There is an excessive demand for the rehabilitation of frame-type RC buildings which do not satisfy current seismic code provisions. Therefore, it is imperative to develop user-friendly strengthening methodologies which do not necessitate the evacuation of the building during rehabilitation period. The aim of this study was to strengthen the masonry infill walls by means of diagonal carbon fiber-reinforced polymer fabrics and to integrate them with the existing structural frame in order to form a new lateral load resisting system. This study investigated the possible effects of height-to-width ratio of the infills on the overall behavior attained by the previously developed rehabilitation methodology. In the first part of the study, eight 1/3 scaled, one-bay, two-story RC frames with two different aspect ratios were tested. The experimental results in terms of lateral stiffness, strength, drift, and energy dissipation characteristics of the specimens were discussed. In the second part, a numerical study of the frames was conducted to estimate the non-linear behavior of the specimens.