Seismic behaviour of cable-stayed bridges under multi-component random ground motion

Abstract

A frequency domain spectral analysis is presented for the seismic analysis of cable-stayed bridges for the multi-component stationary random ground motion incident at an angle with the longitudinal axis of the bridge. The ground motion is represented by its power spectral density function and a spatial correlation function. The analysis duly takes into account the spatial variation of ground motions between the supports, the modal correlation between different modes of vibration and the quasi-static excitation. Using the proposed method of analysis, an extensive parametric study is conducted to investigate the behaviour of the cable-stayed bridge under the seismic excitation. The parameters include the spatial correlation of ground motion, the angle of incidence of the earthquake, the ratio between the three components of the earthquake, the number and nature of modes considered in the analysis, the inertia ratio between the tower and the deck, and the nature of the power spectral density function of the ground motion.