复杂塔冠对双塔高层建筑风压特性影响的试验研究

Test investigation on effect of complicated tower top on wind pressure characteristics of a twin-tower high-rise building

利用同步测压风洞试验方法,研究了3种典型风向角下圆角三角形截面双塔高层建筑顶部的花瓣形塔冠对建筑表面风压分布特性和风致响应的影响。基于试验数据,对建筑平均风压和极值风压等值线、整体体型系数、风荷载功率谱密度曲线以及基底合力（矩）进行了分析和比较。结果显示,复杂塔冠在整体上抬高了建筑顶部的风致绕流,使得部分风向角下建筑顶部附近的风压出现增大趋势;塔冠的存在同时使各楼层阻力和升力系数增大,且越靠近顶部增幅越明显;当风向沿着双塔形心连线方向时,由上游塔楼漩涡脱落形成的尾流激振现象十分显著,从而使得该风向角下的峰值加速度和横风向等效静力风荷载均达到最大,而塔冠的存在可能改变横风向风荷载的频谱特性,对于文中研究的双塔高层建筑,塔冠使得涡漩脱落频率略向低频转移,故使相应的峰值加速度和等效静力风荷载有所降低。

Using the wind-tunnel synchronous pressure measurement technique, this paper investigated the effect of complicated tower top on the wind-pressure distribution characteristics and wind-induced responses of a twin-tower high-rise building with a triangular section of rounded corner under three typical wind directions. Based on the experimental data, the mean and extreme wind-pressure contour, global shape factors, wind-load power spectrum curves, and base shear and moment were analyzed and compared. The results indicate that the complicated tower top generally levels up the wind-induced flow around the top of building, which leads to an increase of the wind pressure near the building top under certain wind directions. The presence of the tower top also increases the drag and lift coefficients at each building floor, with the increasing amplitude being more obvious at the floor closer to the top. Under the wind direction along the line connecting of the twin-tower＇ s centroids, the wake excitation induced by upstream building vortex shedding is significant, which makes the extreme acceleration and across-wind equivalent static load reach their maximum under this wind direction, and the presence of the tower top may change the spectral characteristic of the across-wind load. For the current case, the vortex shedding frequency tends to be slightly decreased due to the presence of the tower top, resulting in a small reduction of the corresponding extreme acceleration and across-wind equivalent static load.