Behaviour of Concrete-Filled Double Skin Tubular Short Column with Plate Stiffeners Welded Intermittently under Axial Compression

Abstract

This paper presents the experimental and finite element analyses of the behaviours of stub circular and square concrete-filled double steel tubular (CFDST) columns intermittently welded with plate stiffeners under axial compression. The plate stiffeners are welded to the inner surface of the outer tube through predrilled holes. Twenty specimens consisting of two concrete-filled steel tubular (CFST), two unstiffened CFDST, and sixteen stiffened CFDST were tested under axial compression to determine the failure patterns and obtain the load versus axial shortening curve. The key variables are the distance of weld spacing and the dimension of the plate stiffeners. Based on the experiment results, the authors have identified the possible local buckling locations, including the peak load of the specimens that were significantly affected by the intermittently welded plate stiffeners. The developed finite element model is verified by comparing the current and previous experimental results, and it provides an acceptable mean ratio of 1.01 and a standard deviation of 0.04. The validated FE model is employed in a parametric study to investigate the effects of critical parameters, including the two shapes of the specimens, dimension of the plate stiffeners, and weld spacing, on the load-carrying capacity. The findings of the parametric study can be used to justify the optimum dimensions of plate stiffeners for the best stiffened CFDST performance.