正六边形超高层建筑横风向气弹效应研究

Crosswind aeroelastic effects of super high-rise building with hexagonal section

为研究正六边形超高层建筑横风向风致响应和气动阻尼比,开展了一系列多自由度气弹模型风洞试验。测量模型顶部风致位移和加速度响应,基于随机减量法识别了横风向气动阻尼比。结果表明,在顶角迎风时,正六边形超高层建筑易于出现大幅涡振现象,在立面迎风时没有出现涡振现象。顶角迎风时,横风向气动阻尼比随折算风速增大呈现出"先增大到最大正值、再迅速转为最小负值,再平稳回升到零值附近"完整过程。而立面迎风时,横风向气动阻尼比与折算风速近似呈线性关系。最后,建立横风向气动阻尼比的经验评估公式。相关研究可为正六边形超高层建筑的抗风设计和规范完善提供参考。

In order to study crosswind response and aerodynamic damping ratio of super high-rise buildings with hexagonal section, a series of wind tunnel tests for multiple degrees-of-freedom（MDOF） aeroelastic models were carried out. The wind-induced displacement and acceleration response at the top of the models were measured, and the crosswind aerodynamic damping ratio was identified by the random decrement technique. The results reveal that vortex induced vibration（VIV） phenomenon may easily appear when the wind attacks one corner of the hexagonal building, while there is no VIV phenomenon when the wind attacks one facade of the hexagonal building. When the wind attacks one corner, crosswind aerodynamic damping ratio may experience a complete process of firstly increasing to the maximum positive value, and then quickly decreasing to the minimum negative value, and next increasing slowly to the vicinity of zero with the increase of reduced wind speed. When the wind attacks one fa？ade, a linear relationship between the crosswind aerodynamic damping ratio and the reduced wind speed can be observed. Finally, the formula of crosswind aerodynamic damping ratio is established. This study can provide references for wind resistant design and standard improvement of super high-rise building with hexagonal section.