单轴对称截面轴压构件弯扭失稳换算长细比的一般计算式  

General Formula of Equivalent Slenderness Ratio for Axial Compression Members with Monosymmetrical Cross-Section Under Flexural-Torsional Buckling

作　　者：刘占科[1,2] 徐应鲜 周绪红[3] 常洲旗 马张永 LIU Zhanke;XU Yingxian;ZHOU Xuhong;CHANG Zhouqi;MA Zhangyong(Key Laboratory of Mechanics on Disaster and Environment in Western China,the Ministry of Education of China,Lanzhou University,Lanzhou 730000,China;College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China;School of Civil Engineering,Chongqing University,Chongqing 400044,China;Gansu Science and Technology Construction Group Co.,Ltd.,Lanzhou 730300,China)

机构地区：[1]兰州大学西部灾害与环境力学教育部重点实验室,兰州730000 [2]兰州大学土木工程与力学学院,兰州730000 [3]重庆大学土木工程学院,重庆400044 [4]甘肃省科工建设集团有限公司,兰州730300

出　　处：《建筑钢结构进展》2024年第11期36-46,共11页Progress in Steel Building Structures

基　　金：国家自然科学基金(52278184);兰州大学中央高校基本科研业务费专项资金资助项目(lzujbky-2021-kb03)。

摘　　要：单轴对称截面轴压构件弯扭失稳的换算长细比是计算其极限荷载的重要参数。基于单轴对称截面轴压构件弯扭失稳的平衡微分方程,采用Galerkin法推导了4种边界约束条件弯扭失稳临界荷载的一元二次方程,并进一步得到了基于荷载比、双长细比的弯扭失稳换算长细比理论式。基于理论式,分别对比了我国现行标准GB 50017—2017中双角钢组合T形截面轴压构件扭转失稳、弯扭失稳的换算长细比,揭示了其中存在的问题;提出了新的双角钢组合T形截面轴压构件扭转失稳、弯扭失稳换算长细比的计算式,并与理论式的计算结果进行对比。结果表明,对于不同边界约束条件的轴压构件,其弯扭失稳临界荷载或换算长细比的形式不尽相同;相较于GB 50017—2017中的公式,所建议的双角钢组合T形截面轴压构件扭转失稳、弯扭失稳的换算长细比具有更高的精度,且适用于4种边界约束条件和115个等边双角钢组合T形截面、71个长肢相并的不等边双角钢组合T形截面和71个短肢相并的不等边双角钢组合T形截面。The equivalent slenderness ratio is an important parameter for calculating the ultimate load of axial compression members with monosymmetrical cross-section under flexural-torsional buckling.Based on the equilibrium differential equation of flexural-torsional buckling of axial compression members with monosymmetrical cross-section,the quadratic equation of flexural-torsional buckling of members with four different boundary conditions were derived by Galerkin method.Furthermore,the theoretical formulae of the equivalent slenderness ratio of flexural-torsional buckling were obtained on the basis of load ratio or double slenderness ratio.Based on the theoretical formulae,the equivalent slenderness ratio of torsional buckling and flexural-torsional buckling of axial compression members with double-angle compound T-section in current Chinese standard GB 50017-2017 was compared,and the existing problems were revealed.New equivalent slenderness ratio of torsional buckling and flexural-torsional buckling of axial compression members with double-angle compound T-section were proposed.The results show that the critical buckling load and equivalent slenderness ratio of axial compression members are not quite the same for different boundary conditions.The proposed formulae of equivalent slenderness ratio are of more accuracy than the formula provided in GB 50017-2017.The proposed formula is also suitable for four kinds of boundary constraint conditions,and for 115 double equal-leg angle sections,71 double unequal-leg angle sections with short leg outstanding and 71 double unequal-leg angle section with long leg outstanding.

关 键 词：单轴对称截面轴压构件 弯扭失稳 临界荷载 换算长细比 

分 类 号：TU391[建筑科学—结构工程]