07.20: Application of the compound strip method in buckling analysis of cold‐formed steel built‐up sections

Abstract

In this paper, the compound strip method is utilised and extended for the stability analysis of cold-formed steel built-up sections. The discrete fasteners are incorporated in the analysis such that they can be placed anywhere within the length of the member. A beam element with geometrical and material properties of the fastener is adopted to model the connection between the individual sections. The stiffness matrix terms for the connection element are derived and added directly to the global stiffness matrix of the considered built-up sections. The proposed numerical technique is verified through various examples and the results are compared with the finite element solutions. The results obtained demonstrate that the developed technique can accurately and efficiently model the behaviour of cold-formed steel built-up sections. Furthermore, the influence of the fasteners properties, their longitudinal spacing and also the boundary conditions on the overall buckling behaviour of built-up sections is examined through numerical examples. The simplicity of the proposed technique facilitates an extensive parametric study of cold-formed built-up sections including the search for optimal placement of fasteners and combinations of component sections in built-up profiles.

State-of-the-Art: Integrating Fastener Technology and Design Guidelines for Enhanced Performance of Cold-Formed Steel Sections

“…The findings of the study indicate that the use of discrete fasteners may effectively improve the overall built-up open-section columns' buckling capacity, irrespective of the existence of web stiffeners [84]. In the compound strip method (CSM) stability investigation of CFS built-up columns, it came to our attention that the specific configurations of screws had minimal influence on the moment capacities of constructed open-section beams.…”

Investigating the Factors Influencing the Strength of Cold-Formed Steel (CFS) Sections

“…Furthermore, the presence of discrete connectors in built-up sections has an effect on the overall buckling behavior and causes a change in the mode of buckling [83]. It is notable that it is possible to improve the composite action of CFS-QBC with longitudinal stiffeners by increasing the number of connection rows and by decreasing the screw spacing.…”