强风作用下楔形外形超高层建筑横风效应试验研究

对正方形平面沿高度方向逐渐收缩的楔形外形超高层建筑进行同步测压试验，分析不同高度横风向气动荷载功率谱密度、相干特征、结构基底气动弯矩和相应的风振响应，在此基础上进一步考虑切角对结构气动荷载和响应的影响。研究结果表明：采用锥形外形可有效地消减作用于结构上的横风向气动荷载，并在一定条件下消减结构的风振响应；楔形外形可以抑制漩涡脱落的强度，但不能消除结构的漩涡脱落现象，且会升高结构的漩涡脱落频率并进而升高结构的风致响应；在楔形外形的基础上再进行切角处理可以基本消除结构的横风向漩涡脱落现象；经切角处理后，楔形外形结构的横风向风致峰值基底弯矩在结构1阶模态自振周期6.12~14.28 s范围内基本保持不变；对于锥度η为2.2%和 4.4%的高层建筑，切角处理后其100年重现期的峰值基底弯矩分别比未切角减少31.13%和14.58%。

Experimental research on cross wind effect on tapered super-tall buildings under action of strong wind

The wind pressures on several building models which have different taper ratio (η) of 2.2%, 4.4%, 6.6% and one basic building model of square cross-section were synchronously measured and recorded under the simulated boundary layers representing typhoon wind field using the synchronous multi-pressure scanning system. The power spectrum density (PSD) of the cross wind aerodynamic force (AWAF) at different building height and coherence of AWAF, PSD of across wind aerodynamic overturning moment and wind induced response (WIR) were analyzed in detail. Based on the analysis results the effect of the modification of corner cut on AWAF and WIR were considered. The results show that a tapered tall building may reduce the AWAF and WIR under certain conditions. However, the tapering strategy still can not dispel the vortex shedding and may increase the shedding frequency of the structure, leading to the possible increase of WIR compared with the basic building model of square cross-section. The results also show that the combined strategy of taper and corner cut can effectively dispel the vortex shedding. And the wind induced peak base bending moment (BBM) of a taper and corner cut building keeps basically unchanged when the period of the fundamental mode of the structure ranges from 6.12 s to 14.28 s. With corner cut treatment, peak BBM of the two tapered buildings of η=2.2% and 4.4% can be reduced by 31.13% and 14.58% respectively.