A nonlinear finite element (FE) study of concrete-filled steel elliptical hollow section (EHS) beam-columns is presented in this paper. First, a summary of experiments conducted on a total of 27 EHS specimens with varying lengths and different load eccentricities, with seven of the tested specimens containing steel reinforcement, is presented. These results, together with other results from the literature, were used to validate a nonlinear finite element model developed in ABAQUS, which incorporated steel material properties obtained from tensile testing and a confined concrete model calibrated with measured concrete strengths. The numerical results were found to agree well with those obtained from the experiments when comparing ultimate loads, load–deflection behaviour and failure modes. Upon validation of the models, an extensive parametric study comprising 240 simulations was conducted to investigate the effects of cross-section slenderness, nondimensional member slenderness, loading eccentricities and embedded reinforcement. Both the experimental and numerical results have been used as the basis for developing simplified design rules for inclusion in codes such as EN 1994-1-1.</p
