Wind Induced Vibration Analysis In Time Domain And Aerostatic Stability Study For Cable-Stayed Bridge

As we know, the aim of wind induced vibration analyses for a long span bridge is to study its aerodynamic and aerostatic stability and to find its buffeting responses so as to avoid wind instability and to ensure the buffeting amplitude within a permissive range for structural safety and amenity.Although lots of investigations on wind induced vibration analyses for long span cable-stayed bridge have been made, some problems are still not solved perfectly. Firstly flutter and buffeting analysis in time domain for long span cable-stayed bridge requires further investigation and improvement such as that the wind effects of the bridge towers need to be considered and that the statistical estimation method of wind-induced responses need to be improved as well as that parametric study on wind-induced responses need to be conducted more sufficiently. Secondly problems such that a study on aerostatic stability of long span cable-stayed bridge is customarily neglected, etc.In this dissertation, the method of stochastic wind field simulation considering wind effects of the bridge towers is firstly presented. And further a general indicator for estimation of the flutter and buffeting responses in time domain is brought forward. So flutter and buffeting responses analysis for long span cable-stayed bridge can be improved. Furthermore, aerostatic stability analysis for long span bridge is brought into the wind induced vibration analysis system. In view of that there may exist a possibility of aerostatic instability for long span bridge, nonlinear aerostatic stability theory is applied. An incremental double iteration method is used to analyze the nonlinear aerostatic stability for long-span cable-stayed bridges. Based on the above work, a rather systemic 3-D finite element program for wind-induced response analysis program is developed for long span bridges. This computer program has quite strong functions for analysis and has very good developable ability.Hong Kong Ting Kau Bridge is a long span cable-stayed bridge with 3 towers, 4 spans, 4 cable planes and double decks. It is a structure with new design idea and with high flexibility. In this dissertation flutter and buffeting analyses are performed in time domain. And aerostatic analysis for the bridge is also conducted. In this investigation the first emphasis is to study the effects of the geometric nonlinearity, the nonlinear buffeting forces as well as the wind on the bridge towers on buffeting responses of Ting Kau Bridge. The second emphasis is to compare the aerodynamic...