Seismic design is followed in different countries on force based design with a final check on displacement. Linear elastic analysis is performed and the comparison of Response Reduction factor is calculated based on the National and International codes. Response reduction factor reflects the capability of structure to dissipate energy through inelastic behavior which accounts for the damping and ductility requirement. Building codes define R-factor based on type of structural system, material configuration, and detailing. Codes also differ in calculation of drift and allowable drift limit. R-factor from many developing countries are obtained from well developed countries which makes them more vulnerable towards earthquake and thus provides a false representation and thereafter it turns to be unrealistic. A parametric study involves modeling a dual system in ETABS and response spectrum analysis is carried out. This paper focuses on study of variation of base shear with R factors and its effect on membrane forces considered in design of members. A comparison of results is made using building codes IS 1893 and ASCE 7-10. The performance of building is verified using displacement modified approach.