Analysis On Seismic Response Of Long-span Suspension-arch Bridge

Suspension arch bridges as a kind of new structures are combinations of suspensions and arches which are the dorminant components to bear the forces caused in the bridge.This sort of bridges are of to some extend properties of suspension bridges and arch bridges. However,they make behaviors under static and dynamic loads with their complex structure.Thus it is significant to research the bridges' dynamic behaviors when subjected to severe earthquake,and this can be helpful for the new bridge to be constructed.In the essay suspension arch bridges' dynamic properties were studied as follows:1.Responsible formulations were used to describe the bridges' dynamic actions while appropriate method was chosen to solve these problems on the base of forgone researches.2.The finite element model of the structure was formed through reasonable simplification.And modal shapes were studied by using the famous program of ANSYS.3.Long span suspension arch bridges' responses to uniform excitation of earthquake were discussed.One dimension excitation and travalling-wive effect were introduced in this bridges with geometric nolinear being considered.4.Multi-dimension asynchronous excitationes were imposed on the structure and the bridges' seismic response time histories were discussed.Displacement time histories which were used to excite the bridge piers were gotten by twice integral of acceleration time histories.5.As a comparable design project,an arch bridge corresponding to the suspension arch bridge were introduced whose responses to travalling-wive excitationes with geonomic nonlinear being considered.Results from the analysis supplied some useable conclusions for us to make further researches as well as practices.