Towards a unified mechanical model for design and assessment of structural concrete members under shear, flexure and punching

Abstract

A mechanical shear model for structural concrete members with and without stirrups is presented, which incorporates the most relevant shear transfer mechanisms. The model is based on the principles of structural mechanics, on a number of assumptions supported by the observed experimental behaviour and by the results of refined numerical models. Simple, direct and robust expressions are derived for shear strength verification and for design of the transverse reinforcement. The general theory behind the model enables it for steel or FRP simply supported or continuous, reinforced or prestressed concrete members, with any cross section, subjected to distributed and point loads or to axial forces. Excellent agreement between the results of a large number of shear tests and the model predictions has been obtained. The model is currently being extended to punching of slabs, for which the critical perimeter is obtained as a result of the model formulation