Wind Tunnel Experimental Investigations On Characteristics Of Wind Fields On Bridge Sites With Simple Forms Of Mountains

In recent years, there have been built lots of long-span bridges in the mountain areas. For the long-span bridges, the wind loading is very important and even control the structure design. The accurate determination of the characteristics of wind field in mountainous area plays an important role in wind resistant design of long-span bridges for both construction and operation stages.The wind field characteristics of eight typical simple two-dimensional hills, the effects of different wind yaw angles and the interference effect of multiple mountains are investigated by using wind tunnel tests in this article. The major contents and conclusions of the researches are as follows:(1) The first chapter introduces the research status of the wind field characteristics in mountain areas at home and abroad from the wind tunnel test, numerical simulation and field measurements three aspects. And then introduces the contents and significance of the article.(2) The second chapter describes the research contents and several related theories of the average wind and fluctuating wind characteristics. And it provides theoretical support for the later research.(3) The third chapter introduces the test model, the test plan, the test cases and the data processing method. And the test errors are analyzed.(4) The forth chapter investigates the wind field characteristics of a single semicircle hill, different kinds of hills and the effects of different wind yaw angles. It shows that, for the impact of the wind field characteristics in front and behind of the hill, the triangle and trapezoid hill is bigger than the semicircle hill, and the bigger the slope, the greater the impact, mainly in the more significant wind barrier effect, the larger wind attack angle and the turbulence intensity.(5)The fifth chapter investigates the interference effect of multiple hills, and puts forward several suggestions on wind resistance design and research of bridges in mountainous terrain. It shows that, when two hills twice the height of the mountain apart, speed-up effect is less, the wind barrier effect is greater than that of a single hill, the wind speed standard deviation and the wind attack angle are greater in the lee side foot. And the wind barrier effect of triangle hills is greater than the semicircle hills. When two hills some distance apart, the wind speed decrease, the wind attack angle increase and the turbulence intensity in front of the second hill. (6) Finally, the related conclusions are summarized and the prospects are addressed.