A seismic retrofit scheme for seismically-weak reinforced concrete（ RC） frame was proposed.The presented method utilized buckling-restrained brace（ BRB） to globally enhance lateral strength and overall energy dissipation capacity of the RC frame

and steel caging was further utilized to locally improve flexural and shear strength of columns. An open-source earthquake engineering simulation system OpenSees was used to develop numerical models of a bare RC frame and a RC frame retrofitted with BRB. The numerical models were developed to simulate seismic behaviors of the RC frames. A simple inelastic truss element was used to simulate the BRB. Confinement of steel cage was taken into consideration in calculating material properties of the column’s concrete of retrofitted frame. Comparisons of numerical results with that of cyclic tests on the RC frames were conducted. The effects of the BRB and steel caging on seismic performance of RC frames were also investigated. It is shown that good agreements were obtained between numerical and experimental results. The numerical models based on OpenSees were able to predict the seismic behaviors of the RC frames with acceptable accuracy. Steel caging effectively improved flexural strength and deformation capacity of the deficient columns of the RC frame. The BRB significantly increased lateral stiffness

lateral strength

and energy dissipation capacity of the retrofitted frame.