Static Bearing Capacity Analysis of CFRP-Reinforced Short CHS Steel Tubular Columns under Axial Compression

To predict the ultimate strength of a short circular hollow section (CHS) steel tubular columns reinforced with carbon fibre-reinforced polymer (CFRP), both theoretical and numerical analyses were carried out. In the theoretical analysis, based on equivalent section method, the equations for calculating the load bearing capacities of CHS steel tubular columns under axial compression are deduced, which correspond to two different reinforcing methods, in which CFRPs are arranged in circumferential placement and in longitudinal-circumferential placement. In the numerical analysis, both eigenvalue buckling method and Riks method are combined to build a nonlinear finite element model of the tubular columns under axial compression. The finite element analysis for the stress distribution of the longitudinal and circumferential CFRPs shows that the circumferential CFRPs are under tension and restrain the radial deformation of the tubular columns, while the longitudinal CFRPs share the axial compression and restrain the deformation of the tubular columns. The comparison of the numerical results, theoretical results and reported experimental results show that the maximum deviation among them is no more than 2%, which verifies the finite element model and deduced equations.