Wind Tunnel Tests And Modeling Of Wind Loads Of Cantilevered Stadium Roofs

The cantilevered roofs of large stadiums are typical long-span structures, because of its large aspect ratio, light weight and being flexible, the wind load becomes one of the most important loads which is considered in the design. Due to the information in wind loading code is insufficient, it can not fully meet the needs of engineering designs, therefore wind tunnel tests are needed to get some necessary information of the surface loads. The aim of this paper is to study the wind load characteristics of stadium cantilevered roofs by wind tunnel tests, which can provide references for practical engineering designs.Firstly, the background of studies of the characteristic of wind loads on cantilevered roofs was reviewed systematically. Then, a series of wind tunnel pressure measurement tests of a typical rectangular rigid scale model with aspect ratio of 3:1 were carried out. Base on the results of the tests, this paper gave a deep discussion on the characteristics of the wind pressures on the long-span roof. Finally, a design recommendations for shape factors of wind load and spectrum models of the fluctuating wind pressure were given. The major research contained are as follows:1. A series of wind tunnel model tests were carried out, the aspect ratio of the cantilevered roof model was 3:1, the high-span ratios were 1:1 and 1.2:1, the roof pitches were 0°,5°and 10°the venting ratios at the rare of the grandstand were 0% ~30%, the terrains were A, B, C and D, totally 32 cases;2. This paper compared several interpolation algorithms for dealing with the data of bad taps and generating the time-history of wind pressure value at any position, from which the v4 method was more suitable;3. Based on the tests results, the characteristics of the mean wind pressure on the cantilevered roof were discussed, including the effects of different inflow roughness, roof pitches and venting ratios above the grandstand, and determined the most important wind direction, then gave the local shape factors at the most important wind direction(perpendicular to the roof edge to the flow), established a more precise calculation of the mean wind pressure model, providing a reference for engineering design; 4. For the distribution of fluctuating wind pressure, this thesis also discussed the effects of wind directions, roof pitches and venting ratios above the grandstand. And the wind fluctuating pressure characteristics of higher than second moments were analyzed, then the criteria to separate the Gaussian/Non-Gaussian was obtained;5. This paper also discussed the characteristics of fluctuating wind pressure spectrums at the most important wind direction, including the effects of the inflow terrain, roof pitches and venting ratios above the grandstand, then gave the model of wind pressure spectrum, simultaneously observed and studied the spatial correlation of different taps on the axis of the roof with different roof pitches, then gave the cross-spectrum model for further structural analysis of wind-induced response, extreme wind pressure and fatigue.