The seismic analysis of reinforced concrete infilled frame strengthened by using
steel cage and expanded metal was investigated. The strengthening technique of steel cage
consisted of steel angle, batten and expanded metal sheet was employed. The brick infill
panel was strengthened with ferrocement and expanded metal. The flexible base
foundation was considered by modelling the pile foundation with the lateral and the
vertical spring stiffness. Eight types of frames: four existing frames and four retrofit
frames were analyzed by nonlinear static analysis and nonlinear time history analysis with
20 ground motion records. It was found that the initial stiffness and the strength of the
retrofit frames were significantly higher than those of the existing frames. The observed
seismic damage of the retrofit frames was decreased to the specified limit. The initial
stiffness of the frames with flexible foundation was lower than that of the fixed base
resulting to the larger displacement and the higher seismic damage of the structures.