Buckling lengths of unbraced multi-storey frame columns

OZMEN G., Girgin K.

STRUCTURAL ENGINEERING AND MECHANICS, vol.19, no.1, pp.55-71, 2005 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 19 Issue: 1
  • Publication Date: 2005
  • Doi Number: 10.12989/sem.2005.19.1.055
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.55-71
  • Keywords: buckling load, buckling length, effective length, sway mode, unbraced frames, isolated subassembly, multi-storey frames, design codes, 2ND-ORDER ANALYSIS, STABILITY
  • Istanbul Technical University Affiliated: Yes


In several design codes and specifications, simplified formulae and diagrams are given for determining the buckling lengths of frame columns. It is shown that these formulae may yield rather erroneous results in certain cases. This is due to the fact that, the code formulae utilise only local stiffness distributions. In this paper, a simplified procedure for determining approximate values for the buckling loads of multi-storey frames is developed. The procedure utilises lateral load analysis of frames and yields errors in the order of 10%, which may be considered suitable for design purposes. The proposed procedure is applied to several numerical examples and it is shown that all the errors are in the acceptable range and on the safe side.