Based On Three-dimensional Flow Field Span Continuous Rigid Frame Bridge Wind Loads On The Numerical Simulation And Time Domain Buffeting Analysis

With the development of bridge technology,the span of bridge with rigid frame-continuous girder is much more and more longer and the stiffness of such bridge is incessantly declining, so the research on vibration caused by wind also become more and more important. Based on the Tianluo Bridge with main span of 160 meters on wen-fu railway, This paper is carried out to analyze the buffeting of this bridge in operation and longest twin-cantilever stage. The research results of this paper are as follows:1. This paper use WAWS method Proposed by George Deodatis which the Fast Fourier Transform technique is imposed into,the turbulent wind field of tianluo bridge in operation and longest twin-cantilever stage are both simulated and verified by the spectrum and the coherence function.2. According to the theory of CFD, the 3-D wind model of the girder and the pier in tianluo bridge are built by use of FLUENT software which baces on finite volume method. then,their coefficients of three-components of aerostatic force are calculated and the characteristics of these coeffieients are analyzed.3. According to the Scanlan's buffeting model,the buffeting force is timed. By applying two-variable Taylor expansion to the quasi-steady aerodynamic force model, the 12-order element aerodynamic damping matrix and aerodynamic stiffness matrix are derived. So the self-excited forces can be input in ANSYS in form of the element aerodynamic damping matrix and aerodynamic stiffness matrix through Matrix 27.4. The longest twin-cantilever stage and the opreation stage finite element model of tianluo Bridge are established by using finit-e element analysis software ANSYS, then the dynamic characteristic analysis and the time-domain buffeting analysis of thetwo models are carried out. The result shows:Firstly, The longest twin-cantilever stage is more sensitive than the operation stage in the wind-induced buffeting, the longest twin-cantilever stage becomes the most unfavorable stage while anti-wind-induced buffeting. Secondly, the structure responses are significantly greater under the turbulence wind load than under the static force, and it decrease to a certain extent after considering the contribution of self-excited force. Finally, the peak value of the displacement response in the lateral direction and vertical direction of the longest twin-cantilever stage increased respectively by 17% and 18% after taking into account the geometric nonlinearity factor. So It is necessary to consider the influence of the geometric nonlinearity factor while carring out the buffeting analysis.