The effect of semi-rigid joints on the design of cold-formed steel portal frame structures

Abstract

This paper investigates the effect of semi-rigid joints and finite connection length on the design of cold-formed steel portal frames. The performance of frames sized using a rigid joint and full joint strength assumption is compared with frames having semi-rigid joints and partial strength. It goes on to describe whether it can offset the fact that the joints cannot sustain the full moment capacity of the sections. Experimental, analytical and finite element modelling techniques have been used. They demonstrate that frames of modest span sized using a rigid joint and full joint strength assumption, are unsafe under gravity load and do not satisfy the ultimate limit state. Designers should therefore take the semi-rigidity and partial strength of the joints into consideration when analysing cold-formed steel portal frames.