以广州珠江城为例,分析了超高层建筑结构风致振动对于阻尼比和峰值因子取值的敏感性.结果表明:一方面,结构的顶部加速度响应及基底倾覆弯矩响应均随阻尼比的增长呈负指数衰减规律,极端情况下,阻尼比取0.01的加速度响应计算结果比阻尼比取0.04的工况大100%以上;另一方面,由横风向涡激振动引起的基底倾覆弯矩响应对阻尼比的敏感性远大于由顺风向湍流引起的基底倾覆弯矩响应.分析认为:这是由于顺风向湍流引起的基底倾覆弯矩响应很大一部分由平均风荷载贡献,而该部分在计算过程中是按照静力荷载施加在结构上的,不受阻尼比取值的影响.在不利风向角工况下,峰值因子取值在2.5~3.5的范围内变化时,加速度响应及基底倾覆弯矩的变化幅度基本在20%以内.
Pearl River Tower,located in Guangzhou,China,was presented in this paper as an engineering case.The wind tunnel test was conducted based on which the wind-induced responses such as the acceleration response on the top of the building and the base overturning moments were analyzed.Results show that: both the acceleration and the base overturning moments decrease with the growth of the damping ratio,which may be near to a negative function.The acceleration response,when the damping ratio value is 0.01,may be twice as large as that of 0.04.On the other hand,the base overturning response induced by lateral wind vortex is much more sensitive to the damping ratio than that induced by along wind turbulence.It is probably because that part of the latter is contributed by the mean wind which is acting on the structure as static loads and not influenced by the damping ratio.When the gust factor varies from 2.5 to 3.5,the acceleration atop the building and the base overturning moment varies in a limited range not exceeding 20%.