Improving the GBT-based buckling analysis of restrained cold-formed steel members by considering constrained deformation modes

• Published in: Thin-walled structures Vol. 165; p. 107928
• Main Authors: Araujo, Heitor F., Basaglia, Cilmar, Camotim, Dinar, da Silva, Thiago G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-08-2021
• Subjects: Braced/restrained cold-formed steel members; Buckling analysis; Generalised Beam Theory (GBT); Purlin-sheeting systems; Semi-analytical buckling formulae; Sheathed wall stud systems; Sheathed wall stud systems; Purlin-sheeting systems; Buckling analysis; Generalised Beam Theory (GBT); Braced/restrained cold-formed steel members; Semi-analytical buckling formulae
• ISSN: 0263-8231; 1879-3223
• DOI: 10.1016/j.tws.2021.107928

This paper reports the development, numerical implementation and practical application of a novel/improved approach to perform the buckling analysis of braced/restrained cold-formed steel members by means of Generalised Beam Theory (GBT). The novelty consists of a cross-section analysis procedure that incorporates elastic restraints and, therefore, leads to a set of constrained deformation modes with clear structural meaning for the member under consideration. The potential of the developed GBT-based approach is illustrated by presenting and discussing numerical results concerning cold-formed steel (i) purlins restrained by sheeting and (ii) studs braced by sheathing. For validation and assessment purposes, several GBT-based results are compared with values provided by the programs GBTul2.0 (conventional GBT), CUFSM (finite strip method) and/or Ansys (shell finite elements). It is shown that the proposed GBT-based approach is much more efficient than the conventional one, as it offers the possibility of obtaining accurate buckling results with very few (constrained) deformation modes – this feature makes it possible to derive semi-analytical formulae to calculate critical buckling loadings of braced/restrained members. This capability is used in this work to derive GBT-based semi-analytical formulae providing critical length and buckling loading estimates for cold-formed steel purlins and studs restrained by panels (sheeting or sheathing).
•Novel approach for the buckling analysis of restrained members based on Generalised Beam Theory (GBT).•Restraints included in the GBT cross-section analysis, leading to constrained deformation modes.•Constrained deformation modes lead to improved structural interpretation and computational efficiency.•Application to the buckling analysis of purlins restrained by sheeting and studs braced by sheathing.•Semi-analytical formulae derived to estimate purlin lateral–distortional and stud distortional buckling loadings.