Structural stability tests on two-span channel members in bending, axial compression and torsion

The use of slender steel members promotes the competitiveness of steel structures in structural engineering. However, these members often necessitate stability verifications. Global research activities in this field have so far mainly focussed on single-span members with doubly symmetric cross-sections. For mono-symmetric sections such as channels, only a few design models exist based on experimental evidence. Moreover, the potential of structural systems such as multi-span members is yet not entirely exploited in the normative verification models. Therefore, this paper presents a comprehensive experimental study on the stability behaviour of two-span members with steel channels under combined loading. Five-point bending tests were conducted to determine the load-bearing capacities and to experimentally analyse the influence of the constructional detail of the central support, the axial load, the slenderness ratio and other parameters on the load-bearing behaviour. The article provides the scientific basis for extending the scope of the stability verification for members subjected to bending, axial compression and torsion in Annex C.2 of the novel EN 1993-1-1:2022 to two-span channel members.