Experimental and numerical investigations of CFRP strengthened short SHS steel columns

This paper presents the details of experimental and numerical investigations on the behaviour and axial compression capacity of Carbon Fibre Reinforced Polymer (CFRP) strengthened cold-formed, short Square Hollow Section (SHS) steel columns. Initially, an experimental investigation consisting of seven test columns was conducted to investigate the influence of CFRP strengthening layout on the axial compression capacity of short SHS steel columns. In addition, the effect of CFRP wrapping end condition was also investigated. Experimental results showed that CFRPs are very effective in strengthening short SHS columns, where axial compression capacity enhancements up to 2.6 times were observed. Then a numerical simulation was implemented using ABAQUS by which CFRP and adhesive were modelled using continuum and cohesive elements deploying Hashin and cohesive law criteria. The finite element models were validated using experimental results and then used in a detailed parametric study. Using the finite element analysis results suitable improvements were proposed to the existing design equations available in the literature. Finally, a new set of design equations based on Direct Strength Method (DSM) is proposed in this paper to determine the axial compression capacity of CFRP strengthened SHS columns subjected to local buckling.