Research On Application And Vibration Mitigation Performance Of Viscous Damper In Railway Cable-Stayed Bridges

With the development of the transportation, more and more long-span floating system railway cable-stayed bridges, which allow the longitudinal girder swinging to dissipate the vibration energy, have been built. Without longitudinal restraint, the bridge structure would produce large longitudinal vibration displacement of girder and large longitudinal bending moment at the bottom of tower in course of train’s braking, which would affect the normal use and safety of the bridge. In recent years, the vibration control of train braking attracting more and more attentions, has became a focus in current large span railway cable-stayed bridge research. Based on the previous research achievements, and taken the Guipingyu river bridge as engineering background, the thesis has studied the longitudinal vibration control method of the floating system railway cable-stayed bridge while suffering braking force.Firstly, the paper has introduced the dynamic analysis method of bridge briefly, on the basis of certain assumptions, combined with the Guipingyu river steel truss cable-stayed bridge, two spatial finite element model of the bridge has been established by the large finite element analysis software ANSYS, then determined the finite element analysis model by analysis and comparison.Secondly, the paper has studied the mechanical properties of viscous damper, discussed the mechanical characteristic and using range of the commonly used ANSYS damping element, and their advantages and disadvantages, then determined the appropriate damping element introduced in bridge nonlinear vibration control analysis, which also been used in Guipingyu river bridge vibration control analysis;Thirdly, according to the actual practical engineering and requirement of Guipingyu river bridge, the paper has put forward four longitudinal vibration control schemes after discussing the design parameters of viscous damper, meanwhile, the vibration control effect and engineering practical of their own have been analyzed in detail, then the optimal longitudinal vibration control method has been provided. Compared with the undamped scheme, the effect of the optimal scheme is obvious, not only the longitudinal displacement of girder and tower decrease sharply, but also the internal force has been adjusted effectively.Finally, the thesis has investigated and evaluated the shock absorption effect of the optimal system dynamic vibration control scheme when the bridge involved in earthquake effect, and it is proved that the optimum vibration control scheme can reduce earthquake effectively, ensure the safety of the structure.