Non-stationary structural response with evolutionary spectra using seismological input model

Abstract

A recently developed seismological model of ground motion is incorporated into the non-stationary random vibration theory making use of Priestley's evolutionary power spectral density. A general method of computing the input power spectrum is proposed and shown to reduce to the classical method when the input and the output are taken as stationary. Based on the concepts of Yang's non-stationary envelopes and first-passage reliability estimates via extreme point process, a statistical response spectrum for the pseudo-velocity is developed. Comparisons made among the results of non-stationary analysis with different modulating functions, and that of the stationary approximation, on SDOF linear structures with 5 per cent damping show that the type of modulating function chosen has little effect on the magnitudes of mean pseudo-velocities, provided the input power spectrum is properly scaled, and that the stationary approximation produces conservative results for structures with natural periods greater than 0.5 sec. -Authors