The seismic performance of reinforced concrete frames designed for gravity loads is evaluated experimentally using a shake table. Two 1:3 scale models of one-bay, three-storied space frames, one without infill and the other with a brick masonry infill in the first and second floors, are tested under excitation equivalent to the spectrum given in IS 1893-2002. From the measured response of the models during excitation, the shear force, interstory drift, and stiffness are evaluated. The effect of masonry infill on the seismic performance of reinforced concrete frames is also investigated. Then, the frames are tested to failure. Severe damage is observed in the columns in the ground floor. The damaged columns are strengthened by a reinforced concrete jacket. The frames are again tested under the same earthquake excitations. The test results showed that the retrofitted frames could sustain low to medium seismic forces due to a significant increase in strength and stiffness. © ASCE.