Damage-plastic model for concrete failure

The present paper deals with the combination of plasticity and damage applied to modeling of concrete failure. First, the local uniqueness conditions of two types of combinations of stress-based plasticity and strain-driven scalar damage are studied. Then a triaxial damage-plastic model for the failure of concrete is presented. The plasticity part is based on the effective stress and the damage model is driven by the plastic strain. The implementation of the model in the form of a fully implicit integration scheme is discussed and the corresponding algorithmic stiffness matrix is derived. The constitutive response is compared to a wide range of experimental results. Finally, the model is applied to the structural analysis of reinforced concrete columns. A regularized version of this model with weighted spatial averaging of the damage-driving variable is published in a separate paper.