矩形高层建筑气动基底力矩系数研究

Aerodynamic base moment coefficients of rectangular high-rise buildings

摘要:

为探讨长宽比和来流湍流特性对矩形高层建筑基底力矩系数的影响,对长宽比为1/9~9的矩形高层建筑在4种风场下进行了同步测压风洞试验。将试验结果与以往文献数据进行了比较,分析了建筑长宽比、湍流强度和湍流积分尺度对顺风向基底力矩系数平均值与标准差、横风向和扭转向基底力矩系数标准差的影响。结果表明:当建筑长宽比不大于3时,顺风向基底力矩系数平均值和标准差随长宽比先增大后减小,当长宽比大于3时,该平均值和标准差基本不随长宽比变化；横风向和扭转向基底力矩系数标准差均随长宽比增大单调增大,但前者的增长速度随长宽比增大逐渐减小,而后者的增长速度随长宽比增大仍逐渐增大；对于顺风向基底力矩系数,增大湍流积分尺度会使平均值和标准差增大,而增大湍流强度会使平均值减小,标准差增大；对于横风向和扭转向基底力矩系数标准差,湍流积分尺度和湍流强度的影响随长宽比的不同而不同。基于分析结果,针对不同风场提出了矩形高层建筑顺风向、横风向和扭转向基底力矩系数的拟合公式,可为结构设计和荷载规范修订提供参考。

Abstract:

The effects of side ratio and incoming flow turbulence characteristics on base moment coefficients of rectangular high-rise buildings were investigated. Synchronization pressure wind tunnel tests for high-rise buildings with side ratios ranging from 1/9 to 9 under four terrain categories were conducted. The wind tunnel test results were compared with the data in previous literature. The effects of side ratio, turbulence intensity, and turbulence integral length scale on mean and standard deviation values of base moment coefficients in along-wind direction and standard deviation values of base moment coefficients in across-wind and torsional directions were analyzed. Results show that when the side ratio was not larger than 3, the mean and standard deviation values of base moment coefficients in along-wind direction first increased and then decreased with the side ratio. When the side ratio was larger than 3, the mean and standard deviation values of base moment coefficients in along-wind direction did not change with the side ratio. The standard deviation values of base moment coefficients in across-wind and torsional directions increased monotonically with increasing side ratio; the growth rate of the values in across-wind direction gradually decreased, while that in torsional direction increased with increasing side ratio. For the base moment coefficient in along-wind direction, increasing the turbulence integral length scale would increase the mean and standard deviation values, while increasing the turbulence intensity would decrease the mean value and increase the standard deviation value. The effects of turbulence integral length scale and turbulence intensity on the standard deviation values of base moment coefficients in across-wind and torsional directions varied with side ratio. On the basis of the analysis results, the fitted formulas for the base moment coefficients in the along-wind, across-wind, and torsional directions of the rectangular high-rise building under different terrain categories were proposed, which can provide reference for structural design and load code revision.