Simulation of screw connected built-up cold-formed steel back-to-back lipped channels under axial compression

A practical numerical model for thin-walled steel connections and built-up members

“…This method of modelling bolted connections between cold-formed steel members has been also adopted by other researchers [28,29], with reasonable agreement achieved between the test and FE results. A similar approach has been followed in [30], where a user-defined element was assigned a load-deflection curve determined from shear tests on screw fasteners, to model the behaviour of cold-formed steel built-up columns. However, this method is reliant on the accuracy and limited by the scope of the underpinning test data; it can also result in significant membrane deformations developing at the ends of the nonlinear springs, leading to a local underestimation of the stiffness -see Fig.…”

“…More recently, Kechidi et al [30] developed a user-defined element including load-deflection curves of a series of screw fasteners, determined from tests, to model the behaviour of coldformed steel built-up columns, while Ye et al [32][33][34][35] successfully replicated the behaviour of built-up beams and bolted connections subjected to monotonic and cyclic loading. Phan and Rasmussen [36] numerically simulated cold-formed steel built-up sections subjected to bending about their minor axis, where the connectors were modelled as nonlinear springs which were assigned force-bearing deformation relationships obtained from single shear tests on bolted joints.…”

Study on Strength and Behaviour of Cold-Formed Steel Built-up Columns

“…Investigations on back-to-back connectivity in lipped channels were carried out in [3,[33][34][35][36][37][38][39][40][41]. Thirty-two columns with screw connectivity were experimentally investigated in [33].…”

Axial strength of back-to-back cold-formed steel channels with edge-stiffened holes, un-stiffened holes and plain webs

“…The local critical elastic buckling load, Pcrl, is calculated for a CFS channel column with unstiffened holes using Equation (10) [13][14][15][16].…”

“…An experimental study was conducted by Fratamico et al. [12][13][14] to assess the composite action of back-to-back plain channels. For slender columns, it was found that the screws can increase the strength by as much as 21% for slender columns.…”