Local and post-local buckling of concrete filled steel welded box columns

Abstract

This paper considers the local and post-local buckling of steel plates in thin-walled concrete filled steel box columns. Concrete filled steel fabricated box columns and the many advantages that accrue from their use are reviewed. The concept of local buckling is described and the effects it has on the strength of concrete filled steel columns is discussed. An extensive set of experiments for the local and post local buckling behaviour of concrete filled steel box columns is presented. A semi-analytical finite strip method developed elsewhere which includes the beneficial effect of concrete is augmented to incorporate the true stress-strain behaviour and the residual compressive and tensile stresses produced by welding. The model is then calibrated with the experiments of this paper. Slenderness limits derived from this analysis are compared with existing Australian and British standards and these illustrate the advantages obtained from a rational local buckling analysis. A post-local buckling model based on the effective width principle is then established which can be used to determine the strength of a concrete filled box section.