高层建筑跃层柱稳定分析与讨论

Analysis and discussion on stability of skip-floor column in high-rise building

针对高层建筑跃层柱稳定分析中经常出现计算长度系数过小的问题,讨论了稳定分析中欧拉公式的应用范围,整理了常见柱子的临界长细比和高宽比,建议稳定分析前进行稳定与强度控制判断。针对屈曲分析方法的合理应用问题,总结了常用的整体屈曲分析方法与局部加载分析方法各自的特点及适用范围,并提出了基于局部加载分析结果的反推算法,最后结合案例进行分析和探讨。研究结果表明:跃层柱计算长度系数过小的问题很可能是由于模型设置、稳定临界荷载计算等方面原因;验证欧拉公式的适用范围本质上是验证跃层柱是稳定控制还是强度控制;由屈曲分析获得临界荷载并反算的计算长度系数有可能是虚假值,应同时验证其对应的临界应力。反推算法结合了整体屈曲分析方法和局部加载屈曲分析方法各自的优点,可提高整体屈曲分析中寻找屈曲模态的效率。

In view of the calculated effective length factors are usually too small in the stability analysis of skip-floor column in high-rise building,the application scope of the Euler’s formula was discussed,and the critical slenderness ratio and height-width ratio of common columns were presented.The advice that the stability control or the strength control should be judged before stability analysis was proposed.In order to promote the reasonable application of the buckling analysis methods for skip-floor column,the respective characteristics and application scope of the common analysis methods,such as global buckling analysis method and the local loading analysis method were summarized,and the inversion method based on the local load analysis results was proposed.Finally,the above presented methods were analyzed and discussed by cases.The results show that the effective length factor too small is probably due to the unreasonable setting for the finite element model and the unreasonable calculation of bucking critical load.It is essentially to verify whether skip-floor column is the stability control or the strength control for verify the application scope of the Euler’s formula.The calculated effective length factor of skip-floor column by inverse computation from critical load may be false value,the corresponding critical stress should be verified simultaneously.The reverse calculation method have the advantages of the global buckling analysis method and the local loading analysis method,it can greatly improve the efficiency of finding buckling modes in the global buckling analysis.