Stochastic response to earthquake forces of a cable-stayed bridge

Abstract

Stochastic methods of dynamic response are applied to the earthquake analysis of cable-stayed bridges. Certain types of bridge model with fan configuration and A-type towers are used as an example. The input ground acceleration used is that of the Pacoima dam record of the 1971 San Fernando earthquake. It has been shown that the stochastic method gives practically acceptable abstract information such as mean-of-maxima values for vertical displacements at the deck and cumulative probability functions for vertical displacements at mid-main span of cable-stayed bridges. Mean-of-maxima values for bending moments at the bridge deck have also been presented. All the results obtained by the stochastic method have been compared with absolute maximum values by the complete quadratic combination method and time-history analysis. Since the calculation of the spectral density of filtered white noise is relatively simple, the particular form proposed by Kanai for representing earthquake ground acceleration has also been used in this paper for comparison with the actual earthquake record. It gives satisfactory results for cable-stayed bridges.