From recent earthquake experiences, buildings with structural walls do have satisfactoryrnperformance against collapse. However, this is not always true for dual structures composedrnof both structural walls and frames resisting seismic actions. This begs for a detailed study onrnthe performance of dual structures. Some studies show that the elastic response of dualrnbuildings is mainly governed by the wall response and the frame contribution could bernneglected, which then makes them a secondary seismic member. This scenario is reversedrnwhile the members are within their inelastic nature. These variations make it difficult tornselect and identify primary and secondary members based on stiffness limitation specified inrncodes which is only based on the linear response of the members. Without clearly identifyingrnthe distinction between these members in a structure, and without clearly knowing thernboundary between these seismic members it is difficult to follow the simplified approaches ofrnanalysis in practice, in which lateral load is resisted by some selected and properly detailedrnmembers. rnHence, to address the effect of considering frames as secondary seismic members in RC wallframernsystem,rncomparativernanalysisrnamongrnsamplerndualrnsystemrnbuildingsrnhasrnbeenrncarried outrnrninrnrnthe following thesis work. Efforts have been made to evaluate the overall seismicrnperformance of the buildings using non-linear push over analysis method. For each buildingrnunder study two cases are examined. In the first case frames and shear walls are designed andrndetailed as primary seismic members. In the second case however, frames are designed asrnsecondary seismic members and shear walls are designed and detailed to be primary seismicrnresistance contributors. The results of non-linear push over analysis were obtained for eachrncase in the form of capacity curves, global yielding point and performance point, plasticrnhinge formation patterns, and base shear distribution among frames and walls. rnThe observation of these results shows that the overall seismic resistance capacity ofrnbuildings reduces when frames are considered as secondary seismic members. In conclusionrnof this study; in RC wall-frame dual system, it is important to design both frames and walls asrnprimary seismic members. rnIn addition, frames take up larger bases shear in the inelastic range than what is estimated inrnthe linear analysis, which makes it incorrect to regard these members as secondary seismicrnmembers according to most building codes specification of base shear resistance proportion between primary and secondary members. To minimize the effect of neglecting frames asrnsecondary members, the stiffness limitation specified in code should be revised.