Study On Vehicle-bridge Coupling Vibration Response Analysis And Vibration Control Of Twin-I Steel-concrete Composite Continuous Girder Bridge

Twin-I steel-concrete composite continuous girder bridges combine with the advantages of steel and concrete bridge,and the construction process is simple,it is the most commonly used composite form of medium and short span bridges,so they are very widely used at home and abroad.In China,however,the application of the twin-I steel-concrete composite continuous girder bridge is still at its initial stage.At the same time,the moving vehicle load will have a negative impact on the vibration of the bridge.Therefore,the research about the vibration characteristics of twin-I steel-concrete composite continuous girder bridge under the vehiclebridge coupling effect has the very important practical value.The twin-I steel-concrete composite continuous girder bridges are composed of the second stage dead load,concrete bridge deck,I-beams and shear connectors,etc.Therefore,this paper mainly studies each component of the bridge from the following aspects:Firstly,took a twin-I steel-concrete composite continuous girder bridge in China as the research object,and based on the Newmark-β method,the vehicle-bridge coupling model was established by the APDL in ANSYS,which adopted the pointsurface contact mode between bridge and vehicle,and connected the I-shaped steel girder with the concrete slab by node coupling or the spring element,and used the nine degrees of freedom vehicle space model as the vehicle model.The correctness of the model was verified by the field tests.And then,the vibration characteristics of the vehicle and bridge under different stiffness of the deck were analyzed,and the recommended values of the thickness of the deck were given by comparing with the current code.At the same time,the coupled vibration response of vehicle and bridge under different secondary dead loads was studied.In addition,the vertical acceleration response of the bridge under different vehicle weights,vehicle speeds,driving accelerations and road surface levels was analyzed.A tuned mass damper(TMD)was installed in the middle of each span of the bridge to control the vibration of the bridge,and the optimal parameter adjustment method was used to determine the TMD parameters.The vibration response of the bridge before and after the TMD installation was compared and analyzed,and the pedestrian comfort was evaluated with the Sperling index.Finally,the shear connector is an important component of the twin-I steelconcrete composite continuous girder bridge,by simplifying the shear connectors to spring elements placed along the bridge longitudinal direction and replacing the shear force of it with the axial force of spring units,analyzed the force states of all shear connectors in the whole bridge under moving loads,the shear connector mechanical characteristics of the whole bridge under different driving conditions were studied.At the same time,the vibration characteristics of Bridges under different stiffness of shear connectors were analyzed.