Numerical modelling of concrete-filled steel tubular short columns under axial compression

The paper presents three-dimensional numerical models of short concrete-filled steel tubular circular columns that can successfully describe the column behaviour under axial compression. Several of the most commonly used material models for the steel part and a concrete portion of the column are evaluated in the models. In addition, the paper presents a new proposal for the extension of the Eurocode 2 stress-strain relation to make it suitable for describing the complex behaviour of concrete inside the steel tube. This model overcomes the current limitations of the Eurocode 2 design guide, referring to the limitation for the concrete curve in compression to 3.5‰ strain. The ultimate axial column strength obtained by the proposed model is compared to the ultimate column capacity calculated by a simplified method provided in Eurocode 4. All presented numerical models are validated on a set of experiments from the literature and demonstrate good agreement. The comments about the accuracy of each model are provided, along with the identified limitations