［摘要］介绍了几种大跨度屋盖结构下压风荷载的计算方法，并以某大型体育场屋盖为例，通过引入峰值因子和位移匹配度判据，分析了等效荷载作用下位移响应值和空间分布的合理性。研究结果表明，按比例放大的阵风荷载因子法和动力放大系数法，当计算基准值较小时，得出的放大倍数过高，将导致除等效目标之外的响应值被高估。采用准静态荷载与均匀分布附加风振力的线性叠加方法得出的等效荷载将给出较为合理的位移响应值，其中又以结合LRC方法的等效荷载位移匹配度最高。此外，研究表明若不考虑风洞试验结果，按体型系数+0.2在半跨屋盖上作用均匀风荷载，也能给出基本合理、工程上可用的下压风荷载。
［关键词］大跨度屋盖结构；阵风荷载因子；动力放大系数；下压风荷载；附加风振力
中图分类号： TU312.1, TU311.3 文献标识码： A文章编号：1002-848X(2011)11-0131-06
Determination method and a case study of the downward wind load acting on largespan roof
Chen Kai, Fu Longbiao, Qian Jihong, Jin Xinyang(CABR Technology Co., Ltd., China Academy of Building Research, Beijing 100013, China)
Abstract: Taking the large roof of a stadium as an example, some methods to determine the downward wind load of large roofs were demonstrated. By introducing the criteria of the peak factor and the response matching factor, it was investigated that if the response values and distribution under the action of the downward wind loads are reasonable. It was shown  that the responses except the equivalent target would be overestimated if the scale factors (such as gust load factor and the dynamic factor) were unreasonably high due to the low reference value. However, the responses were sensible under the action of the wind load obtained by superimposition of the quasi-static wind load and uniform additional wind-induced vibration force. In particular, the downward wind load based on the quasi-static wind load of LRC method gave the best match of the response. Besides, it is suggested that the wind load with a shape factor of +0.2 acting on half of the roof is still practicable download wind load if the wind tunnel results are unreachable.
Keywords: large-span roofs; gust loading factor; dynamic factor; downward wind load; windinduced vibration force
*国家自然科学基金面上项目(50878202)。
作者简介：陈凯（1976-），男，博士，副研究员，研究方向：风工程与荷载，Email：chenk@pku.org.cn。
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