Field Measurement And Numerical Simulation Of Wind On Bridge Site In Mountain Canyon

With the development of the western region in China,promote the Sichuan and Yunnan provinces cross-regional linkage development process,more and more large-span bridges have been built in the complex western mountain canyons;Although the large span bridge on the western mountain canyon area has an important role in promoting the development,but many bridges are built in some areas which have high mountains and deep,special and complex geographical environment has brought a lot of problems to the long-span bridge wind design;Although the bridge structure wind resistance design has the corresponding provisions,but only for the plains and coastal areas have a high reference value,it is a little significance to this complex canyon terrain in western China;So,it is very important to study the characteristics of terrain wind field in mountain canyon.This thesis is based on the study of the crossed the canyon XX bridge which is a part of the Xi-Xiang highway in Xichang Yanyuan County in Sichuan Province.In the bridge area,on both sides of the canyon have erection of a USA YOUNG-81000 three-dimensional ultrasonic wind speed observer,the bridge at the wind environment for long-term field measurement.Through the measured data,The wind angle attack,wind angle,turbulence intensity,integral scale and power spectrum of the bridge are analyzed systematically.The results shows that the overall distribution of wind speed at the bridgehead is small in the morning and large in the afternoon,and the daily winds are above 10m/s,the time period is from 14:00 to 17:00.The wind attack angle is mainly concentrated between ±5°,the wind attack angle is affected by the complex terrain of the bridge.The wind angle is concentrated in the southeast to the south,with the proposed bridge axis angle of nearly 90°,a greater impact on the structure.On the other hand,according to computational fluid dynamics(CFD)knowledge,the SST k-? turbulence model is used to simulate the whole wind environment in the canyon area.According to the wind flow from every 30°divided into 12 working conditions to analysis.The results show that the average wind speed amplification coefficient is 0.78,and the wind attack angle is mainly distributed between-2° and 5.5°.Under the influence of terrain,the wind angle is more than 40° in some working conditions,it is show that there may be oblique wind at the bridge.