Finite-element modelling of concrete-filled steel tube columns wrapped with CFRP

Experimental evaluation of the structural behaviour of concrete-filled tubular (CFT) circular steel columns under the combined effects of axial and cyclic lateral loads is costly and challenging. This study provides a non-linear finite-element analysis (FEA) of 21 models of CFT circular steel columns wrapped with several carbon-fibre-reinforced polymer (CFRP) composite layers at the end region, which represents the critical location in terms of lateral load capacity. The intent is to confine the column end to avoid outward local buckling of the column and thus develop high strength, larger net drift and more energy dissipation. The non-linear FEA models were properly calibrated and validated with reputable experimental results; a parametric study was then conducted to assess the influence of the number of CFRP layers and axial load level on CFT circular steel column performance. Also, it was found that the column axial load level significantly affects the CFT circular steel column behaviour under lateral loading, behaviour improved as the axial load level increased. It takes a parametric investigation, in terms of strengthening system, and the findings of this study provide a useful guideline and methodology for similar strengthening of CFT steel columns.