This paper presents a numerical and theoretical study from an ongoing research program focused on the structural behavior of austenitic stainless steel frames. Four different rectangular hollow sections (RHS) subjected to combined symmetrically concentrated vertical and lateral loads were studied. Taking into account material non-linearity and geometrical non-linearity, the influence of global sway imperfection (d) of the frame and local bow imperfection (d) of the member on the structural behavior of frames was analyzed. Based on global plastic analysis, second order effects under different loading cases of altering the loading position of vertical loads were studied. The finite element (FE) analysis software Abaqus was employed to simulate the in-plane structural behavior of all frames.