In this study main attention is focused on axial load carrying capacity of steel columns. Towards this aim, employing nonlinear geometric and material properties Finite Element models are generated using ANSYS program. In simulations due to its advantages Arc-Length method is utilized for determination of axial load capacity of columns. Computational study consists of four phases. In the first one nonlinear bucking loads of IPE 200 section are evaluated for different slenderness ratios (L/ry). Obtained results for different slenderness ratios are assessed against LRFD and Eurocode-3 specifications. In the second section geometrical imperfections are incorporated into column models in a systematic manner and capacity changes are evaluated. Effects of eccentric compression loadings on the axial load carrying capacity are studied in third section. Fourth section introduces the effects of combined geometrical imperfections and eccentric loadings.