Wind Tunnel Study Of Wind Load Characteristics On Long-span Roofs

Long-span structures have complex shape, are all combination with a variety of surfaces. Due to the long-span structures light deadweight, flexibility, larger span, so that span space structure has become more sensitive to wind loads architecture. And now many countries more and more landmarks are adopted long-span spatial structure, such structures are destroyed under wind load case is not uncommon, the wind effect analysis has been widespread concern. In the current specification, the “Technical specification for concrete structures of tall building”(JGJ3-2010) was introduced in detail in the tall building theory of wind resistance design, still now, a complete design thought of wind load for long-span roof has not been established, just in the wind load distribution has exist many problems, so it is thus necessary to investigate the wind load characteristics of long-span space structure, to be prepared for the wind-induced response analysis. This thesis is supported by National Natural Science Foundation.In this paper, takes the a dry coal shed of one power plant(cylindrical reticulated shell structure) as engineering background. Based on wind tunnel test pressure data, analysis the long-span cylindrical reticulated shell wind load characteristics. Mainly contains:(1)The study of long-span structures roof wind tunnel test and wind loads distribution characteristics. For rigid model wind tunnel pressure test on a cylindrical reticulated shell structure, and introduced its wind tunnel test load profiles, get the surface of structure average wind pressure and pulse pressure distribution, accordingly studied different wind angles, forming a rule characterized by signature turbulent vortex; While using a peak factor method to calculate the structure of the surface pressure extremes, it is concluded that surface structure under wind load, stress the most unfavorable position, provide a reference basis for structure design.(2)The study of on the characteristics of wind load of large span space structure in time domain. In the time domain, used the peak over threshold method(referred POT) to analysis of large span reticulated shell surface wind pressure pulse phenomenon. Draw the windward area measured point pulse phenomenon is obvious, and the testing energy contribution is bigger, in order to achieve the structure safety, this region should strengthen; By the measuring point probability density function, pressure process, the skewness and kurtcsis, studied the non-Gaussian distribution characteristics of the surface structure, and it is concluded that draw non-Gaussian zoning method; At the same time, the correlation between the measured wind load is analyzed, shows that the correlation between measured point decreases with the increasing distance downwind, downwind is larger than cross correlation between wind measuring point.(3)The study of on the characteristics of wind load of large span space structure in frequency domain. In the frequency domain, studied the typical points pulsating pressure power of large span reticulated shell surfaces structure, Pointed out that the wind pressure spectra peak mostly appear in the low frequency; Further analysis of the correlation between measured in the frequency domain, and decreases with measured point increasing distance and the frequency, Downwind to the correlation between the same measuring point is greater than the cross-correlation between wind direction.