Field Measurement And CFD Numerical Simulation Of Wind Over Bridge Site With Complex Terrain

The determination of wind characteristics of bridge site is one of important problems in the wind-resistant design of large span bridge, it has critical effects on reasonably determining wind loads and evaluating the wind-resistance performance of bridges. Wind characteristics over bridge site with complex terrain are complex beacuse of the relatively large difference of bridge sites. The research topic on wind characteristics over bridge site with complex terrain has gradually become one of hot issues in bridge wind engineering. Based on the proposed Shanxi Linyi Yellow River bridge project as the background, field measurement and computational fluid dynamics method were used separately to study the winc characteristics over bridge site with complex terrain. The main research works are as follows:1.According to the review of state-of-the-art of field measurement and numerical simulation of wind over the bridge site with complex terrain, the research contents and the research technique route were given on the background of Linyi Yellow River bridge which will be build in the near future.2.Firstly, a brief introduction of Linyi Yellow River bridge was given. Secondly,the scheme of wind filed measurement over bridge site with complex terrain was presented in detailed, including wind measurement tower, anemometers, wind data acquisition and transmission system. Finally, the precision inspection of anemometers and the operation of wind measurement system were introduced briefly.3.The processing methods of wind filed measurement data was introduced briefly.A program was developed with MATLAB to process the field measurement wind data.The mean wind velocity and fluctuate wind were processed with the developed program in present thesis. The parameters of wind characteristics over the bridge site were given. The mean wind parameters, including mean wind velocity, wind direction and wind profile, and the fluctating wind parameters, such as tubulent intensity, gust factors, turbulence integral scale and wind power spectral density, were given separately. The maximum wind speed with 3s time interval and with 10 min time interval at 80 m height of the wind measurement tower are 23.1m/s and 18.3 m/s separately during wind observation; Wind mainly flow from the north by east to south.Index of wind profile is about 0.167, which close to the wind profile index of class B surface. The measured fluctuating wind power spectral density are agree well with the wind power spectral density recommended by wind-resistant design specifications forhighway bridges.4.A brief introdution of computational fluid dynamics was given firstly. The numerical simulation of wind flow over single peak hill was conducted using RNG k-? and SST k-? turbulence models separately. Numerical simulation of wind flow over Linyi Yellow River bridge site was conducted. The influnce of the first thickness and the grid resolution of the meshes on the numerical results were compared with each other. Finally, the wind flow of Linyi Yellow River bridge site from east, sourth, west and north disections were simulated separately with the methods given in present paper. The wind speed distribution laws of the corresponding simulation cases were obtained.