On the response of cold-formed steel sections under compression

This paper summarises the results of an experimental and numerical investigation performed on six series of thin-walled C-sections with intermediate and edge stiffeners. The attention focused on the response under compression and on the influence of geometrical imperfections, which significantly affect the buckling response of the member. First, compression tests allowed for determining loads and modes of failure. The influence on the collapse load of the various parameters as the material properties, the thickness, the height of the cross section and the length of the element was appraised. A comparison between the collapse deformed shape and the pattern of geometric imperfections is performed, in order to correlate the geometrical imperfections to the failure modes. The main results of FE numerical analyses performed with the software Abaqus, incorporating geometric and material nonlinearities, are also reported. The appropriateness of the specifications of the Eurocodes for modelling the geometric imperfections is finally appraised.