Simulation of Punching Failure in Reinforced-Concrete Structures

Abstract

A numerical model has been developed to reproduce the punching failure in reinforced-concrete structures. It is characterized by an efficient triaxial strength criterion for concrete, a nonassociated flow rule reproducing the concrete dilatancy observed experimentally, and a cracking model accounting for the brittleness of concrete failure under various states of stress. The simulation of punching failure in a circular slab is successfully performed as the localized mode of failure—characterized by an inclined crack—is reproduced. It is shown that punching failure is initiated by the coalescence of microcracks inside the slab, followed by a crack propagation towards the corner of the slab-column intersection. A parametric analysis of the punching failure demonstrates that (1) punching failure is due to tensile failure of concrete along the inclined punching crack and is not due to compressive failure; (2) increasing the percentage of reinforcement reduces the state of internal cracking resulting in an increase of the failure load and a reduction of the ductility; and (3) the size effect observed experimentally is reproduced and a size-effect law is proposed.