Research On Wind Effects Of Long-span Roof Under Typhoon Wind Field

The most important method to study wind load characteristics of long-span roof structures is wind tunnel test. But the wind field simulation objects in wind tunnel test is mainly normal wind such as monsoon. The experiments in recent years show that there is big difference between typhoon wind field and normal wind field, especially the turbulence of typhoon wind field is much higher than that of normal wind field, so it is necessary to conduct tests under typhoon wind field to study typhoon effects on long-span roofs.Based on the tropical cyclone records of Hangzhou, Shanghai, Xiamen and Shanwei meteorological observatory during1949～2012, the key parameters of typhoon were determined using probability statistical analysis and the mean wind profile indexs of typhoon wind field were determined by random sampling method and Yan Meng typhoon wind field model.Take Zhejiang University Gymnasium as the object of research, a rigid model wind tunnel tests under typhoon wind field was conducted, distribution characteristics of mean wind pressure and fluctuating wind pressure under typhoon wind field were investigated. Compared the wind pressure data under typhoon wind field with that under conventional B wind field, typhoon effect on a long-span roof was studied and the distribution characteristics of mean pressure coefficient and fluctuating pressure coefficient were discussed. Under the two wind fields, the distribution of pressure coefficient is similar, but the value of pressure coefficient under typhoon wind field is larger than conventional B wind field significantly:the ratio of mean wind pressure coefficient is1.12～1.38, the ratio of fluctuating wind pressure coefficient is1.68～2.55and the increment of shape coefficient reaches30%.Zhejiang University Gymnasium’s wind tunnel tests under typhoon wind field and conventional B wind field were simulated by large eddy simulation. Numerical simulation results acquired the similar rules as wind tunnel tests, so the numerical simulation method can apply well in the analysis of wind load characteristics of long-span roofs.Compared mean wind pressure coefficients and peak negative wind pressure coefficients of field measurement, wind tunnel test and numerical simulation at110°and120°wind azimuth, the distribution characteristics of pressure coefficient were discussed. The distribution of pressure coefficient is similar, but the value of pressure coefficient under typhoon wind field is larger than conventional B wind field significantly and is more close to field measurement’s value. Therefore, wind tunnel test under typhoon wind field is meaningful to long-span roof structures.Shape coefficient distribution characteristics of typical spherical shell and flat roof under typhoon wind field and conventional B wind field were studied by large eddy simulation. According to the results of statistical data, shape coefficient distribution characteristics were meticulously analyzed.