摘要
为研究龙卷风对建筑结构的作用特征,在综合分析龙卷风袭击建筑物时高速风冲击作用和突然气压降作用的基础上,提出了封闭结构龙卷风荷载的计算方法。从柱面坐标下的流体力学控制方程组出发,发展了考虑气压降的三维龙卷风风场模型。采用计算流体动力学(CFD)方法对某大跨穹顶结构周围风场进行数值模拟,得到了结构的压力系数,同时计算得到了该结构的龙卷风荷载时程,利用时程分析方法对结构进行龙卷风作用下的风致动力响应分析,得到了结构在龙卷风作用下的位移时程。研究结果表明:龙卷风的袭击过程持续时间短,120 m跨穹顶结构在F3级龙卷风作用下,整个袭击过程仅持续约15 s;龙卷风的作用剧烈,穹顶结构的位移最大值达到2.73 m,远大于规范限值的1/250跨度(0.48 m)。
Pressure distributions and wind-induced responses of a large-span roof in tornadoes were studied. The impact of very high speed winds and the effect of the pressure drop when a building was hit by a tornado were investigated. Based on this, a calculating method for tornado-induced loads on closed structures was presented. The pressure coefficients on a large-span roof were obtained by CFD simulations. The wind-induced responses of the large- span roof were investigated using the time history analysis method. The numerical results show that the attack of F3 tornado lasts only 15 s. The maximum displacements reaches 2. 57 m, which is much larger than 0. 48 m, the standard limit of 1/250 of the span.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2012年第3期104-110,共7页
Journal of Building Structures
基金
教育部博士点基金项目(20070286017)
关键词
龙卷风风场模型
龙卷风荷载
封闭结构
气动响应
tornado model
tornado-induced wind loads
closed structure
aerodynamic response
