中国国际丝路中心大厦超高层结构巨柱计算长度影响因素研究

Research on calculation length influencing factors of mega columns of super high-rise structure of China International Silk Road Center Building

超高层中巨柱的计算长度取值对整体结构安全性和经济性有很大影响。梳理总结了现有超高层项目框架柱计算长度求解的常规方法,并以结构高度482.5m的中国国际丝路中心大厦项目为例,研究了结构自重对屈曲分析初始几何刚度的影响,对比了单点加载与不同方式多点加载对屈曲临界荷载计算结果的差异,计算了不同楼板刚度折减系数下的分区巨柱的屈曲临界荷载,分析了不同楼板刚度取值对巨柱计算长度的影响程度。通过对比带弹塑性楼板的整体模型与考虑不同楼板刚度折减系数的弹性楼板整体模型在罕遇地震下的内力分布结果,得到了巨柱屈曲分析时考虑楼板塑性变形后的刚度折减系数建议取值。最后提出了一种改进计算方法,即通过在整体计算模型上考虑结构整体自重对几何刚度的影响,基于多点对称的荷载施加方式并合理考虑楼板刚度的折减计算得到巨柱的线弹性屈曲分析结果,进而由欧拉公式反推出巨型柱的计算长度。

The calculation length of mega columns in super high-rise buildings has a great influence on the safety and economy of the overall structure.The existing conventional methods for calculation length of frame columns in super highrise projects were summarized.Taking the China International Silk Road Center Building project with the structural height of 482.5m as an example,the influence of the structural self-weight on the initial geometric stiffness of the buckling analysis was studied.The difference between point loading and multi-point loading in different ways on the buckling critical load calculation results was compared,and the buckling critical load of the mega columns in different regions under different floor stiffness reduction coefficients was calculated,and the influence of different floor stiffness values on the calculation length of the mega-columns were analyzed.By comparing the internal force distribution results of the integral model with elastic-plastic floor and the elastic floor integral model considering different floor stiffness reduction coefficients under rare earthquakes,the suggested value of the stiffness reduction coefficient considering the plastic deformation of the floor in the buckling analysis of the mega column was obtained.Finally,an improved calculation method was proposed.The influence of the whole body weight of the structure on the geometric stiffness was considered in the overall calculation model,and the linear elastic buckling analysis results of the mega column were obtained based on the symmetric multi-point loading method and reasonable consideration of the reduction of the floor stiffness.Then the calculation length of the mega column was derived from the Euler formula.