Design of reinforced concrete columns subjected to biaxial bending

Biaxial bending in reinforced concrete columns in very complex. The Bresler Reciprocal Method (1) is a simplified approximate approach to analyze reinforced concrete columns in biaxial bending. In this thesis a spreadsheet is used to analyze rectangular reinforced concrete columns for biaxial bending and to compare its exact results to the approximate approach using the Bresler reciprocal method.

The results of comparisons confirmed what the ACI Building Code (3) indicated. The Bresler Reciprocal Method is a satisfactory and conservative method to use for biaxial bending and axial load, with a note that the method is “most suitable” when values of P_x and P_y are greater than the balanced axial load for that axis.