屋盖开孔的近地空间建筑的平均风压特征

Mean wind loads on a closing-ground building with a roof opening

对开孔位置和开孔率不同的7个屋盖开孔近地空间建筑进行了缩尺刚性模型测压试验,分析了屋盖升力系数,屋盖中线测点和立墙测点的点体型系数,以及屋盖的块局部体型系数分布规律,并与当前规范取值进行比较,结果表明:屋盖中心开孔减小了屋盖向上的净平均风吸力,屋盖轴线测点最大正体型系数可达+0.32,中心开孔屋盖设计时应充分考虑正风压作用;屋盖角部开孔时的正风压较中心开孔工况大,对结构受力不利;中国规范对于屋盖中心开孔工况的角部块Ra的局部体型系数取值偏于不安全;屋盖角部开孔后局部块受风的压力作用显著,会导致屋盖的进一步破坏;屋盖中心开孔增大了迎风面立墙正风压86%以上,减小了侧墙和背风面立墙的吸力,使得在全封闭状态下承受风吸力的背风面墙转而承受风压作用。

The effects of seven different roof opening configurations on net mean wind loads upon a closing-ground building were examined using wind tunnel tests.The lift force coefficients of roof,shape coefficients of center-line measured points on roof and wall ones,local shape coefficients of roof were specially studied and compared with the values from the present codes.It was shown that the net mean suctions on the roof are reduced for the configuration of roof center opening;the biggest value of positive shape coefficient of roof center-line measured point is ＋0.32,the positive wind pressure should be considered in the design of a structure with roof center opening;the positive wind pressures in the configuration of roof corner opening are larger than those of roof center opening configuration,this situation is unfavorable for structures;the Chinese Code is found to significantly underestimate the local wind pressures of corner area Ra for roof center opening configuration;the local wind pressures for roof corner opening configuration are larger than those of roof center opening configuration,this situation can cause the roof to be further damaged;the positive wind loads on the windward wall increase up to 86% for roof center opening configuration,the suctions on the side wall and leeward one decrease largely.