The Seismic Response Analysis Of The System Composited By Self-Anchored Suspension Bridge And Deck Arch Bridge

The composite system made up with a self-anchored suspension bridge and a deck arch bridge is a new system in research, which regards the main cable and arch as the main components bearing loads. It is a novel structure and has an attractive appearance. As a composite system made up with a self-anchored suspension bridge and a deck arch bridge, it has some mechanical properties same as what the other two systems have, while because of its spatial complexities, it has some differences from the others. At present, studying its static and dynamic characteristics is the problem which needs to be resolved immediately, the research on its seismic response analysis has become a top priority.This paper took Yellow River Bridge in Taohuayu Zhengzhou as the background, in order to study the respective characteristics of the three bridge systems under seismic forces, and to get the conclusions that how Traveling wave effect and Site effect influent the seismic responses of long-span bridges and finally to provide some reference for similar seismic designs in future.In this paper, the finite element software MIDAS CIVIL was taken as a tool, using response spectrum and time history analysis methods to calculate the seismic responses of the three bridge systems under the different seismic conditions.The respective characteristics of theirs were summed up by analyzing the results, and the conclusion was gotten by comparring the respective characteristics of theirs that the seismic performance of the bridge tower of the comosite sysytem is better than that of the self-anchored suspension bridge, and its stiffening girder is less likely to drop than that of the self-anchored suspension bridge, while the seismic performance of its arch is worse than that of the single deck arch bridge.The influence of Traveling wave effect to the seismic response of long-span bridges was taken into account by traveling wave method.The conclusion was gotten that the effect of Traveling wave effect on the seismic response of the long-span composite system and arch bridge can not be ignored under the spatial earthquake.Multi-supports non-uniform excitation method was used for considering the effect of Site effect on the seismic response of long-span bridges. Through the calculation and analysis, it is known that Site effect should be considered when the two sides of the three types of long-span bridges are under different geological conditions.Finally, the seismic response of the composite system was studied through multi-supports non-uniform excitation method when both Traveling wave effect and Site effect were on it simultaneously.The result shows that the impacts of the two characteristics of ground motion spatial variation on the seismic response of structures can not be simply superimposed.This paper has shown the respective characteristics of the three bridge systems under seismic forces, explored the influences of the spatial variabilities of ground motion to their seismic responses and provided some reference for similar seismic designs in future.