Enhancing Flexural Capacity of Cold-Formed Steel Beams with an Innovative Delta-Channel Section: Experiments and Validated FE Modeling

Abstract

Cold-formed steel (CFS) lipped channels are widely used in lightweight construction, yet their open, thin-walled geometry makes them highly vulnerable to torsion-driven instability and premature buckling under bending. To address this limitation, this study introduces an innovative riveted Delta-Channel concept that partially “closes” the section, shortens free edges where buckling initiates, and increases torsional rigidity. Full-scale four-point bending tests were performed on nine specimens (three Delta sections and six lipped channels), supported by nonlinear finite element (FE) models developed in ABAQUS. Across comparable geometries, Delta sections delivered a 66–140% increase in peak load capacity and markedly improved deflection control. The developed FE models showed good agreement with the experimental results and successfully reproduced the observed flexural behaviour of the investigated sections. Despite a modest increase in material usage, the proposed Delta sections achieved substantially higher flexural capacities than comparable conventional lipped channel sections.