As a result, this study proposes a trigonometric series-based stochastic method to simulate pulse-like ground motions, with the advantage that the corresponding pseudo-spectral acceleration is compatible with the given target response spectrum. This goal is achieved by two parts. (1) The envelope function of pulse-like records obtained by the Hilbert transform is utilized as the amplitude modulation function to ensure that the simulated ground motion contains a pulse. (2) A novel iteration scheme based on random frequency parameters is proposed to guarantee the response spectrum compatibility. The velocity ground motion is first simulated since the pulse usually exists in velocity. The ground-motion acceleration subsequently obtained by differentiating the velocity is adopted to calculate the response spectrum. Two cases are implemented and verified the effectiveness of the proposed method in enriching existing pulse-like databases and generating pulse-like ground motion in areas that lack records. Moreover, the amplitude modulation function and target spectrum, as two key factors in the proposed method, determines the presence of a pulse and the pulse periods, respectively. This property makes the proposed method potentially universal applicability for stochastic pulse-like ground motion simulation in engineering.