In Memoriam of Prof. Dr. Bernt Johansson
The current design codes for steel reinforced concrete (SRC) columns are, in general, only applicable to normal-strength materials. In Eurocode 4, concrete grades C20/25 to C50/60 and steel grades S235 to S460 are allowed to be used in composite columns, whereas it is possible to use higher-strength concrete (up to C90/105) in Eurocode 2 and S690 steel in Eurocode 3. In this paper, an analytical method is proposed to predict the ultimate strength of SRC columns, taking into account the effect of strain compatibility and lateral confinement. A finite element model is developed to analyse the behaviour of SRC columns under axial loading using ABAQUS. The parametric studies are conducted by varying the diameter, spacing and volumetric ratio of the lateral reinforcement and the column length. It was found that the full plastic method given in EC4 overestimated the strength of SRC columns with high-strength steel. Nevertheless, the proposed method can predict the strength of SRC columns with concrete strengths up to 90 N/mm2 and steel strengths up to 690 N/mm2.