This study proposed a practical seismic retrofit method for RC frames. For this purpose, a quasi-static loading was applied to 8 RC frames in finite element analysis software, Abaqus, and frames were pushed 45 mm laterally. High-strength fiber-reinforced lightweight concrete panels strengthened infill walls inside the RC frames. To apply them to the walls, epoxy binder and polyurethane binder were used, and their behavior was compared. Using panels increased the lateral load capacity of the whole frame according to the numerical analysis performed with Abaqus. In the worst case, the retrofitted frame carried approximately two times the traditionally infilled frame's capacity. In the best case, the RC frame carried 4.29 times the lateral load traditionally infilled frame. Polyurethane binder prevented the separation of panels from walls and provided a ductile behavior to frames even in large drifts.