超高层建筑涡激振动若干现象

Some phenomena of vortex-induced vibration in super high-rise building

基于超高层建筑多自由度气弹模型风洞试验测得了横风向风致响应,通过测压试验获得了和振动位移同步的表面风压,借助随机减量法识别了不同折算风速下的气动阻尼,通过位移响应谱和风压谱识别得到不同折算风速下模型振动和流体涡脱的主频率。结果表明:在共振风速附近,气动刚度造成的频率改变量不可忽略,并且结构频率与涡脱频率并不是传统认为的锁定与被锁定关系,而是相互影响、动态近似相等的关系。

Based on multi-degree-of-freedom （MDOF ） aeroelastic model wind tunnel tests for super high-rise bui lding, vortex induced vibrat ion （VIV ） displacement and synchronous wind pressure were measured. The aerodynamic damping at various reduced wind speeds was identified on the basis of random decrement technique. The frequencies of the vibrat ion system and vortex shedding were respectively calculated by the power spectrum of the V IV response andsynchronous pressure. The results show that the aerodynamic stiffness cannot be ignored w ith the reduced wind speed closed to resonance wind speed. More th a n,the relationship between thevibration frequency and the vortex shedding frequency cannot be recognized as a completely interlocked. The vibration frequency may be affected by the vortex shedding significantly when the reduced wind velocity is close to 10. 5, and the system frequency is approximately equal to the vortex shedding frequency.