Modern seismic codes try to avoid story mechanisms by applying strong column-weak beam hierarchy. The structural design concerned with the failure mode control has been mainly treated through simplified rules provided in seismic codes. With this respect, the current strong column-weak beam design criterion presents a single value as the acceptance limit of strength ratios for all moment frames, even though the inelastic behavior of frames vary with many factors such as the height of frames. Studies have also shown that the capacity of structures in one or another way is related to the values of strong column-weak beam (SCWB) ratio. The relationship could be more biased if slab contribution in the design and analysis of moment frames is improperly handled. This is because the strong column-weak beam criterion can be highly affected by the extent to which slab contribution in lateral load resistance is considered. The contribution of slab in lateral load resistance is considered in this study both at the design and analysis stages. Having the slab contribution in to consideration this thesis work aims at studying the significance of increasing SCWB ratio in the means of preventing story mechanism. In the meantime the relationship between the minimum SCWB ratio provided by Eurocode 8 and the safety against collapse risks is studied. For this purpose plane reinforced concrete moment frames are designed and detailed according to the capacity design requirements of Eurocodes. The performance of the structures is evaluated by means of compliance to damage limitation and deformation capacity requirements of Eurocode 8. A nonlinear static analysis was performed on each structure using SeismoStruct analysis software. From the results of the static pushover analysis, capacity curves and the pattern of yielding and chord rotation hinges were obtained. The results indicated that the current minimum SCWB capacity design requirements in the Eurocodes provisions do not result in a collapse mechanism that involves all stories of the building. As height of a structure increased, the benefit of increasing the SCWB ratios decreased. For a given SCWB ratio, however, the taller structures have a lower risk of collapse. Significant benefits in collapse performance could be gained by increasing the minimum SCWB ratio beyond to 2.0.