弱支撑框架柱计算长度系数的实用算法  

Practical method for determining calculating length coefficient of weakly supported frame columns

作　　者：兰树伟 陈旭 周东华[2] 毛德均 LAN Shuwei;CHEN Xu;ZHOU Donghua;MAO Dejun(College of Architecture and Civil Engineering,Kunming University,Kunming 650214,China;School of Architectural Engineering,Kunming University of Science and Technology,Kunming 650504,China)

机构地区：[1]昆明学院建筑工程学院,云南昆明650214 [2]昆明理工大学建筑工程学院,云南昆明650504

出　　处：《四川建筑科学研究》2021年第5期16-25,共10页Sichuan Building Science

基　　金：云南省教育厅科学研究基金项目(2021J0703);国家自然科学基金(51868034)。

摘　　要：《钢结构设计标准》给出了强支撑无侧移框架柱和无支撑自由侧移框架柱计算长度系数的计算表格,而对于介于这两者之间的弱支撑弹性侧移的框架柱,目前规范尚缺少相应的计算公式和表格。对此,本文基于弹簧-摇摆柱模型建立了弱支撑弹性侧移框架柱的扩展结构,通过临界荷载因子实现了扩展结构的临界力与原结构的临界力之间的转换,将求解框架柱计算长度系数的复杂二阶问题转化为计算压杆抗侧刚度的简单一阶问题,获得了一种确定弱支撑受压柱计算长度系数的实用算法,并提供了相应的计算表格。本文还推导了可按照无侧移框架柱计算稳定性的侧移临界刚度,此刚度可作为计算框架柱二阶效应时选择按照P-Δ效应还是P-δ效应的判别标准。最后,选取了2个算例进行计算验证,计算结果表明:该方法具有很好的精度及准确性,可供工程设计使用。Standard for design of steel structures gives calculation tables for calculating the calculated length factor of the non-sideways frame column and the free sideways frame column,for the frame column of the weak support elastic lateral displacement between the two,the current specification lacks the corresponding calculation formula and table.Based on the spring-swinging column model,an extended structure of weakly supported elastic side-shift frame columns is established.The critical load factor is used to realize the conversion between the critical force of the extended structure and the critical force of the original structure.The complex second-order problem of coefficients is transformed into a simple first-order problem of calculating the lateral stiffness of compression rods.The practical method for determining the calculation length coefficient of weakly supported compression columns is obtained and corresponding calculation tables are provided.This paper also deduces the lateral migration critical stiffness that can be calculated according to the column without the lateral displacement frame,which can be used as a criterion for calculating the second-order effect of the compressed column according to P-Δeffect and P-δeffect.Finally,two examples are selected for calculation and verification,whose calculation results show that the method has good accuracy,which can be used in engineering design.

关 键 词：框架柱 抗侧刚度 临界荷载因子 侧移临界刚度 计算长度系数 

分 类 号：TU391[建筑科学—结构工程] TU398.2