基于美标的超高烟囱在高风速下的横向风振分析

Analysis of transverse wind vibration of a tall chimney based on ACI 307-08 under high wind velocity

孟加拉国某烟囱高度为270 m,美标设计风速为80 m/s.超高烟囱在如此高风速作用下是否产生横向风振成为设计关注的焦点.为了解烟囱的风振响应情况,首先按照ACI307-08中计算公式计算顺风向风荷载,并进行了横向风振判定.根据判定结果,本工程烟囱不考虑横向风振.为验证美标的判定结果,本文按照共振理论对烟囱的横向风振进行分析,同时利用Fluent流体软件对烟囱进行CFD数值模拟,从理论上证实烟囱的确会发生局部的横向风振.但考虑该横向风振组合后的风荷载远小于顺风向风荷载,因此,按照ACI307-08规范公式判定本工程烟囱无需考虑横向风振是合理和安全的.

The paper researches the wind-induced response of a 270 m chimney in Bengal under wind velocity 80 m/s.It is the focus that the across-wind load should be considered or not.First the along-wind load is calculated and the transverse wind vibration is judged not to be considered based on ACI307-08.To verify the result,the transverse wind vibration is analyzed using the resonance theory.Fluent is also used for the CFD numerical simulation;It is shown that there will be transverse wind vibration on part of the chimney;but the combination of across-wind and along wind is less than the along-wind load.So the formula in ACI307-08 is reasonable.