| ABSTRACT:Cantilevered grandstand roofs are widely used in large buildings w ith large-span and lightweight materials. For this reason, they are a kind of typic al wind sensitive structures. The roof is often installed with complex architectural style such as ribs and wavy surface in order to enhance the performance art of the force of the building. Wind tunnel model test is the primary means to resea rch the wind loads of large-span roof, it is difficult to accurately simulate the su rface of the roof. The engineer is in urgent need of estimating the effect of ribs and wavy surface on wind loads of roofs.In this paper, cantilevered roof is the main research target to explain the me chanism and the number of law of wind loads, combined with two engineering e xamples, a design recommendations were givien.The major research contained are as follows:1. A series of wind tunnel model tests were carried out, the ratio of the ca ntilevered roof model was3:1and design the architectural style of ribs and wav es on the model, rib height and spacing ratio:1:6,1:3,1:2, corrugated vector heig ht and spacing ratio:1:2,1:3,1:4;2. Based on the results of wind tunnel experiments, the characteristics of th e wind pressure on the upper surface and lower surface of roofs were discussed, including the effect of ribs and waves of wind loads, the result shows:The im pact of ribs about flow separation is very small, the wave affects the surface of the roof spoiler separation, the pressure of crest is larger than the trough of wa ve.3. Throughing the wind load coefficient to describe the effect of ribs and w aves. The result shows:at the most important wind direction(perpendicular to the roof edge to the flow, the effect of ribs on uplift of average of uplift of roofs is small, but the fluctuation of uplift coefficient reduced by18.7%, and this tren d does not change with the height of ribs. The average of uplift coefficient incr eased16%, and this trend does not change with the increase of distance of w aves. |
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