Nonstationary response analysis of suspension bridges for multiple support excitations

Abstract

A method for the nonstationary response analysis of suspension bridges subjected to earthquake ground excitations at multiple supports is developed. The equation of motion is formulated for the vertical motion of the bridge girder using a continuous co-ordinate system. The nonstationarity of the earthquake excitation is modeled by utilizing a time-varying envelope function. The correlation effects between ground excitations at different supports are investigated, for various cases of traveling seismic waves with different wave propagation velocities. The non-stationary responses are obtained in terms of time-dependent variance functions. Expected peak responses are also evaluated, thereafter. Numerical results from the example analysis indicate that the correlation effects between different support excitations are very significant on the response of the suspension bridge. © 1992.