切角矩形断面高层建筑风压特性试验研究

Experimental study of wind pressure on high-rise building with cut-angle rectangular sections

针对切角矩形断面高层建筑体型复杂且其风压特性无法通过建筑结构荷载规范直接选取的现状,以某一变宽度切角矩形断面高层建筑为研究对象,在考虑周边复杂建筑风环境的影响下通过刚体模型测压试验研究了建筑模型表面风压系数和体型系数,并讨论了切角矩形断面高层建筑局部风压随风向角和高度的变化规律。结果表明:切角矩形断面高层建筑表面风压特性与常规矩形断面高层建筑基本一致,垂直来流的标准迎风面的平均风压系数为正值,且随着高度增加而增加;斜迎风面与来流方向呈45°时风压系数和规范值差距较大,正负值符号与斜切面与正立面宽度比有关,并给出了最大宽度比为1/8时的取值结果;侧风面和背风面为负压区,背风面平均风压系数约为侧风面的1/2;最大脉动风压和最小平均风压均出现在边角切面处。周边建筑对该高层建筑中下部表面风压的影响较大,个别侧风面受此干扰风压分布无明显规律可寻。

The shape of a high-rise building with the cut-angle rectangular section is very complex.Considering that its wind pressure characteristics cannot be picked from the Load Code for Design of Building Structures,a pressure test on its rigid body model is carried out under a complex wind environment.According to the test results,the surface wind pressure coefficient at the measured points is calculated as well as the shape coefficient.Their variation with the wind angle and height is also discussed.The results show that the surface wind pressure of the section is basically the same as that of conventional rectangular section.Under a vertical inflow,the mean wind pressure coefficient at the vertical windward face is positive and augments with the increase of the height.Meanwhile,there is a big difference between the wind pressure coefficient and its code value of the oblique windward face when the inflow direction is 45 degree.The sign is related to the width ratio of the diagonal plane to the normal face.Also,results are given when the maximum width ratio is 1/8.The cross-wind and leeward surfaces have negative pressure areas,and the average wind pressure coefficient on the leeward surface is about 1/2 of that on the cross-wind surface.The maximum fluctuating wind pressure and minimum mean wind pressure appear at the corner section.The surrounding buildings have great influence on the wind pressure on the middle and lower surface of the high-rise building.However,the distribution of wind pressure on some individual cross wind surface shows no obvious regularity.