广州新电视塔透空区外筒群柱面外稳定承载力与设计方法研究

Analytical studies on design method and application of multi-column out-plane buckling in open-space region of the Guangzhou New TV Tower

为解决广州新电视塔透空区群柱面外稳定性设计问题,在底部透空区5柱模型试验研究的基础上,对5柱模型和各透空区外筒群柱的稳定性能进行了深入的理论研究。首先,运用有限元方法对5柱模型在各种轴力分布模式下的弹性屈曲性能以及轴压稳定承载力进行了研究,其结果显示:周边柱轴压力水平越低,5柱模型中最不利柱受到的约束越强,轴压稳定承载力也越高,而且其对初始缺陷不敏感。其次,指出计算长度系数法适用于透空区群柱面外稳定性设计,针对透空区群柱所受约束作用十分复杂的特点,提出可通过有限元屈曲分析确定柱面外计算长度系数。第三,针对5柱模型,比较了分别由试验、有限元方法和基于有限元屈曲分析的计算长度系数法确定的最不利柱轴压稳定承载力,表明有限元分析结果具有较高的准确性,同时验证了计算长度系数法用于群柱面外稳定性设计具有一定的安全性。最后,通过对有限元屈曲分析给出了各透空区外筒群柱面外计算长度系数的建议值,为了广州新电视塔透空区外筒群柱的面外稳定性设计提供了重要依据。

The instability behavior of multi-column out-plane buckling in open-space region of the Guangzhou New TV Tower is studied analytically in this paper. The elastic buckling behavior and stability capacity of most disadvantageous column in the test model （a 5-column model） is studied using finite element method, in which the change of the axial force distribution ratios of columns is considered. The results show that the stability capacity of most disadvantageous column in test model increases as axial compression force of other columns decrease. It is pointed out that effective length method can be used as a design method for verifying out-plane stability of the multi-column in open-space region of the structure where large open space is designed. In order to obtain effective length factors, an elastic buckling analysis is carried out using ANSYS, then used in predicting the buckling load according to Euler＇s formula. The comparative studies indicates that the finite element method for the stability analysis is sufficiently accurate, and the effective length method is feasible for the design of out-plane buckling of multi-column. Finally, simplified effective length values proposed for the columns in open-space region of the Guangzhou TV Tower are given as the design reference.