Plane Stress Reinforced Concrete Finite Elements

A rational approach to the modeling of reinforced concrete finite elements for plane stress applications is presented. Both the nonhomogeneity and anisotropy due to the reinforcement and the effect of tension cracks in the concrete are considered. It is assumed that the reinforced concrete is an elastic material and the strain energy of the body exists only for the uncracked portion of the concrete and the steel embedded in the body. Since initially the extent of cracking in the concrete body is not known, an iterative solution scheme is employed. The general formulation of the procedure is outlined and a detailed development for both a constant strain triangular element and an arbitrarily reinforced rectangular element with a linear edge displacement variation is presented. A variation of the initial stress procedure is followed to predict the extent and location of the tension cracks. Several applications are included using the nonconstant strain rectangular element in order to confirm the validity of the method.