Non-Gaussian Features Of Wind Loading Pressure On Large Span Roof

With the success of the2008Beijing Olympic Games,2010Shanghai World Expo, and the Asian Games in Guangzhou, urbanization in China is developing at a high speed. The large-span structure is playing an important role in modern buildings, and have a tendency towards larger and more complicated. In order to acquire larger non-column space and overcome constrains on spans caused by gravity of the structure, architects tend to use low-weight and high-strength building materials and highly efficient structural forms. While the weight of the roof is effectively reduced, the stiffness of the structure gets lower and lower. Wind loading has become the main controlling load in the design of the large-span structure. Therefore, the study on the properties of wind loading on the surface of large-span roofs has become an urgent need as an important issue.This paper deals with mean winding and fluctuation winding using data obtained from wind tunnel simulation of flat roofs, dome roofs and arch roofs. It adopts skewness and kurtosis as the basis to decide whether a wind pressure sample is Gaussian or non-Gaussian. Then it makes a comparison with the results acquired from Hinich Test, and finally determines the zones of Guassian and non-Gaussian on the surface of the roofs. The results indicate:(1) For large-span roofs, the wind loading on the surface of the large-span roofs comprises mostly of wind suction force, which is larger in areas such as windward edge and the highest point of the roof. The direction of the wind exerts great influence on wind pressure distribution on the roof, while the distribution is mildly influenced by wind speed, span ratio or surface roughness, i.e., these factors merely alter the quantity of the wind pressure to a small extent, rather than change the pattern of its distribution.(2)When the wind flow encounters a bluff body, it firstly generates great suction force at the windward edge of the roof, then it reattaches on the later part of the body, thus the negative pressure diminishes, and sometimes increases to positive pressure. Consequently, we should take into account the influence of downwind areas in the wind calculations of structures with large-span roof.(3) Due to the influence of signature turbulence, the wind loading on the surface of the large-span roofs in areas of windward edge, edges and corners, and the backward part of the roof (point of reattachment) takes on a conspicuous non-Gaussian property, in consequence, theses areas become critical areas in the consideration of wind loading of structure design.(4) We adopt skewness and kurtosis as the basis to identify Gaussian and non-Gaussian signal:we distinguish between Gaussian and non-Gaussian areas using statistics obtained from wind loading on flat roofs, dome roofs, and arch roofs.(5) Using Hypothesis Testing, when the error probability a=0.05, we examine the Gaussian property of wind loading with Hinich test in the frequency domain using bispectrum. Then we compare the results with the results acquired from skewness and kurtosis testing in the time domain. We compare and synthesize the results of the two tests and finally decide Gaussian and non-Gaussian zones.(6) Considering the possibility of the wind blowing from any direction, we develop the Gaussian and non-Gaussian envelope diagram on flat roofs, dome roofs and arch roofs, and give special consideration to areas with condensed non-Gaussian points such as areas of edges and corners, In this paper, the parameters to locate the Gaussian and non-Gaussian zones are established, i.e., the locating parameters of signature turbulence.