Behaviour of cold-formed steel built-up closed columns composed by angle profiles

Abstract

This paper presents the experimental investigation of cold-formed built-up closed sections with intermediate web stiffeners under axial compression with hinged end conditions. The specimens were formed using two angle sections with edge and intermediate stiffeners, connected by self-tapping screws. Three series of tests were conducted by varying the width of the intermediate web element. Twelve columns were tested by varying the column length. The specimens were failed by local, flexural, and interaction of these buckling modes. Non-linear Finite-element Analysis (FEA) was carried out using ANSYS. FEA results were compared with the experimental results. It is observed that FEA results closely resemble to experimental results. An extensive parametric study was carried out using validated finite-element model by varying the cross-sectional geometries of cold-formed built-up closed section with intermediate stiffeners. The column strengths predicted from the FEA was compared with the design strengths calculated using the AISI specification of cold-formed steel structures. The reliability of the current design method was assessed by reliability analysis.