The evaluation of progressive collapse on a RC buildings under the effect of static pushover on RC buildings with slab and the RC buildings without slab following an initial local damage. In order to evaluate the effects of initial damage location on progressive collapse of building structures of different story RC buildings from 1-story to 5-story for each case; one is RC building with slab and the other RC building without slab. Using an analytical model of the structures based on the knowledge gained in this study, the total of 25 initial damage scenarios structures are analyzed.On the RC building structures with slab the Vierendeel frame action is found to be the dominant progressive collapse resisting mechanism following element removal in all evaluated RC frame structures with slab but on RC frame structures without slab only one case that the vierendeel frame action is found. The 1-story structures are found to be susceptible to collapse under the initial damage scenario of corner column removal and middle column on both case with slab and without slab. The capability of the structure to develop Vierendeel Frame Action is crucial in resisting progressive collapse. Structures are less susceptible to collapse if there are at least two floors (and connecting columns) above the removed column such that Vierendeel frame action can effectively develop. Vierendeel Frame Action has no effect on RC building without slab.The 5-story frame experienced small deformations and resisted collapse after being subjected a column removal on its first floor.The RC frame structures with slab have small vertical displacement than the RC frame structures without slab, and this is due to the fact that the intern connection between the slab, beam and column allow the sharing of intern forces and that result to the pulling of the structures to limit the displacement of other element after the column is removed.