河南电视塔的鞭梢效应分析研究

Analysis and research on whipping effect of Henan TV tower

运用SAP2000软件建立了河南电视塔的杆系三维有限元模型,利用谐波合成法并考虑塔式结构风速谱随竖向变化的特点,模拟了该电视塔多变量互相关脉动风荷载时程曲线,并对该塔整体模型、天线段部分及主体结构部分分别进行了模态分析及风荷载作用下的风振动力响应时程分析。结果表明,附加天线桅杆后,其振动对主体结构的振动形式在低频段影响较小,在高频段该塔的运动形式改变较大,高振型的影响不可忽视;河南电视塔作为一超高全钢结构塔,风荷载作用下动力反应较大,由于天线段高柔,附加天线桅杆后整体结构的自振周期明显增加,从而产生了较强的鞭梢效应,却在一定程度上减小了塔楼的加速度。

A bar system three-dimensional finite element model of Henan TV tower was established using SAP2000 software. The harmonic synthesis method was used to simulate the time-history curve of TV tower＇s multivariate correlated fluctuating wind load, considering the characteristics of the wind speed spectrum of the tower structure changed along the vertical elevations. And the modal analyses as well as wind-induced dynamic response time-history analyses under wind load were carried out on the whole model of the tower, antenna part and the main structure respectively. The results show that the vibration of the additional antenna mast has little effect on main structure＇s vibration form in low frequency band. The vibration form of the tower has larger changes in the high frequency band, so effects of higher mode cannot be ignored. Henan TV tower is a super high-rise steel structure tower, and it has great dynamic reaction under wind load. Due to the high and soft antenna section, the natural period of the whole structure increases significantly with additional antenna mast added, which results in a strong whipping effect and reduces the acceleration of the tower to a certain extent.