In the first report, the nonlinear behavior of perfect plates and perfect stiffened plates (without initial imperfections) subjected to inplane loads were studied and idealized. Basic versions of two idealized units (elements) : the “rectangular plate unit” and the “stiffened plate unit”, have been developed. In this report, the capabilities of these idealized elements are extended so that they can be accurately applied to a wider range of actual structures. Effects of initial imperfections, i. e. initial deflection and welding residual stress, on the behavior of these elements are studied, idealized and included in the formulation. Lateral load is also considered and its interaction with initial imperfections and inplane load is taken into account. Assessment of accuracy of these elements is carried out through comparisons with experimental and other theoretical results. An example of analysis on a relatively large structure is also presented to demonstrate the capabilities and efficiency of these elements.