COMPARISON AMONG FIVE CONSTITUTIVE MODELS IN FINITE ELEMENT ANALYSES OF CONCRETE-FILLED STEEL TUBE

The paper has carried out finite element analyses (FEA) of the axial strengths of square and rectangular concrete-filled steel tubular (CFT) stub columns with and with no binding bars by adopting five models respectively including three classical models — Von Mises, Mohr Coulomb, and Drucker Prager as well as two models proposed for concrete — Smeared Cracking and Damaged Plasticity, has described the features of each model, and has made comparison between the axial strengths of FEA and the previous experiments of 47 CFT stub columns. The results show that Von Mises model regardless of hydrostatic stress and concrete plastic volume dilatancy can not consider the confinement of core concrete and the influence of binding bars. The axial strengths predicted by FEA using Smeared Cracking model with associated flow underestimating the plastic volume dilatancy are slightly lower than the experimental results. Because of the consideration of hydrostatic stress and volume dilatancy, the rest three models with non-associated flow agree better with the experimental results, and there is a little difference between these three models.