某骨架支承式膜结构屋盖的等效静力风荷载研究

Investigation of effective static wind loading of open roofs located in city center

以郑州大上海步行街中心广场膜结构屋盖为工程背景,进行了刚性模型的同步测压试验。研究了屋盖表面风荷载分布规律和屋盖的风致响应;采用阵风荷载因子法和荷载响应相关法,研究了屋盖的等效静力风荷载,并分析了两种方法的优缺点。结果表明,城市中心的开敞式大跨度屋盖结构的风荷载以脉动风荷载为主;其风致响应也以脉动响应为主;阵风荷载因子法在以脉动响应为主的情况下定义等效静力风荷载存在困难,荷载响应相关法能克服阵风荷载因子法的这些缺点。

Wind loadings of open roofs located in city center are complicated due to the disturbances of surrounding buildings and the open properties themselves. Take an open membrane roof, which is over the central square of Great Shanghai Pedestrian Street in Zhengzhou, as an example, a wind tunnel test with a rigid model was carried out. The characteristics of the wind loading on the roof surface are particularly investigated. A finite element model is established to run a transient analysis with experimental data, in which the wind induced responses were obtained. Gust loading factor method and load-response-correlation method are both adopted to investigate the unfavorable distribution of wind load, i.e. effective static wind load, and the advantages and disadvantages of both methods are analyzed in detail. The results show that the fluctuating components of wind load and response are much greater than their average components, respectively. There are several misunderstandings for the gust loading factor method when the fluctuating responses are predominant, whereas the load-response-correlation method can overcome the disadvantages of the gust loading factor method.