表面粗糙度对超高层建筑风荷载与风振响应的影响

Influence of Surface Roughness on Wind Load and Wind-induced Response of Super-tall Building

为了研究表面粗糙度对高层建筑风荷载与风振响应的影响,选取粗糙条、砂纸两种改变模型表面粗糙度的方法,进行方形建筑刚性模型同步测压风洞试验,获得不同粗糙度工况下模型的表面风压分布特征,在此基础上分析了其气动力系数、气动力功率谱和风振响应.研究表明:高层建筑的表面风荷载与粗糙条的间距、厚度有一定的关系,在突出系数小于0.4%时,影响不明显;砂纸可明显减小中间层迎风面的平均风压、侧风面和背风面的平均风压绝对值,以及脉动风压,但会增大顶部迎风面的平均风压和负压区的平均风压绝对值(影响率均在25%以内);表面粗糙度对顺风向气动力功率谱的影响较小,但会使横风向漩涡脱落的周期略降低(5%以内),涡激力减小.建筑物表面的局部突出在一定范围内可略减小建筑风荷载和风振响应,建筑物表面的粗糙化处理总体上有利于结构抗风.

To study the influence of surface roughness on wind loads and wind-induced responses of su- per-tall building,a rigid model synchronous pressure measurement wind tunnel test of a square building was carried out by selecting two types of surface roughness--rough strip and sandpaper.After the analysis on the characteristics of the wind pressure distribution of the model, the aerodynamic force coefficients, the aerodynamic power spectra, and the wind-induced responses were subsequently analyzed. The results show that the spacing and thickness of the rough strip have a certain influence on the surface wind pressure of the high-rise building, but the influence is not obvious when the prominent coefficient is less than 0.4%; Sandpaper can obviously reduce the intermediate layers-average wind pressures on the windward side and the absolute values on the lateral side and lee side, and the fluctuating pressures, but would increase the absolute values of the mean wind pressures on the top of building （the influence rates are all less than 25%）;The surface roughness has less effect on the along-wind aerodynamic power spectra, however,it would decrease the frequency a little （less than 5G）,and meanwhile reduce the amplitude of the vortex shedding. The prominent objects on building surface in certain thickness range can reduce the surface wind loads and wind-induced responses.The roughened processing for building surface is generally conducive to structural wind resistance.