Interface model for bond-slip and dowel-action behavior

This paper presents an interface element formulation for modeling dowel action and bond-slip behavior of steel reinforcing bars in the finite element analysis of concrete structures. The interface connects steel bar elements to concrete elements, and allows bar elements to have a smaller size than the concrete elements to which they are connected, to improve computational efficiency as well as flexibility in meshing. It adopts a cyclic bond stress-versus-slip law developed by the last two authors, and extends a dowel-action model developed for monotonic loading to cyclic loading. A numerical study has been conducted to demonstrate the benefits of using a bond-slip model in eliminating the mesh-size dependency of numerical results that can otherwise be introduced by bar elements directly connected to concrete elements and the accuracy and computational efficiency provided by the proposed interface formulation. The capability of the model to simulate dowel action has been validated with results from monotonic and cyclic shear loading tests performed on individual dowel bars, as well as shear keys in bridge abutments.