A state-of-the-art review on shear-friction

Initially proposed in 1966, the “shear-friction theory” has been adopted in all design codes to analyse concrete-to-concrete interfaces. In the last decades, several improvements were suggested to take into account more influencing factors, to increase the accuracy and to enlarge the application field. The inclusion of the concrete strength and density and the consideration of the dowel action are examples of the proposed improvements.This paper presents a literature review on design expressions for shear-friction, chronologically ordered, describing proposals from the earliest research studies, precursors of the theory, until the most recent studies, incorporated in the newest fib Model Code. The most significant contributions are identified and a comparison between some of these design expressions is presented. Codes updates concerning shear-friction provisions are also identified in the literature review herein presented.

► The shear-friction theory is currently adopted by all major design codes.
► Several improvements were proposed in the last five decades to increase the accuracy of design expressions.
► Dowel action is usually neglected and not explicitly considered in design expressions.
► Model Code 2010 presents a new design expression and an alternative methodology to assess the roughness of the interface surface.