Finite element modelling of concrete-filled steel stub columns under axial compression

• The existing FE model only gives reasonable predictions for normal CFST columns.
• A new FE model was developed for CFST stub columns.
• Dilation angle used in the concrete model was calibrated against test data.
• A new concrete stress–strain model was developed.

Due to the passive confinement provided by the steel jacket for the concrete core, the behaviour of the concrete in a concrete-filled steel tubular (CFST) column is always very challenging to be accurately modelled. Although considerable efforts have been made in the past to develop finite element (FE) models for CFST columns, these models may not be suitable to be used in some cases, especially when considering the fast development and utilisation of high-strength concrete and/or thin-walled steel tubes in recent times. A wide range of experimental data is collected in this paper and used to develop refined FE models to simulate CFST stub columns under axial compression. The simulation is based on the concrete damaged plasticity material model, where a new strain hardening/softening function is developed for confined concrete and new models are introduced for a few material parameters used in the concrete model. The prediction accuracy from the current model is compared with that of an existing FE model, which has been well established and widely used by many researchers. The comparison indicates that the new model is more versatile and accurate to be used in modelling CFST stub columns, even when high-strength concrete and/or thin-walled tubes are used.