Dynamic Simulation Analysis For Vehicle-Bridge Interaction On A Simply Supported Multi-T-girder Bridge

When vehicles pass through bridges, they will cause vibration of the bridge, andthe bridge vibration will in turn result in vehicles vibration, leading to a problem ofvehicle-bridge interaction. For the current study on vehicle-bridge interaction,researchers mainly use structural dynamic method to establish differential equation ofmotion, and solve it by numerical integrality. However, this method is constrained bythe number of degrees of freedom of equations of motion. With the development ofcomputer technology and finite element theory, it become possible to establish a morerefined vehicle-bridge interaction simulation analysis system. This paper introduces anew3-D modeling method based on LS-DYNA to simulate the vehicle-bridgeinteraction, aiming at obtaining the actual dynamic bridge response (stress or strain)caused by vehicle action.Firstly, a field test on the approach span of Fifth HuaiHua Bridge(a simplysupported multi-T-girder bridge), located in Hunan. was conducted and introduced inthe thesis. In the test, vehicles passed the test bridge with many repeated runs, andsignificant amount of dynamic data was collected for the significant amount ofdynamic data was collected for the comparison with the simulated calculation results.Secondly, a finite element(FE) model of the whole bridge was established withcommercial software Ansys. The loading condition of vehicles strictly follow theloading cases in the field test. Simulation results exhibited consistency with field testresults. In addition, the calculated modal value which is calculated is similar with themeasured result model calculated and the measured values. Those comparisonsdemonstrate the accuracy of the established FE model. Further, influence lines ofthe test points was obtained based on the FE model.Thirdly, combined with virtual proving ground (VPG) software and finiteelement Pre-processer software Hypermesh, a3-D simulation model was establishedbased on LS-DYNA. The FE model of vehicles included the mass distribution ofvehicle, exquisite wheel model with elastic tires, and suspension systems to ensurethat the FE model can produce the same motivated excitation as the actual vehicle.Moreover, given the vehicle model with different speed, the3-D bridge-vehiclecoupling interaction model was investigated considering the contact dynamiccoefficient of friction resistance between the wheels and bridge surface. Comparison of dynamic response between the test and simulated results demonstrates that bothresults exhibit good conformity for most cases, and the proposed modeling methodcan be used to simulate the vehicle-bridge coupling interaction.Finally, the bridge impact coefficient was investigated by identifying the mostunfavorable bridge dynamic strain value of the corresponding cases with the vehiclespeed varying from30km/h to80km/h in the3-D vehicle-bridge model.