FE analysis of failure behaviour of reinforced concrete columns under eccentric compression

Paper presents results of FE modelling of failure behaviour of reinforced concrete columns under eccentric compression. Concrete was described with an elasto-plastic model using isotropic hardening and softening. A Drucker–Prager criterion with a nonassociated flow rule was defined in a compressive regime and a Rankine criterion with an associated flow rule adopted in a tensile regime. To ensure the mesh-independence and to capture strain localization in concrete, both criteria were extended by a characteristic length of microstructure in a softening regime with the aid of a non-local theory. The reinforcement was described with an elastic-ideally plastic constitutive law by von Mises. Two-dimensional plane strain and three-dimensional simulations were performed. The FE-calculations were carried out with a different characteristic length of micro-structure, reinforcement ratio, column slenderness, load eccentricity, distribution of the tensile strength, bond-slip between concrete and reinforcement and fracture energy. The FE results were quantitatively compared with those from laboratory experiments performed by Kim and Yang [Kim J, Yang J. Buckling behaviour of slender high-strength concrete columns. Engineering Structures 1995;17(1):39–51]. A satisfactory agreement was achieved.