Seismic responses of long-span cable-stayed bridges under different patterns of earthquake excitations

In this paper, the methods for the seismic response analysis of the long-span cable-stayed bridges excited by different patterns of earthquakes are built. Taking a cable-stayed bridge with main span of 1018 m under construction as an example, the numerical simulation for the seismic responses of the long-span cable-stayed bridges is performed under the uniform excitation and the travelling wave excitation of the deterministic earthquake or the multi-support excitation of the random earthquake ground motion. The results show that under the excitations, the travelling wave of the deterministic earthquake and the random earthquake ground motion with spatial variability by comparing with the uniform excitation of the deterministic earthquake, the longitudinal displacement of the cable-stayed bridge is clearly decreased, and its vertical displacement at the midpoint of the main span is significantly increased. A conclusion is given that the uniform seismic excitation is not able to control the seismic design for the long-span cable-stayed bridge, and the influence of the travelling wave excitation and the multi-support excitation of the random earthquake ground motion on the seismic responses of the long-span cable-stayed bridge must be considered.