| With the huge development of Chinese economic,investment in traffic constructions has enormous increases and bridge constructions tend to have long s-pans and less mass.Many experts give attention to dynamic response to long-span highway bridge when high-speed or heavy-duty vehicles passed.When vehicle pass bridge in high-speed,automobile engine vibration and surface irregularities of the bridge lead to automobile vibration.This vibration is transmitted by contract with tire and surface of the bridge and gives rise to bridge vibration,which leads to the rise of internal force bridge and has adverse influence on structures mechanical characteristics.This is the practical meaning of the research for vehicle-bridge vibration.In this paper,the vehicle system is analyzed by the two axle plane and four-degree-of-freedom vehicle model.With the application of D'Alembert's principle,vibrations equation of vehicle is leaded.Contrast to the vehicle system,the bridge system is analyzed by beam model.the nonlinear dynamic equations of bridge are deduced using force's equilibrium condition and geometrical nonlinearities.Dynamic equation of a vertical-bridge coupling system is proposed by the compatible equation of displacement of the contrast point between the bridge and the vehicle and force equilibrium condition.By Runge-Kutta methods and Visual Fortran program,the displacement response curves of the beam bridge and the curves of impact effect are obtained,which provides a certain theoretical reference for the future design and the prospects for the analysis of the long-span bridge.In this paper,the dynamic response of a five span continuous girder bridge of Dongting Lake Bridge is analyzed by Midas Civil program.The displacement response curves,the acceleration curves and the dynamic bending moment curves under the moving load are obtained,which contrast to the results of Visual Fortran program.It provides evidence for future research. |
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