Span Continuous Rigid Frame Bridge Wind Load Of Numerical Simulation And Spatial Wind Induced Response Of The Study

As to the large span prestressed concrete rigid frame bridge with high flexible twin piers, wind loads should be considered as an important factor with regard to the balanced cantilever construction method during the erection stages. Furthermore, the longest double cantilever erection stage is the most disadvantageous wind-resistant condition.Based on the Tianluo Bridge with main span of 160 meters, the wind field model is built which takes into account all wind effects caused by the mean wind velocity, the three turbulence components and the vortex shedding. Then the computation methods for the wind loads and relevant responses are obtained and applied in the Tianluo Bridge. The research results of this paper are as follows:1) The development of the wind-resistant theory of bridges is introduced, and then the wind-resistant specifications of four nations including China, America, Britain and Japan are compared. Finally, the development of the wind effects' research on the balanced cantilever erection stage of several countries is summarized and concluded.2) Based on the improved WAWS method proposed by Professor George Deodatis of Princeton University, the turbulent wind velocity fluctuations in the inflow and caused by the vortex shedding are simulated and verified by the spectrum and the coherence function.3) The 3-D wind field computation model is built according to the characteristic of the Tianluo Bridge and the formulae of 3-D wind loads are deduced.4) According to the theory of CFD (Computational Fluid Dynamics), the coefficients of three-components of aerostatic force are calculated by use of the Flotran program in ANSYS software and the characteristics of these coefficients are analyzed. Finally, the distributions of the 3-D wind loads of the pier and the deck are obtained.5) The response of mean wind velocity and the background response of the turbulent wind are analyzed adopting the influence function method; and the resonant response of the turbulent wind is given by considering several main mode shapes. Then the relationship among the background response, the resonant response and the maximum response is established by the peak factor.6) The internal forces' responses at the left pier base under 3-D wind loads of the longest double cantilever erection stage of the Tianluo Bridge are calculated. The application points out that it's quite necessary to fully take into account the 3-D wind-induced effects.