Axial-Shear-Flexure Interaction Approach for Reinforced Concrete Columns

Abstract

This paper modifies the conventional section analysis approach for shear behavior to be applicable for displacement-based evaluation of reinforced concrete columns and beams subjected to shear, flexural, and axial loads. The proposed approach is based on principles of axial-shear-flexure interaction. Shear behavior is modeled by applying the modified compression field theory, and flexure behavior is modeled by employing the conventional section analysis. The mechanisms of shear and flexure are coupled as springs in series, considering axial deformation interaction and concrete strength degradation, and satisfying compatibility and equilibrium relationships. The proposed approach is simplified to enable modeling a reinforced concrete column using a single section analysis with a single shear model for the entire element. The simplified approach is employed for displacement-based analysis of shear- and flexure-dominated reinforced concrete columns previously tested. Analyses are also performed for reinforced concrete columns tested by other authors. In order to verify the new displacement-based approach, analytical results, such as ultimate lateral loads and drifts as well as post-peak responses, were compared and found consistent with experimental data for a series of reinforced concrete columns.