大跨悬挑平屋盖结构风荷载特性的试验研究

对一大跨悬挑平屋盖模型进行了比较细致的风洞试验研究,分析了此类结构屋盖的平均局部体型系数和极值局部体型系数的分布特性,研究了均匀和B类两种不同流场对其风荷载分布特性的影响。结果显示结构在均匀流场和紊流的剪切流场所测得的平均和脉动风荷载特性均有显著的差别,文中进一步测量并讨论分析了屋盖上典型测点脉动风压的功率谱密度(PSD)以及空间不同位置之间的相干特性。最后针对此类形状屋面的特点和风压分布特性,提出了一种气动抗风措施,试验结果显示它可以有效削减屋盖风敏感处的风荷载值。

EXPERIMENTAL INVESTIGATION ON WIND LOAD CHARACTERISTICS OF LARGE SPAN CANTILEVERED FLAT ROOF STRUCTURE

The wind tunnel experiment on a large span cantilevered flat roof model has been carried out in this paper. The distribution characteristics for the mean local shape factors and extreme local shape factors of such roof structure are analyzed, the effects for two different kinds stream terrains of the uniform and the exposure category B on the distribution characteristics of the wind loads are investigated. The results show that the wind load distribution characteristics of the roof in the two types of terrains are quite different. Furthermore, the characteristics of the fluctuating omnidirectional wind pressure power spectrum densities (PSD) of some typical tapping locations and the frequency domain coherence properties of the fluctuating wind pressure between different tapping positions at different directions are measured and discussed. Finally, according to the formal features of such roof structure and the distribution characteristics of the wind pressure, an effective wind-resistant aerodynamic measure, which, can effectively reduce the value of wind load on the roof's sensitive locations, is proposed.