Research Of Dynamic Response Of Continuous Steel Box Girder Under Load Of Vehicle-Bridge Coupling

Bridges under varieties of dynamical loads often occur large deformation and internal force and will seriously affect the normal use of the bridge. The bridge can even occur suddenly collapse in serious cases. The continuous steel bridge has been widely used in cross-line project, urban road construction and urban viaduct because of its light weight, simple construction, innovative design. Such bridge under load of vehicle has arised more and more problems.In order to ensure similar bridges safety and passenger comfort, it is necessary to deeply research the dynamic response of the class of continuous steel box girder under load of vehicle-bridge coupling.This paper selects the City Elevated continuous steel box girder bridge as the research object. Firstly,the vehicle model based on ANSYS platform is established. The road roughness samples are generated depending on the national standard of road spectrum. Loads properties under load of different vehicle speeds and different roads are analysed. Then the vehicle model and bridge model are established. The node coupling method is used to establish time-varying vehicle-bridge coupling system. The calculated vehicle tire load is applied to the bridge structure. The ANSYS parametric design language is prepared for considering the progress of the vehicle enter and leave the bridge. The bridge span displacement and acceleration response are calculated for related conditions in time-varying vehicle-bridge coupling system. Combining with the actual dynamic load test data, the correctness of the model is verified. The dynamic responses of the bridge are analyzed under the different vehicle speeds, road roughnesses, vehicle locations and so on.The main results of this paper are:(1) The half, quarter, mass vehicles model and charpy model are established in the ANSYS platform. The node coupling method is used to establish vehicle-bridge coupling system. The method correctness is verified through previous people’s research.(2) The vehicle model is created. Depending on " Vehicle Vibration Entering-Road Surface Roughness Representation " which is promulgated by nation, the road roughness samples are generated. Loads of different speeds and different road roughnesses are applied to the vehicle model. The characteristic of vehicle tire load under different speeds, different road roughnesses is analyzed in the time domain and frequency domain. The method of determination of dynamic vehicle load is illustrated, when vehicle jumping and braking. Then method for determining vehicle load is proposed in common condition.(3) The bridges and vehicle model are established in the ANSYS platform, using the node coupling method to establish time-varying vehicle-bridge coupling system. The actual measured data verifies the correctness of the vehicle-bridge coupling model. Then the practical method of calculating dynamic response of bridge proposed under load of vehicle-bridge coupling is proposed based on ANSYS platform.(4) The node coupling method is used to establish vehicle-bridge coupling system. The corresponding vehicle load is applied to bridge. The dynamic responses of the bridge under different vehicle speeds, road roughnesses, vehicle lateral positions, vehicle braking are analyzed in time and frequency domain. And then some relevant conclusions are concluded.