Experimental study and theoretical analysis on slender concrete-filled CFRP–PVC tubular columns

• This paper carried out the experiment of slender concrete-filled CFRP–PVC tubular (CFCT) columns under axial compression.
• A nonlinear finite element model (NFEM) of CFCT column was developed.
• The φ–λ model and the ultimate bearing capacity formula were proposed for slender CFCT columns.
• The ultimate bearing capacity formula is reliable in the fast prediction of the bearing capacity for CFCT columns.

This paper investigated on the performance of slender concrete-filled carbon fiber-reinforced polymer (CFRP)–PVC tubular columns under axial compression. Four specimens with different slenderness ratios were firstly carried out to explore their performance and failure modes under axial compressive loads in laboratory. Secondly, a nonlinear finite element model (NFEM) was developed to analyze the relation between loads and deformation, and the analytical values were compared with the experimental results. After the efficiency of NFEM was verified, the parametric analyses varying the number of CFRP layer, concrete compressive strength and the slenderness ratio were conducted by the NFEM, and the ultimate bearing capacity formula as well as the relation model of the stability coefficient (φ) versus slenderness ratios (λ) were proposed. To validate the efficiency, ultimate bearing capacity was compared among the experimental results, NFEM analytical values and the prediction by the proposed formula. The results indicate that not only the developed NFEM can effectively depict the varying process of the loads and deformation in details, but also the proposed ultimate bearing capacity formula is reasonable and reliable in the fast prediction of the bearing capacity for slender concrete-filled CFRP–PVC tubular columns. It is beneficial to widely apply such new type composite columns in pile foundation or corrosion environments.