高低跨柱面屋盖的风荷载特性研究

Wind loads on an unequal-height double-span cylindrical roof

区别于标准等高柱面双跨屋盖的风荷载特性,不等高屋盖之间形成较强的干扰作用,形成特有的分布形态和数值。针对高低跨柱面屋盖结构,采用风洞试验方法进行测压试验,获得全风向角下的测压数据,并对典型风向角下的平均风压、脉动风压和全风向极值风压的分布特性进行分析。结果表明,尽管屋盖表面平均风压以负压为主,但是受到屋盖高跨部分与低跨部分相互之间的干扰效应,生成区别于等高柱面双跨屋盖的气流分离与再附效应,特别对于檐口、屋脊及屋檐角部位置,会出现负压极值乃至局部负压梯度极值。

Different from the normal wind loads characteristics of equal-height double-span cylindrical roofs,strong interference effects are generated around the unequal-height roofs. Unique pressure distribution patterns and values exit on the roof surfaces. Aiming to one kind of unequal-height double-span cylindrical roofs,wind tunnel test method was adopted to obtain pressure measurement data along all wind directions. Moreover,the mean wind pressure,fluctuating wind pressure and extreme wind pressures characteristics were achieved. The results show that although the mean wind pressure on unequal-height double-span cylindrical roofs surface are mainly negative pressure,the mutual interference effects between the two cylindrical roofs can cause corresponding separation and reattachment flow around the roofs. Especially in the eaves,roof and corner areas along the streamwise wind direction,the extreme negative pressure exists and its gradient changes greatly.