矩形截面高层建筑立面上面风压极值的尺度折减系数

Size Reduction Factor of Extreme Area-Averaging Wind Pressure on Claddings of High-Rise Buildings with Rectangular Section

摘要:

通过一系列刚性模型测压风洞试验，研究了矩形截面高层建筑立面面风压极值的变化特征，并与我国建筑结构荷载规范GB 50009—2012中的相关规定进行了对比，分析了受压面的面积、水平尺度及竖向尺度的影响，给出了更合理的尺度参数。试验结果表明，随受压面尺度的增加，面风压极值逐渐减小，当足尺面积达到50 m²时，面风压正极值的尺度折减系数在0.9左右，而负极值的尺度折减系数在0.8左右。我国建筑结构荷载规范对围护结构风荷载的尺度折减方法将导致面风压极值的低估，尤其是面风压正极值。以作用面面积、对角线长度和宽度作为尺度参数描述面风压极值折减系数的变化规律都不合理，建议采用以受压面的水平尺度b、竖向尺度h和整个建筑迎风面宽度B确定的综合尺度参数（b0.85h0.15/B）来描述建筑立面上面风压极值的尺度折减系数的变化规律。

Abstract:

By conducting a series of wind pressure measurement wind tunnel tests， the characteristics of the extreme area-averaging wind pressures on the cladding of a building with a rectangular cross-section were studied. The test results were compared with relevant standards of Load Code for the Design of Building Structures （GB 50009—2012）. The influence of areal size， horizontal scale and vertical scale of forced areas were discussed， and more reasonable scale parameters were suggested for size reduction coefficients （SRCs） of area-averaging wind pressure. The results indicate that extreme wind pressure gradually declines with the size of forced areas increasing. When the full-scale area reaches about 50 m2， the SRC of positive extreme area-averaging wind pressure is close to about 0.9， while that of negative extreme area-averaging wind pressure is close to about 0.8. The wind-load reduction method of building structure load code in China will lead to an underestimation of wind pressure extreme value， especially in the most unfavorable positive pressure. It is not appropriate to describe the variation of the reduction coefficient by taking the area of acting surface as the size parameter. It is，therefore， suggested that comprehensive size parameters， b0.85h0.15/B， of the horizontal dimension， b， vertical dimension， h， of the acting surface and the width， B， of the windward surface of the whole building be used to determine the SRCs of the surface wind pressure extremum of the cladding.