Abstract:

For long-span bridges, there exists obvious time difference in seismic input among different piers due to different geological conditions of the pier base. Thus, the multi-support excitation effect should be taken into consideration in the analysis of seismic response. In this paper, based on the large-mass method, the seismic responses of long-span bridges under multi-support excitation are analyzed on the platform of commercial finite element program Strand7. Afterwards, the seismic responses of a three-span continuous middle-supported steel arch bridge with a main span of 428m are analyzed under different input conditions such as uniform excitation, traveling wave excitation and muhi-support excitation. The results indicate that the traveling wave excitation and the multi-support excitation should be considered in the seismic analysis because both of them have significant influence on the seismic responses of long-span arch bridges.

Key words: long-span bridge, seismic analysis, uniform excitation, traveling wave effect, multi-support excitation