Biaxial Interaction and Load Contour Method of Reinforced Concrete T-Shaped Structural Walls

Reinforced concrete structural walls with T-shaped cross sections (or T-shaped walls) have been used as an efficient lateral force-resisting system for building structures. Such T-shaped walls are subjected to axial compression and combined bending moments about two orthogonal axes. In the present study, a straightforward design method for biaxially loaded T-shaped walls is developed by modifying the existing load contour method. First, a strain compatibility section analysis method that can estimate the biaxial bending resistances of arbitrary wall sections is developed and its validity is verified through comparisons with test results. Then, a parametric study is performed to investigate the interaction of biaxial moments at a constant axial load in T-shaped walls. The parametric results show that, due to the unsymmetrical geometry of T-shaped sections, the biaxial interaction depends significantly on the direction of moments and the magnitude of axial compression. Based on the results, the non-dimensional contour equations of biaxial moments for T-shaped walls are proposed and a design procedure of T-shaped walls is established.