Field Measurements Of Wind Effects On A Low-rise Building During Typhoons

A large number of wind-induced disasters happen in China every year, and the loss caused by typhoons is very huge. Previous wind disaster surveys indicated that the destruction of low-rise buildings were the main constituents of the wind-induced lose. In order to obtain the effective way to reduce the lose of the typhoon disaster on low-rise buildings, research on wind-induced failure mechanism of low-rise buildings is of significance.Many factors influence the wind-induced destruction of low-rise buildings, such as structural strength, stiffness, locations and the characteristics of wind field. Therefore, taking reasonable test is the premise of obtaining reasonable data for research purposes, and is also the foundation of rational design to avoid the destruction.Currently, the main methods to study wind-loads on low-rise buildings are wind tunnel experiment, numerical simulation and field measurement. It is important to verify and validate the results of wind tunnel tests and numerical simulation, since they can not simulate the characteristics of Wind-Field precisely. And field measurement is the most direct and effective method to study the wind loads on low-rise housings. The problem that how to improve low-rise buildings against typhoons is important to the south-east coast area of China. It is necessary to study the wind load characteristics on low-rise buildings more in-depth through field measurement, which is just at initial stage in China. In this thesis, based on a full-scale experimental low-rise building which was built by Hunan University, the characteristics of different typhoons and the wind load characteristics of the low-rise building were analyzed based on the measurement data during four typhoons.Firstly, the wind velocity data of the typhoons were acquainted by three anemometers installed at the height of4.5m,7.5m,10m on a10-meter-high tower which was built near the building. Then, the characteristics of wind speed, spectra, turbulence, gust factor and the relationships between them were analyzed in this thesis. The characteristics of the typhoon generated wind field were summed up in comparison with the characteristics of different typhoons. The results showed that When the wind came from the ocean, turbulence intensity and gust factor changed slightly when the wind velocity varied strongly. When the wind came from the land, turbulence intensity and gust factor decreased with the increase of wind speed. Secondly, the wind pressures were acquainted by various pressure sensors which were installed on the full-scale house to measure the wind-loads on the low-rise building. Then, the distributions of mean wind pressure, peak wind pressure, fluctuating wind pressure and peak factor were analyzed. Lastly, the relationships between wind and pressure spectra were studied. The results showed that the pressures on the roof edge were greater than these on the middle parts. The quasi-steady approach could be used to predict the fluctuating wind pressures in the windward wall, but it failed for theose on the leeward wall. The Cook&Mayne approach can be used to predict the peak wind pressures on the edge and corners of the roof.