Numerical Study of Stiffened Cold-Formed Steel Apex Moment Connection

Abstract

Cold-Formed Steel sections are commonly used in residential and commercial buildings. The bolted moment connections can be used to connect the different structural components of these buildings together. These connections allowing the transfer of the internal forces of the structures. The main objective of this paper is to study numerically the behavior of the apex bolted moment connection for cold formed sections. The deflection and the stress distribution at critical sections for stiffened 2C (double back-to-back) CFS were investigated for three cases. Connecting single gusset plate was used in the first case, while the second cases with two connecting double gusset plates with cutting compression flange and the third case with double gusset plate with continuous compression flange. A finite element modelling was developed by using the ANSYS workbench to simulate the apex connection of cold-formed steel sections. A numerical model was developed and verified using the experimental results. The parametric study was carried out to investigate the effect of connecting gusset plate thickness, bolts patterns, and bolts pretension force on the resistance of the cold-formed steel sections. Based on this analysis the deflections, ultimate failure load, failure modes of specimens were studied and different failure modes, Moreover, moment resistance ratio and rotations for this type of connection are deduced. The study showed that the great effect of using continuous gusset plate and using the pretension load equal to 20% in the connection efficiency.