Simplified biaxial column interaction charts

Abstract

This paper presents a novel analytical method to generate interaction diagrams useful for the design of reinforced concrete (RC) biaxial columns. Due to the introduction of new classes in concrete compressive strength (fc') with somewhat different parameters for the steel grades (fy), it has become necessary to develop new interaction diagrams. The interaction diagram of any desired level of gamma (γ) can be generated to find the required axial load capacity (Pc) and moment capacity (Mcx, Mcy) of the columns having different reinforcement ratios (ρ). In addition, this study reports some numerical examples using the proposed interaction charts (Reciprocal as well as the equivalent uniaxial eccentricity method) to find the values of Pc and (Mcx, Mcy) for the columns subjected to biaxial bending. The obtained results are compared with a conventional method (ie, the computer software SP‐Column). The obtained results are promising, as the values obtained by the Interaction Charts and the conventional method appear to be in good agreement.

Keywords

• axial load capacity
• biaxial columns
• equivalent uniaxial eccentricity
• interaction charts
• moment capacity