Strength and ductility of rectangular concrete columns: A plasticity approach

The theory of plasticity and the deformation compatibility equations are used to evaluate the development of lateral confinement of rectangular concrete columns and the resulting increases in strength and ductility. Concrete is modeled as an elastoplastic, strain hardening/softening material, with stress-path dependent strength and a nonassociative flow rule. The geometric modeling concentrates of the effects of the arrangement of transverse reinforcement on the type and magnitude of lateral confinement. The solution is based on the coupling of the elastoplastic relations for concrete and steel, and the compatibility of deformations of the concrete core and the transverse reinforcement. The ability of the method to predict the response of confined compression members is demonstrated based on several published experimental results.