Axial behaviour of circular steel tubed concrete stub columns confined by CFRP materials

Carbon fibre reinforced polymer material has many advantages, including high strength, light weight and good durability, resulting in good performance when it is used in concrete structures; however, the construction procedures of concrete columns confined by a CFRP tube are very complicated, leading to a relatively high cost. Therefore, CFRP-steel composite tubed concrete columns are suitable for application in concrete structures because of their excellent mechanical properties and convenient construction. In this paper, the axial static mechanical behaviour of circular CFRP-steel composite tubed concrete stub columns was investigated, including an experimental study and a theoretical analysis. Based on investigation of the strain efficiency of CFRP material, the calculation methods for the axial ultimate loading capacity of circular CFRP-steel composite tubed concrete stub columns were compared, and recommendations for practical design were provided.