Stability of beams in steel eccentrically braced frames


Yigitsoy G., TOPKAYA C., Okazaki T.

JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, vol.96, pp.14-25, 2014 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 96
  • Publication Date: 2014
  • Doi Number: 10.1016/j.jcsr.2014.01.002
  • Journal Name: JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.14-25
  • Keywords: Eccentrically braced frame, Overstrength, Finite element, Nonlinear analysis, Steel, LINK BEAMS, BEHAVIOR
  • Middle East Technical University Affiliated: Yes

Abstract

When an eccentrically braced frame (EBF) is subjected to a severe seismic event, large axial force and bending moments are produced in the beam outside of the link Designers face significant difficulties in meeting the capacity design requirement to keep these beams elastic. On the other hand, previous research suggests that controlled yielding in the beams is not detrimental to EBF performance as long as stability of the beam is maintained. A computational study was undertaken to investigate the stability of cyclically loaded EBFs. A total of 51 EBF sub-assemblage models, none of which satisfies the capacity design requirement, were selected and investigated through three-dimensional, nonlinear finite element analysis. The results indicate that the link overstrength factor should be a function of the link length for performing capacity design of the beam outside of the link This is because flexure yielding links, which are more problematic to beam stability, tend to develop smaller overstrength compared to shear yielding links. Furthermore, designs with demand-to-capacity ratios greater than unity were found to be viable provided that the stability of the beam is maintained by making use of a slenderness limit developed herein. (C) 2014 Elsevier Ltd. All rights reserved.