Load contour method for biaxial design of reinforced concrete L-shaped structural walls

Biaxial behavior of L-shaped walls differs from that of rectangular or circular columns with symmetrical solid sections, due to the unsymmetrical section geometry. In this study, a straightforward design method for biaxially loaded L-shaped walls is developed by modifying the existing load contour method. Using the strain-compatibility section analysis method, a parametric study on the prototype L-shaped walls is performed to investigate the interaction of biaxial moment strengths at constant axial load. The results show that, due to the unsymmetrical section geometry of L-shaped walls, the contour of biaxial moment strengths is highly unsymmetrical in shape and significantly affected by the moment directions and axial loads. Based on the results, elliptical contour equations for the biaxial moment strengths of L-shaped walls are proposed. In addition, a design example illustrating the biaxial design procedure using the proposed method is given.