Anti-seismic Performance Analysis Of Long Span Steel Truss Arch Bridge

Steel truss arch bridge is widely used in the flat and open earthquake prone area because of its rigid and flexible structure characteristic.Due to the structural complexity of the steel truss arch bridge,the traveling wave effect and the influence of the bridgetower,the seismic response is complicated.Therefore,it is necessary to study the seismic performance of long-span steel truss arch bridge.This paper firstly briefly introduces the general development situation,the characteristics of long span steel truss arch bridge and the research status of seismic performance.Then,taking a project as the background,the influence of geometric non-linearity under the static condition is analyzed,and the dynamic properties of the structure are analyzed.Finally,the seismic performance analysis of long-span steel truss arch bridge is analyzed by means of response spectrum analysis method,consistent excitation time-history analysis method,time-history analysis method considering traveling wave effect,and fine calculation model considering bridgetower influence.Research findings:The overall stiffness of the steel truss arch bridge is big enough and it can be hardly affected by the geometric nonlinearity,however,the transverse stiffness is relatively small and the transverse seimic response is relatively bigger,we should focus more on strengthening the lateral rigidity in the structure design.The bridge frequency band is narrow,and the coupling between the modes should be taken into account in the mode combination,and the influence of the high-order vibration mode cannot be neglected.When the seismic load is raised from E1 to E2,the stress change of the bar near the arch foot is more significant.In the analysis of seismic performance of long span steel truss arch bridges,traveling wave effect ought to be considered because of its significant influence on seimic response.The bars near the arch foot are more sensitive on traveling wave effect.Due to the coupling effect of longitudinal seismic excitation and vertical excitation,after considering the vertical earthquake,the effection of traveling wave on in-plane bending moment of the vault and arch foot becomes smaller,the effection on out-plane bending moment of arch foot becomes greater.For the sake of safety,the influence of bridgetower and other structures should be considered in the seismic performance analysis of long-span steel truss arch bridges.