(1 西安建筑科技大学土木工程学院， 西安 710055；2 结构工程与抗震教育部重点实验室(西安建筑科技大学)， 西安 710055)

［摘要］与有效宽度法和有效屈服强度法相比，直接强度法更简单。采用ANSYS有限元软件建立模型分析了名义屈服强度fy为690MPa高强钢薄壁方形截面轴压构件的极限承载力，并和直接强度法、修正的直接强度法相比较。主要参数：板件宽厚比b/t=23，30，40，50和60；构件长细比λ=20，30，40，50，60，70，80和90。研究结果表明：对fy=690MPa的薄壁方形截面（b/t>20）轴压构件，采用直接强度法和修正直接强度法计算时，其稳定系数采用《钢结构设计标准》（GB 50017—2017）中的a类曲线；对长细比70≤λ≤90的构件，3种方法均偏保守；对长细比20≤λ<70的构件，在大部分宽厚比范围内，Kwon等提出的修正直接强度法能较好地预测有限元计算结果，直接强度法偏于不安全，Shen Hongxia提出的修正直接强度法偏安全。 

［关键词］高强钢；薄壁方形截面；轴压构件；局部-整体相关屈曲；极限承载力；直接强度法；修正的直接强度法 

中图分类号：TU391，TU323-1，TU311-2 文献标识码：A文章编号：1002-848X(2021)18-0047-06

Study on direct strength method for the ultimate carrying capacity of 690MPa high-strength steel thin-walled square box section centric compression member

SHEN  Hongxia1,2,  WANG  Chao1,2 

(1 School of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an 710055， China；2 Key Lab of Structural Engineering and Earthquake Resistance, Ministry of Education (Xi’an University of Architecture and Technology), Xi’an 710055， China) 

Abstract: Direct strength method (DSM) is simpler compared to effective wide method and effective yield strength method. The ultimate carrying capacities of thin-walled square box section centric compression members made from high-strength steel with a nominal yield stress of 690MPa were analyzed by ANSYS finite element program and compared with the DSM and modified DSM. The plate width-to-thickness ratio(b/t) was taken as 23, 30, 40, 50 and 60 and the member slenderness ratio(λ) as 20, 30, 40, 50, 60, 70, 80 and 90. The study shows that curve a provided in  Standard for design of steel structures（GB 50017—2017）should be employed for thin-walled square box section (b/t>20) centric compression members with fy=690MPa when using the DSM and modified DSM, that the DSM and modified DSM proposed by Kwon etc. and Shen Hongxia are conservative for members with 70≤λ≤90, that the modified DSM proposed by Kwon etc. can accurately predict the finite element results and the DSM is unsafe and the modified DSM proposed by Shen Hongxia is safe over a wide range of wide-to-thickness ratios for columns with 20≤λ<70.  

Keywords:high-strength steel； thin-walled square box section； centric compression member； local-overall interaction buckling； ultimate carrying capacity； direct strength method； modified direct strength method

*国家自然科学基金项目(51978563)。

 作者简介：申红侠，博士，副教授，硕士生导师，Email: shenhongxia88@126.com。