屋盖开孔的近地空间建筑的风致内压

Wind-induced internal pressures in closing-ground buildings with a roof opening

以屋盖开孔的近地空间建筑为研究对象,采用刚性模型测压风洞试验方法,研究了开孔率、开孔位置、内部容积、地貌类别等因素对风致内压的影响规律,与当前主要国家规范及以往试验进行对比。结果表明:屋盖开孔建筑的内压高度相关,内压存在高频Helmholtz共振,角部开孔工况的Helmholtz共振现象明显;屋盖开孔建筑的内平均风压在全风向角下表现为吸力,角部开孔工况的内平均风压较中心开孔工况大;屋盖开孔建筑的脉动内压随模型内部容积增大而减小,随来流湍流度增大而增大,侧墙的门窗开孔可减小平均内压和脉动内压;各国规范均不同程度地高估了屋盖开孔建筑的内部正风压,低估了内部负风压。

Current wind load provisions and existing research about internal pressures of building with a dominant opening mainly focuse on wall opening configuration while seldom pay attention to the roof opening case.The effects of twenty roof opening configurations on the internal pressure were examined using wind tunnel tests for a typical closing-ground building.The configurations examined include the effects of opening locations,opening sizes,volumes of internal spaces,and field configurations.The internal pressures are found to be highly correlated,and there are significant Helmholtz oscillations in the high frequency band for the roof opening buildings.Helmholtz oscillations in the roof corner opening configuration are more significant than that in roof center opening configuration.The mean internal pressures exhibit suction for all the wind angles,while the values of internal pressures for roof corner opening configuration are larger than that for roof center opening configuration.The fluctuating internal pressure will decrease with the increasing of the internal volume of model or with the increasing of the density of turbulence.The mean internal pressure and fluctuating internal pressure are reduced effectively for opening a door or a window on side wall.The positive internal pressure is overestimated and the negative internal pressure is underestimated by the current wind load provisions.