某会展中心风洞试验研究

通过对某会展中心北侧两个大跨波浪形悬挑屋盖的风洞试验研究,讨论了典型风向下屋盖的平均风压分布,同时对全风向角下屋盖平均风压、脉动风压与极值风压的分布进行了研究,并进一步探讨底部开敞对悬挑屋盖风荷载的影响。试验研究表明:屋盖整体以负压为主,除在迎风向的屋盖悬挑区域外,其他区域风压较小;屋盖局部特殊的体型可能产生"兜风效应",从而显著增大风压;而底部开敞造成的"窄管效应"会显著增大开敞区域的风荷载,同时由于底部开敞减弱了气流的堵塞作用,使屋盖上表面风吸力有所减弱,对下表面风压力影响不大;总体而言,屋盖悬挑端在迎风向的体型系数基本在-1.5至-1.8范围。

WIND TUNNEL TEST OF A CONVENTION AND EXHIBITION CENTER

Based on the wind tunnel test of two long-span waviness cantilevered roofs on the north of a convention center,the mean wind pressure distribution under typical wind direction is discussed.Moreover,the distribution of mean wind pressure,fluctuating wind pressure and extreme wind pressure under the full wind direction are studied.Furthermore,the effect of open bottom on the wind load of cantilevered roof is discussed.The test results show that the roof is mainly presenting negative pressure,and the wind pressure in other areas is very small except for the cantilevered area of the roof under the windward direction.The special shape of the roof may cause "catch the wind" to increase the wind pressure significantly and the "narrow tube effect" caused by the open bottom will increases the wind load in the open area significantly.Meanwhile,since the open bottom weakens the blockage of the airflow,the wind suction on the upper surface of the roof is weakened,but the wind pressure on the lower surface is not greatly affected.The shape coefficient of the cantilevered area of the roof in the windward direction is approximately in the range of-1.5 to-1.8.