A simple rational method is developed in this study to simulate the shear and bending behaviours of Steel Plate Wall (SPW) systems, and is referred to as the Modified Plate-Frame-Interaction (M-PFI) model. The model can determine force and displacement values that corresponded to pre- and post-critical buckling state, post-yield state and ultimate capacity of individual panels. Using the M-PFI model, design requirements of the beams and columns were determined. A new mathematical formulation was presented to determine the angle of inclination of the tension field. The M-PFI concept was...