Comparison of Buckling Resistance of I-shaped cross-sections

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The buckling resistance of rolled I-sections, HEA and IPE, is determined by calculations in IDEA StatiCa Member, ABAQUS and by hand calculations. A verification and guide for equivalent geometric imperfections is prepared.

The study describes the choice of numerical model, results of linear buckling analysis and geometrically and materially nonlinear analysis with imperfections by two software packages and compares the buckling resistance to Winter curves in Eurocodes. Selected investigated cross-sections are HEA 300, HEA 800, IPE 300, and IPE 500 loaded by a compressive force, bending moment, or a combination of both. 


  • Recommendation for a choice of imperfection amplitudes for local buckling, global buckling, and a combined local and global buckling is provided.
  • Safety and ease of use are preferred and a flowchart is given.


  • Linear buckling analysis: IDEA StatiCa Member provides very similar results to Abaqus with a difference below 3%. 
  • Geometrically and materially nonlinear analysis with imperfections: IDEA StatiCa Member provides very similar results to Abaqus with a difference below 3%.
  • This level of deviation is common and well within the range of acceptability.
  • In terms of local buckling, the imperfection amplitude of d/200 showed a good agreement with the EN 1993-1-5 “Winter curve” for plate buckling.
  • Length proportional approach according to EN 1993-1-1 is sufficient and safe-sided when using the elastic design approach for the evaluation of imperfection amplitudes.
  • A safe-sided recommendation was formulated, introducing limit values to provide decision support, whether an interaction of local and global imperfections is required or not. 

The full report is attached.

Author: Andreas Müller M.Sc.

Responsible investigator: Prof. Dr. techn. Andreas Taras

ETH Zurich, Institute of Structural Engineering (IBK)

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