A Simplified Axial-Shear-Flexure Interaction Approach for Load and Displacement Capacity of Reinforced Concrete Columns

Abstract

A simple performance-based evaluation approach is presented based on interactions of axial, shear, and flexure mechanisms to estimate the axial and lateral deformation and load capacities of reinforced concrete columns. The developed model is based on a simplification of a consistent but relatively more complex approach known as the axial-shear-flexure interaction (ASFI) method, which is able to predict the full load-deformation response of reinforced concrete columns subjected to axial, flexure and shear force. The analytical model was developed by coupling an axial-shear model, which is a biaxial shear model, and an axial-flexure model, which is the traditional section analysis. Axial deformation interaction is the main compatibility condition taken into account in this approach. Equilibrium conditions are satisfied through a simple shear and flexure stress relation. A series of reinforced concrete columns subjected to axial and lateral loads, tested by various researchers, were evaluated by the simple developed approach and the results were compared with the test data; consistent correlation and agreement were achieved. This paper describes the formulation, implementation and verification of the modified approach. A future attempt is to modify the ASFI method for response estimation of reinforced concrete columns in fire under axial load and lateral deformation induced by thermal expansion.