This research presents an investigation through a numerical study on the effect of two parameters; stiffness of columns and number of stories on both base shear force and top displacement of buildings. In this study, two dimensional models were used with varying number of stories (6, 12, 20 and 30) and varying column cross sections. The results proved that these two parameters have significant impact on both base shear and top displacements. Results show a difference between actual seismic behavior and the resulted seismic behavior from traditional code method, which reflects on economic designs of such structures.