Dynamic Response Of Elastic Support Bridge Due To Moving Vehicles

Vehicle-bridge coupling vibration is a hot research topic both at home andabroad. Studies in the past normally ignored the influences of the substructure ofbridge and the elasticity of bearing, which simplified boundary condition of bridgeinto rigidity. Large number of research achievements manifest that this simplifiedmethod is applicable and suitable. However, massive construction of viaducts andwide application of rubber bearings have put forward new questions on vehicle-bridgecoupling vibration research: the rubber bearing viaduct has great influence on theelastic supporting effect, and in this kind of vehicle-bridge coupling vibration research,does it suitable to use the method of simplifying boundary condition of bridge intorigidity.Concentrated on this problem, this paper conducts a series of studies.This paper applies large-scale finite element software ANSYS to build structuralmodel of elastic support bridge, and by regulating the K figure of support rigidity,conducts research about the influence of its variation on bridge structural dynamicbehavior. Using ANSYS to get parameters of the bridge, which include naturalvibration frequency, model quality, model rigidity and mode of vibration of bridgestructural mode, apply these parameters into the procedure of vehicle-bridge couplingvibration complied by Fortran language, calculate the dynamic response of theelastically supported bridge under the condition of motor vehicle loading effect, thenanalyze the influence of the speed of a motor vehicle, the flatness of bridge and therigidity of bearing on bridge dynamic response.After analyzing the simply supported beam bridge and continuous beam bridgeunder the condition of elastic support, the main conclusions are as follows:The change of running speed has little influence on the dynamic deflection of thebridge; the different levels of the bridge deck flatness have greater influence on theresponse results of the bridge. This conclusion is in accordance with the result of rigidsupport condition. Elastic support has some influence on bridge under the condition of vehicleloading effect, and the magnitude of the effect is related to the support stiffness of thebridge. When the support stiffness of the bridge is small, the elastic support has a littleinfluence on it, and the method of simplifying boundary condition of bridge intorigidity will still be applicable; when the support stiffness of the bridge is large, theelastic support has larger influence, the method of simplifying boundary condition ofbridge into rigidity will lead to greater deviation, which is not applicable any more.