Interactive Buckling Analysis of Thin-Walled Cold-Formed Steel Members via Critical Load Erosion Theory

  • D. Dubina
Conference paper
Part of the CISM International Centre for Mechanical Sciences book series (CISM, volume 379)


The European buckling curves actually enclosed in EUROCODE 3 — Part 1.3, used for the stability analysis of cold-formed steel members, have resulted by means of statistical processing of the experimental data carried out on hot-rolled steel profiles.

Due to the nature of imperfections of thin-walled in cold-formed steel profiles, which are different from that of hot-rolled ones, and taking into account to the interaction between the overall and local buckling, the present European buckling curves cannot appropriately describe the behaviour of cold-formed members.

In this case, both the imperfections and wall slenderness influence the buckling of the member in compression and/or bending.

Starting from the Ayrton-Perry formula of European buckling curves, and based on the Erosion of Critical Bifurcation Load — ECBL — theory, a new approach for the interactive buckling of cold-formed steel members is proposed. In fact, the general format of European buckling curves is still valid, and only the α imperfection coefficient must be calibrated in terms of both the erosion factor and effective area of the member cross-section. The erosion of critical load is evaluated by statistical processing of some selected series of cold-formed steel specimens. The DATACOST experimental database was built to be used in this reason.

A large number of numerical and experimental comparative results demonstrate the validity of the proposed approach.


Local Buckling Torsional Buckling Compression Member Erosion Coefficient Distortional Buckling 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



gross cross-section area


effective cross-section area

C1, C2, C3

factors depending on the loading and end restraint conditions


bending coefficient


coefficient for unequal end moment


coefficient for moment causing compression on the shear centre side of the centroid


Young Modulus


yield stress


shear modulus


second moment of area of the cross-section about the y-axis


second moment of area about the minor axis


St. Venant torsion constant of the cross-section


warping constant of the cross-section

k, kw

effective length factors for bending about z-axis and for twisting


is the length of the beam between points which have lateral restraint

lz, lx

effective lengths for bending about the z-axis and for twisting

Lz, Lt

unbraced lengths of compression member for bending about the z-axis and for twisting


member effective length in flexural buckling about y-y axis


member effective length in torsional buckling


bending moment resistance of the section


the elastic critical moment for lateral torsional buckling for the gross cross-section


the experimental failure moment


the full plastic resistance of the beam


axial load


Euler critical buckling load


experimental failure load


full plastic resistance of the column


effective cross-section plastical strength


compressive force due to design load


design buckling resistance


critical flexural-torsional load


critical torsional load


flexural torsional load with respect to the major inertia axis, y-y


reducing factor of area in interactive local-overall buckling


the reducing factor of section modulus in interactive local-lateral torsional buckling


polar radius of gyration of the cross-section about the shear centre

ry, rz

radius of gyration of the cross-section about the y- and z-axes, respectively


section modulus of the effective cross-section when subject only to moment about relevant axis


the full plastic section modulus of the cross-section


distance from the shear centre to the centroid along the principal y-axis, taken as negative


the coordinate of the point of load application


z coordinate of the shear centre


reduction factor for the buckling of compression members


reduction factor for the buckling of bending members


imperfection coefficient for compression members


imperfection coefficient for bending members


mono-symmetry section constant about the y-axis


partial safety factor


member slenderness for the relevant buckling mode

\(\bar \lambda \)

relative member slenderness for compression members

\(\bar \lambda \)LT

relative member slenderness for bending members


generalised imperfection factor for compression members


generalised imperfection factor for bending members


erosion factor for compression members


erosion factor for bending members


elastic buckling stress in an axially loaded compression member for flexural buckling about the z axis


elastic buckling stress in an axially loaded compression member for torsional buckling


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Copyright information

© Springer-Verlag Wien 1998

Authors and Affiliations

  • D. Dubina
    • 1
  1. 1.Technical University of TimisoaraTimisoaraRomania

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