A new method for determining the effective length factor of columns in partially braced frames on elastic supports

Adel Slimani, Toufik Belaid, Messaoud Saidani, Fatiha Ammari, Redouane Adman

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
6 Downloads (Pure)


The effective buckling length factor is an important parameter in the elastic buckling analysis of steel structures. The present article aims at developing a new method that allows the determination of the buckling factor values for frames. The novelty of the method is that it considers the interaction between the bracing and the elastic supports for asymmetrical frames in particular. The approach consists in isolating a critical column within the frame and evaluating the rotational and translational stiffness of its restraints to obtain the critical buckling load. This can be achieved by introducing, through a dimensionless parameter Phi, the effects of coupling between the axial loading and bending stiffness of the columns, on the classical stability functions. Subsequently, comparative and parametric studies conducted on several frames are presented for assessing the influence of geometry, loading, bracing, and support conditions of the frame columns on the value of the effective buckling length factor K. The results show that the formulas recommended by different approaches can give rather inaccurate values of K, especially in the case of asymmetric frames. The expressions used refer solely to local stiffness distributions, and not to the overall behavior of the structure.
Original languageEnglish
Article numberSEM22088C
Pages (from-to)825-835
Number of pages11
JournalStructural Engineering and Mechanics
Issue number6
Publication statusPublished - 25 Mar 2023

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The authors are grateful to both the Faculty of Civil Engineering of the USTHB (Algeria) and the Faculty of Engineering, Environment and Computing at Coventry University (UK) for proving their research facilities for the completion of this research. The authors declare that they have no conflicting interest or known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper


  • effective length factor
  • critical load
  • elastic buckling
  • stability functions
  • instability

ASJC Scopus subject areas

  • Engineering(all)


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