Numerical investigations on elastic buckling and hysteretic behavior of steel angles assembled buckling-restrained braces. (May 2018)

• Record Type: Journal Article
• Authors: Tong, Jing-Zhong; Guo, Yan-Lin
• Is Part Of: Journal of constructional steel research. Volume 144(2018)
• Page Start: 21
• Page End: 39
• Publication Date: 2018-05
• Subjects: Steel angles assembled -- Buckling-restrained braces -- Elastic buckling behavior -- Hysteretic behavior -- Finite element analysis -- Restraining ratio; Steel, Structural -- Periodicals; Building, Iron and steel -- Periodicals; Acier de construction -- Périodiques; Construction métallique -- Périodiques; 624.1821
• DOI: 10.1016/j.jcsr.2018.01.015
• Languages: English
• ISSNs: 0143-974X

Abstract

Abstract: This paper presents a numerical investigation on elastic buckling and hysteretic behavior of a steel angles assembled buckling-restrained brace (SAA-BRB). The SAA-BRB is composed of a cruciform-sectional steel core encased by an external restraining system, which consists of four steel angles connected together by high-strength bolts and spacers. It is found that the SAA-BRB may fail in a global buckling mode or in a local buckling mode. In order to predict the global and local buckling behavior of SAA-BRBs, two design parameters: the restraining ratio and segment restraining ratio are proposed. To determine these two design parameters, a simplified theoretical model of SAA-BRBs and an accurate finite element (FE) model are used to investigate the global and local elastic buckling behaviors of SAA-BRBs. Based on more than 500 FE results, explicit expressions of the restraining ratio and segment restraining ratio are obtained and validated to be sufficiently accurate for practical design applications. In addition, 20 refined FE models considering material and geometrical nonlinearities are used to carry out parametric studies for comprehensively investigating the hysteretic behavior of SAA-BRBs. Finally, the following design recommendations for fix-ended SAA-BRBs are proposed: (1) the restraining ratio should be >2.2 to prevent a SAA-BRB from the global buckling failure, and (2) the segment restraining ratio should be >6.0 to prevent a SAA-BRB from the local buckling failure. Highlights: SAA-BRB is presented and its restraining system consists of four angle steels assembled by bolts. Global and local failure modes of SAA-BRBs are revealed. Formulas for global and local elastic buckling loads are provided via theoretical and FE numerical analyses. Hysteretic analyses of 20 refined FE models are conducted via Abaqus. Design recommendations based on restraining ratio requirements are presented.