复合荷载作用钢梁弯扭屈曲的等效弯矩系数  

Equivalent uniform moment factor for critical moment of steel beams under combined loading

作　　者：刘占科[1,2] 曹舒 文天星 周绪红[3] LIU Zhanke;CAO Shu;WEN Tianxing;ZHOU Xuhong(Key Laboratory of Mechanics on Disaster and Environment in Western China of the Ministry of Education of China,Lanzhou University,Ixinzhou 730000,China;College of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China;School of Civil Engineering,Chongqing University,Chongqing 400044,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,甘肃兰州730000 [2]兰州大学土木工程与力学学院,甘肃兰州730000 [3]重庆大学土木工程学院,重庆400044

出　　处：《建筑结构学报》2019年第4期170-179,共10页Journal of Building Structures

基　　金：国家自然科学基金项目(51308272);兰州大学中央高校基本科研业务费专项资金项目(lzujbky-2016-109)

摘　　要：为提高等效弯矩系数实用算式的计算精度和拓展等效弯矩系数实用算式的应用范围,总结了复合荷载作用下钢梁弯扭屈曲临界弯矩研究现状和特点,在临界弯矩理论背景下,等效弯矩系数取值是影响临界弯矩计算精度的主要因素。基于钢梁弯扭屈曲等效弯矩系数的计算理论,通过选取合理的单一荷载作用下临界弯矩中系数C1的数值或表达式,提出了4种常见工况的等效弯矩系数C_b的实用算式及其使用范围。在端弯矩比例为-1≤ψ≤1的范围内,对比了文中C_b实用算式与现有文献中的"4M"C_b算式,验证了文中C_b实用算式的正确性并提出了C_b算式的选用准则。通过数值算例验证了C_b算式选用准则的正确性。研究表明,当-1≤ψ≤1时C_b算式在其适用范围内都具有较高的精度,基于C_b算式及其选用准则可得到精确的临界弯矩。In order to improve the accuracy and the scope of application for the practical equations of equivalent uniform moment factor,the historical development of research on the critical moment of steel beams subjected to combined loading was reviewed and summarized.Under the background of general theory of the critical moment,the value of the equivalent uniform moment factor is the main factor affecting the accuracy of the critical moment.Four closed-form formulae were proposed for determining the equivalent uniform moment factor on the basis of its theoretical expression,by employing more accurate C1.The proposed Cb formulae were compared with current"quarter-point"equations of equivalent uniform moment factor for-1≤ψ≤1.The accuracy of the proposed formulae was checked and the selection criterion for the Cb formulae was proposed.The criterion on Cb formulae was validated by numerical examples.The results show that the proposed formulae of Cbare accurate within their scopes of applications when the end moment ratio satisfies-1≤ψ≤1.Accurate critical moments of steel beams with flexural-torsional buckling can be obtained on the basis of the proposed Cb formulae and the criterion on the Cb formulae.

关 键 词：钢梁 复合荷载 临界弯矩 等效弯矩系数 

分 类 号：TU392.1[建筑科学—结构工程]