Modeling dowel action of reinforcement bars for finite element analysis of concrete structures

Abstract

A numerical model for the dowel action of reinforcement bars crossing cracks in concrete is developed for finite element analysis of concrete structures. The beam on elastic foundation theory is used to derive the dowel force-displacement relationship, which is expressed in a smeared form in terms of dowel stress and strain in order to be compatible with the smeared crack and smeared reinforcement models commonly used in finite element analysis. This dowel action model is incorporated in a finite element program that employs secant stiffness formulation and a displacement controlled iteration scheme for nonlinear analysis. Using the finite element program, the nonlinear behaviors of several reinforced concrete beams tested by others are analyzed well into the post-peak range. The beams are analyzed first with the dowel action neglected and then again with the dowel action incorporated. It is found that in certain cases, the dowel action can have significant effects on the shear strength and ductility of reinforced concrete beams and that the analytical results generally agree better with the experimental values when the dowel action is taken into account.