Reinforced concrete buildings that are not properly designed, constructed, or supervised, might not have the resistance to bear even their own weight. When the effects of deformation in the concrete over time are added to the loads, great damages and even collapses can be seen. In this study, the performance of reinforced concrete buildings under axial loads was investigated. The effect of creep in concrete over time was also evaluated. Creep deformation has been integrated into the analysis with a simple method. A total number of 20 8-storey reinforced concrete frame buildings were modeled via ETABS. In each model, only column dimensions and concrete compressive strengths have been changed. The models were analyzed under the combined effect of axial loads and creep. As a result, the effect of concrete compressive strength and column dimensions on collapse in reinforced concrete buildings under the mentioned effects was examined. The results showed that column dimensions should be much high to prevent collapse when low strength concrete is used in buildings. In addition, a formula that can be used to determine the parameters of concrete quality and column cross-sectional areas required against collapse is proposed for the preliminary design of similar types of buildings.