Behaviour, finite element modelling and design of cruciform section steel columns

A study into the mechanical behaviour and design of steel equal-leg cruciform section members subjected to axial compression is presented. Experimental data from the literature are used to validate shell finite element models developed within the commercial package ABAQUS for their load-deformation and ultimate behaviour. A numerical parametric study then considers cruciform section columns with a wide range of slenderness ratios and various common boundary conditions. The mechanical response and load-carrying capacity are shown to be dependent not only on the column slenderness but also on the torsional to flexural elastic buckling load ratio. Finally, a recently established design approach for steel angle section columns is extended to include cruciform section members, and verified against the available results. It is found through reliability analysis based on the EN 1990 procedure that the new proposal also offers substantially improved accuracy and consistency in strength predictions compared to the existing codified design rules for cruciform section columns; a recommended partial safety factor of 1.0 is determined.