The Research Of Dynamic Performance For Long Span Concrete Cable-stayed Bridge

Cable-stayed bridge is a combination system and has many advantages,such as longspan,attractive appearance,momentum of the grand,stable performance. The appearance ofcable-stayed bridge injected new vigour into the development of the world bridges. Due to itsmany advantages,cable-stayed bridge has made rapid development in the past50years.now,cable-stayed bridges are being designed to the direction of long span. Comparedwith other forms of beam bridges, the cable-stayed bridges have their own dynamiccharacteristics caused by wind, earthquake and moving motor load. So it is important tosearch dynamic analysis of cable-stayed bridge.In these thesis,on the basis of existing data collected of cable-stayed bridges anddynamics, marshal the analytical method and finite element numetical analysis method ofcable-stayed bridges simply.Taking the example of a certain cable-stayed bridge, establish3-D finite element model of it with software ANSYS, Research self-vibration of the bridgeand detailed describe dynamic characteristic,and the effects on natural vibration of the initialcable force and the density of cable-stayed ropes and cross section stiffness of the cable towerare analyzed.During transient dynamic analysis,assign the uniform moving vehicles lode withwheelbase and plus them to deck, the time history responses of the structure under uniformvelocity moving load are analyzed, and the anplification coefficients of deflection and internalforces of the structure are intensively analyzed. The result indicates some conclusion asfollows: The vibration of superstructure is fierceness and the higher moving speed the fiercerof the vibration. Through a constant impact load of short duration at middle of the mid span,the time history responses of the structure under impact load are analyzed. The result indicatethat when the phenomenon that uneven bridge floor causes vehicle jumping is unfavorable forthe deformation of the structure, if value of coefficient of impact assume according to thecurrent specifications in design of the cable-stayed bridge, some cross sections will be liableto unsafe.