Equipment Of Wind Resistant Test On Long-Span And Wind Resistant Method Through Air-Suction On The Slab

Bridge is an important transportation infrastructure. With the development of the civil engineering science and technology and the development of lightweight and high-intensitive materials, the span of bridges is increasing. The long-pan bridge structure is sensitive under the effect of the wind load because the stiffness and damping of the bridge is decreased. The wind load and wind-induced stability is becoming one of the critical factors that the safety of the bridge is influenced by. Therefore, it is important to improve the wind resistance of the large span bridges.Currently, there are three measures which can be used to improve the wind resistance of the large span bridges. The measures include the mechanical measures, aerodynamics measures and structural measures. Mechanical measures are based on the structure response control. Aerodynamic measures and structural measures are based on the control of the flow around the bridge section. The quality of wind flow around the bridge section can be improved directly by the two measures. The measures based on the control of the flow around the bridge section are researched by the intuitive and effective wind tunnel test. Meanwhile, with the rapid development of the Computational Fluid Dynamics (CFD), the numerical simulation became an important method which can be used to research the flow of the bridge structure.First, according to the test requirements of the wind-induced effect on the bridge and the coupling problem existed in the traditional wind resistance equipment, the decoupling test system was designed in this paper. The system can be used to measure the static and dynamic characteristic of bridges. Therefore, the three components of the static force and the t flutter derivatives and vortex-induced vibration is measured by the system and the measuring results show that the decoupling test system has good effect.Secondly, in order to solve the problem that was low test density and accuracy in the traditional wind field test system, the stereo positioning device used to measure the wind field was designed in this paper. Many positions and high-accuracy of wind field test can be completed be the device.Finally, in the paper with air-suction is studied by the numerical simulation based on Computational Fluid Dynamics (CFD). The research object is a slab model located in an even wind flow field. There is an air-suction hole that is close to the wind inflow on the undersurface of the slab. In order to obtain the wind-included static effect on the slab affected by the steady air-suction, the three components of the static force is calculated in the conditions with the air-suction coefficients and models changing. In simulation the Reynolds Stress Equation Model (RSM) turbulent model is adopted for solving the governing equations. The results show that the drag coefficients decrease observably and the moment coefficients increase. The results also show that the pressures of the windward surface of the slab decrease with more and more suction energy supplying while the pressures of the leeward surface of the slab are almost the same. The numerical results indicate that the steady air-suction can improve the structure of the boundary layer of the wind flow around the slab effectively and reduce the wind-included drag force.