Integratedcontrolmethod On Earthquake And Typhoonfor Lateral Structural System Ofmulti-Tower Cable-Stayed Bridge

Seismic response and typhoon response of lateral structural system are very complex for multi-tower cable-stayed bridges. In the lateral structural system of multi-tower cable-stayed bridges, relative motion of beam and tower is restricted by wind-resistance bearing generally. Because of the rigid constraint system, the lateral seismic response and the lateral typhoon response of multi-tower cable-stayed bridges are big. In this dissertation, with Jiashao Bridge as engineering background, the characteristic of different tower and beam lateral restraints in the form of multi-tower cable-stayed bridges seismic and typhoon performance is analyzed. For fully free lateral structural system, multiple sets of passive damping control method are given and parity analyzed. Finally by the response surface method and nonlinear constraint optimization algorithm, this article gives damping schemes. The main contents and achievements in this paper are as follows.1. The finite element model of Jiashao Bridge is established based on Ansys, the response characteristics of different lateral structural systems in the effect of earthquake and typhoon are analyzed by the the finite element model. The results show that:(1) In the effect of earthquak, the fully free lateral structural system has large lateral beam displacement but small lateral tower displacement and lateral tower bottom internal force responses. As for the fully constraint lateral structure system, it is just opposite to the above situation:lateral tower bottom internal force responses and lateral tower displacement are large while the lateral beam displacement becomes small. (2) In the effect of typhoon, the fully free lateral structural system has large lateral beam displacement and lateral pier bottom interal force responses but small lateral tower bottom shear force, otherwise the fully constraint lateral structure system has large lateral tower bottom shear force but small lateral beam displacement and lateral pier bottom interal force responses. Besides, lateral tower bottom moment and lateral tower displacement have a little difference between two lateral lateral structural systems.2. Schemes which adapt damping are proposed for fully free lateral structural system, analysis and comparisons of the effects of different damping schemes show that:(1) In the effect of earthquak, of elastic cable and viscous fluid damper that set between tower and girder can significantly reduce lateral beam displacement response multi-tower cable-stayed bridges, but tower bottom lateral internal force responses may be exaggerated, viscous fluid damper is more effective than elastic cable in reducing seismic response. (2) In the effect of typhoon, elastic cable and viscous fluid damper can significantly reduce lateral beam displacement response and lateral pier bottom interal force responses, and also viscous fluid damper can reduce tower bottom lateral internal force responses and lateral tower displacement effectively. In order to obtain significant control effects, the parameters of damping systems should be reasonable. In the integrated use of the elastic cable and viscous fluid damper schemes, two devices can work together to achieve better control effects.3. Response surface method and nonlinear constraint algorithm are used for optimized analysis of lateral structural damping system in the effect of earthquake and typhoon. Damping effect response using response surface method can be used for the seismic and typhoon response of the optimal control design. Optimized results are obtained using nonlinear constraint optimization algorithm through damping analysis. According to the response characteristics and control objectives of multi-tower cable-stayed bridge in the effect of earthquake and typhoon, damping schemes should be improved to reduce the seismic and typhoon responses at the same time of multi-tower cable-stayed bridges in the lateral structural system. The integrated control method of multi-tower cable-stayed bridges in the lateral structural system is obtained in the effect of earthquake and typhoon.