Vehicle-bridge coupled vibration of highway double-deck steel truss bridge

In order to study the impact effect of vehicle-bridge coupled vibration on highway double-deck steel truss bridge, contact point between wheel and bridge surface was regarded as fringe, vehicle-bridge coupled vibration system was divided into vehicle subsystem and bridge subsystem based on separation method. The motion equations of vehicle subsystem and bridge subsystem were established respectively by using virtual work principle and finite element method. Vehicle subsystem was connected with bridge subsystem through displacement coordination condition and the balance relation of vehicle-bridge interaction at contact point between wheel and bridge surface, and system response was obtained by using iterative method. A highway double-deck simply-supported steel truss bridge was taken as study case, 3D beam grillage finite element model was established by using ANSYS software, and the influences of vehicle speed, bridge damping, bridge surface roughness and different loading modes on vehicle-bridge coupled vibration were studied. Analysis result indicates that there is not very regular function relation between vehicle speed and the impact factor of highway double-deck steel truss bridge. The impact factors of internal force and displacement for all bars become smaller with the increase of bridge damping. Bridge surface roughness is an important incentive for vehicle-bridge coupled vibration, poor bridge surface can make vehicle vibration more intense, and can induce greater impact effect on the whole and part of bridge. When loading modes of single layer and double-layer are different, the whole dynamic responses of bridge change little, the local dynamic responses of bridge are more obvious, so local impact effect should be considered in the design of bridge.