高强钢焊接箱形截面双向压弯构件屈曲后强度设计方法研究

Research on the Design Methods for the Post-Buckling Strength of High-Strength Steel Welded Box Beam-Columns Under Biaxial Bending

相比于《钢结构设计规范》(GB 50017—2003),《钢结构设计标准》(GB 50017—2017)取得了较大的进步,允许板件先于构件发生屈曲,并利用了板件屈曲后强度。GB 50017—2017对轴心受压构件、受弯构件和单向压弯构件均给出了屈曲后强度计算公式,但对双向压弯构件却未给出计算公式。分析了已有的高强钢压弯构件屈曲后强度计算方法,基于GB 50017—2017中的压弯构件稳定承载力计算公式,提出了双向压弯构件屈曲后强度计算公式,收集已有高强钢焊接箱形截面压弯构件屈曲后强度的试验和有限元结果以验证公式的有效性。研究结果表明,提出的计算公式能在大部分构件长细比和板件宽厚比范围内偏于保守地预测名义屈服强度为460 MPa和690 MPa的高强钢焊接箱形截面双向压弯构件的屈曲后强度。

Compared to the Code for Design of Steel Structures(GB 50017—2003),a great progress has been made,in Standard for Design of Steel Structures(GB 50017—2017),due to the fact that the local buckling of plates is allowed to occur prior to the overall buckling of a member and the post-buckling strength is considered.In GB 50017—2017,the formulae for the post-buckling strength of columns,beams,and beam-columns under uniaxial bending are provided,but the formulae of beam-columns under biaxial bending are not given.This paper analyzes the existing calculation methods for the post-buckling strength of high-strength steel beam-columns and presents the formulae for the post-buckling strength of beam-columns under biaxial bending based on the existing formulae in the GB 50017—2017 for the stability capacity of beam-columns,and the accuracy of provided formulae is verified based on existing experimental and numerical results of the post-buckling strength of high-strength steel welded box section beamcolumns.The results show that the provided formulae can conservatively predict the post-buckling strength of 460 MPa and 690 MPa steel welded box beam-columns under biaxial bending over a wide range of slenderness ratios and width-to-thickness ratios.