This　paper　mainly　studied　the　problems　and　demand　of　seismic　strengthening　of　RC　frame　structure,　and　proposed　a　fast　and　efficient　seismic　strengthening　method,　which　used　the　concrete-tube　buckling-restrained　braces　and　buckling-restrained　braced　frames.　Three　frame　specimens　were　designed,　manufactured　and　tested　under　reversed　cyclic　loadings,　including　one　original　frame　and　two　buckling-restrained　braced　frames　with　different　brace　types,　i.e.　monoclinic　brace　and　herringbone　brace.　The　test　demonstrates　the　feasibility　of　the　additional　buckling-restrained　braced　frames,　which　was　designed　according　to　this　paper.　Seismic　performances　of　the　additional　buckling-restrained　braced　frames,　such　as　concrete　element　cracks,　lateral　load-displacement　loops,　skeleton　curves,　BRB　load-deformations　forces　of　RC　frame,　the　equivalent　viscous　damping　ratio　and　tangent　stiffness,　etc,　were　studied.　The　results　show　that　the　additional　buckling-restrained　braced　frames,　the　embedded　parts　and　the　connecting　constructions　are　reliable,　and　the　additional　buckling-restrained　braced　frames　show　excellent　seismic　force　reduction　and　energy　dissipation　capacity.　The　system　has　rich　and　stable　hysteretic　load-displacement　curves.　The　BRB　yields　at　low　inter-story　drift　angle,　and　can　keep　effective　at　large　lateral　inter-story　drift　angle.　It　is　validated　that　the　equivalent　viscous　damping　can　thus　be　increased,　the　seismic　response　be　reduced,　and　then　the　structural　performance　be　improved.