Most existing structures are not designed with cod requirements to meet seismic risk, Therefor methods for strengthening and stiffening existing buildings are important . This study is comparing between strengthening by adding shear wall or by adding steel bracing.X -V The study shows the importance of using steel bracing system that is excellent approach for strengthening and stiffening existing buildings with small increase in mass ,the study also approved that the constant value of R(response factor)(as mentioned in the Syrian code and UBC97) is not completely correct.