Research Of Flutter By Numerical Simulation And Vortex-induced Vibration By Wind Tunnel Test For Flat Steel Box Girder Bridge

China is the world’s bridges superpower, and bridges are important traffic facilities for economic development, it is thus clear that they are in a very important position. Meanwhile modern bridge is to develop increasingly in the direction of large span, light and soft, this has resulted in the wind-induced sensitivity increase, and made the research of wind-induced vibration more important and urgent. The wind-induced vibration of flutter and vortex-induced vibration are investigated in detail, and reference value for practical engineering and relevant research work is provided.A long single span suspension bridge which spans880meters, is taken as an engineering example in this thesis, and on the basis of section model with wind tunnel test, the flutter and vortex-induced vibration characteristics of the main girder have been investigated. CFD (Computational Fluid Dynamics) method is applied to conduct two-dimensional numerical simulation of the main girder, successfully identify eight aerodynamic derivatives related to vertical and torsion. Base on the main girder cross section, the flutter performance of the bridge has been investigated by changing the aerodynamic configuration of the cross section. The research work is mainly focused on the following several aspects:(1) A long span suspension bridge is taken as an engineering example, whose finite element model is established by using the finite element analysis software ANSYS, and then the dynamic characteristics is analyzed.(2) Through wind tunnel test, direct measurement method is used to determine the critical flutter velocities of section model with construction state and completion state at different attack angles, and then the flutter stability performance of the bridge is evaluated. The effects of attack angle, damping and guide vane on the vortex-induced vibration are investigated in detail, the optimization effective aerodynamic measure is presented to reduce the vortex-induced vibration.(3) Flat slab model’s eight aerodynamic derivatives are identified by using the fluid dynamics software FLUENT and numerical analysis software MATLAB, and compared with theoretical solutions of flat slab to verify the validity of this numerical simulation method, and then eight aerodynamic derivatives of this suspension bridge with flat steel box girder are successfully identified. Furthermore, influences of the different computational domain size and vibration amplitude on the identification accuracy of the flat slab model’s eight aerodynamic derivatives are pursued. (4) Influence of the geometrical modifications of flat steel box girder on the flutter stability performance of the bridge section is pursued by CFD numerical simulation method.(5) Finally, the research work which finished in this thesis, is analyzed and summarized fully. Reference value for practical engineering and relevant research work is provided, and the problems need to be perfected and studied deeply in further research are pointed out.