Characteristics Of Wind Load On Long-Span Flat Roof With Opening

In the process of use and construction, opening on the roof is inevitable. Existence of opening will change the flow around the flat roof. This paper is working on the wind load of long-span flat roof with opening of different position and perentage based on the enclosed envelope building and then gives the design value of wind load.1. Wind tunnel experiments of seventeen different kinds of model with opening had been finished.Every model has opening of different position and perentage.2. With the start of distribution of wind pressure, coefficient and spectral analysi, the paper analyzes the mechanism of wind pressure on the upper surface and lower surface of the roof.The results show the signature turbulence on enclosed envelope building, and it changes when there is an opening on the roof. The study found that the influence on signature turbulence by edges of opening is basically same to the edges of the roof, the influence of the opning corner is unique,but when the opening is on center of roof, the influence is not obvious.3. The paper gives the design value of wind load of the main body and the building envelope system.4. Some theories of internal pressure also have been introduced in this paper, especially the governing equation of internal pressure. Two important coefficients in the governing equation had be identified by giving a sine load to the structure at the end of this paper and shows that the value of coefficients is controlled not only by the characteristics of building but also by the characteristics of the external excitation.