Typical processes in fabrication of cold-formed hollow sections include cold-bending and welding, and effects of these two fabrication processes, mainly residual stresses and strains, should be incorporated into numerical models in assessing structural behaviour of these sections as initial material and geometrical imperfections. A close look into various numerical investigations reported in the literature into the structural behaviour of both stocky and slender columns of cold-formed hollow sections revealed the use of various modelling techniques, depending on the levels of accuracy required and efforts provided.
A comprehensive experimental programme on stocky and slender columns of S690 cold-formed hollow sections is carried out at CNERC. Residual stresses, cross-sectional resistances and overall buckling behaviour of those columns have been investigated. Moreover, an integrated and coordinated advanced numerical simulation (iCANS) approach is proposed to assess effects of transverse bending and longitudinal welding into the structural behaviour of these S690 sections under different boundary and loading conditions. The proposed models have been successfully calibrated against measured temperature, residual stresses and load-deformation characteristics of both stocky and slender columns of these S690 sections.
The proposed iCANS approach is able to accurately predict the structural behaviour of these S690 sections under effects of various fabrication processes directly, and hence, improved structural efficiency of these sections is readily achieved without any simplification in their initial material imperfections.