NONSTATIONARY SEISMIC RESPONSE OF MDOF SYSTEMS BY WAVELET TRANSFORM

A wavelet-based formulation has been presented in this paper for the s tochastic analysis of a linear multi-degree-of-freedom (MDOF) classica lly damped system subjected to earthquake ground motion. The ground mo tion has been modelled as a non-stationary process (both in amplitude and frequency) using wavelets. Closed-form expressions of the moments of the instantaneous Power Spectral Density Function (PSDF) of the res ponse have been derived and used to predict the statistics of the resp onse peak of any desired order. For illustration of the formulation, a n example torsionally coupled multistoried building has been considere d along with the twenty synthetically generated time-histories corresp onding to an example ground motion process. (C) 1997 John Wiley & Sons , Ltd.