风致内外压下圆弧形落地大跨屋盖结构风荷载特性

刘向斌+聂少锋+毛路+曹正霖+孙玉金

摘要：对某墙面开洞的圆弧形落地大跨钢屋盖机场航站楼风荷载特性进行了风洞试验研究；基于计算流体力学软件FIUENT 6.3，采用RNG κε湍流模型对墙面开洞屋盖结构的内外表面平均风压系数分布、分区净体型系数、风速矢量以及风场流迹线等风荷载特性进行了系统研究，并将数值模拟结果与风洞试验结果进行比较分析。结果表明：数值模拟的净体型系数和平均风压系数分布规律与试验结果吻合良好；墙面洞口全开的情况下，由于迎风洞口与背风洞口处压力差的作用，屋盖内表面风压均表现为风吸力，风压分布亦受到洞口的影响；墙面洞口对屋盖上表面平均风压系数分布影响较小；屋盖迎风挑檐区域受到风荷载下顶上吸的叠加作用，最大净体型系数达-2.83。

关键词：圆弧形落地大跨屋盖；风荷载特性；局部开洞；风洞试验；风压系数；体型系数

中图分类号：TU312文献标志码：A

Abstract： Wind tunnel test study on wind load characteristic of circulararc largespan floor roof with local opening of an airport terminal structure was carried out. Based on computational fluid dynamics software FLUENT 6.3， the mean wind pressure coefficient distribution of internal and external surfaces， net shape coefficient of local partition， velocity vector and wind field streamline were systematically studied by numerical simulation with RNG κε model. Then， the numerical simulation results and wind tunnel test results were compared and analyzed. The results show that the net shape coefficient and distribution of mean wind pressure coefficient obtained from numerical simulation agree well with the test results. When wall openings are fully open， there is a pressure difference between windward and leeward opening， so that wind pressure of internal surface is suction and distribution of wind pressure is influenced. Local opening has little effect on mean wind pressure coefficient of upper surface. Because of the combined action of pressure on lower surface and suction on upper surface， the maximum net shape coefficient of windward roof is -2.83.

Key words： circulararc largespan floor roof； wind load characteristic； local opening； wind tunnel test； wind pressure coefficient； shape coefficient

0引言

建筑物在风荷载作用下易产生破坏，尤其是大跨带悬挑的复杂体型结构。各国研究发现，大跨屋盖结构的风致破坏很大程度上是由内外压共同作用所致，因此对其在墙面开洞状态下的风荷载特性进行深入研究对于实际工程尤为重要[15]。

Vickery等[6]对索托体育场屋盖风性质进行了风洞试验，试验表明大部分荷载呈动态性质，这是由于屋盖上部结构形成漩涡使得力在向下部传递时产生竖向波动。Woods等[7]对单面和双面开洞的立方体模型进行风洞试验，研究了不同风向角下单墙面开洞以及前后墙面不同开洞状态对墙面内表面风压分布的影响。……