气动外形对高层建筑风荷载的影响研究

Research on aerodynamic shape effects on wind load of high-rise buildings

针对我国现行建筑结构荷载规范规定的削角和凹角两种角沿修正形式,进行了7种截面形式高层建筑模型的风洞测压试验。定义角沿修正比为单个角沿沿主轴方向投影长度与全截面在同一方向投影长度之比,分析了角沿修正比对建筑风荷载的影响。试验结果表明:截面采用角沿修正是减小矩形截面建筑顺风向和横风向风荷载的有效方式;截面采用角沿修正比为10%的凹角修正时,建筑顺风向风力系数平均值和均方根值降低最多;截面采用角沿修正比为20%的凹角修正时,横风向风力系数均方根值降低最多;从频域来看,角沿修正对顺风向风力功率谱影响不大,而随着角沿修正比的增大,横风向风力功率谱谱峰对应的折算频率将向高频部分移动。

Seven building models with different shapes were designed to test in wind tunnel according to two corner modification forms provided in Chinese load code. The paper defined comer modification ratio as the ratio of projection of single modified comer along the principle axis to projection of the whole section in the same direction. And the influence of comer modification ratio on wind loads was analyzed. The results show that the chamfered corner and comer recession both reduce wind loads on the buildings. While the modification ratio of corner recession is 10% , the mean value and root mean square value of along wind force coefficient are most decreased compared with other models ; while the modification ratio of comer recession is 20% , the root mean square values for the across wind load is the lowest of all test models. In the frequency domain, corner modification has no apparent influence on along wind load but obvious shifts of the peak reduced frequency with increase of comer modification ratio can be found.