Localization Characteristics of Triaxial Concrete Model

The paper examines different failure modes when concrete materials are subjected to triaxial load scenarios in uniaxial and confined compression, in direct tension, as well as in shear. The different failure modes are studied with the aid of a novel concrete model that describes the hardening/softening behavior of concrete in tension, low-confined compression, that captures the transition from brittle to ductile failure with increasing confinement and that expands the triangular deviatoric section in tension to the circular one in high confined compression. The nonassociated plasticity formulation is based on a smooth three-invariant loading function that is C1-continuous in stress-space except for the vertex at the point of equitriaxial tension. The paper concludes with an in-depth discussion of localization properties of concrete materials under tension, compression, and shear.