Dynamic Model And Aerodynamic Analyses Of Long-Span Cable-Stayed Bridge With Open Section Girders

Wind-induced vibration has been a key design issue of long span cable-stayed and suspension bridges. The nonlinearity effect on the deformation of the bridge girder will become prominent as the bridge span increases. Therefore, the response of the bridge subject to wind loads will be significant. The wind-induced vibration response of a bridge could be described in either a frequency domain or a time domain. However, the frequency-domain analysis is not effectively reflect the nonlinearity effects of the bridge during the bridge vibration process. The time-domain analysis will be a more effective method to simulate the wind-induced vibration response.The current study focuses on the development of a finite element dynamic model in three dimensions for a long-span girder bridge, an effective stochastic simulation model for turbulent wind field, and a time-domain analysis method for the wind-induced vibration response. The major works include:(1) development of a more effective and practical stochastic wind turbulence model based on the wind spectral characteristics;(2) development of a finite element dynamic model in three dimensions for a long-span girder bridge based on a constraint torsion theory of an open section girder and considering the warping effects of a thin-walled beam;(3) development of a finite element model for the time-domain buffeting analyses Ting Kau cable-stayed bridge using a twin girders model.A finite element analysis program for the simulation of long span cable stayed bridge buffeting response in time-domain has been developed incorporating the above models. Some benchmark examples have demonstrated that the numerical models are quite satisfactory. Then the wind-induced displacement, acceleration responses of Ting Kau Bridge were predicted by using the program. The dynamic characteristics and the relation between response and wind speed were fully investigated.The current study demonstrated that(1) the proposed stochastic wind turulence simulation model is a digitally effective to capture wind spectral characteristics;(2) the proposed finite element dynamic model for a long-span girder bridge deserves higher precision and effectiveness to other beam models;(3) the dynamic characteristics of Ting Kau Cable Stayed Bridge can be effectively simulated by the proposed models;...