## 3 Cyclic Behaviour of a RC One-Bay, One-Story Frame Retrofitted with an RC Infill Panel  
In this section, the impact of the studied particular retrofit consisting of constructing an RC infill within the bay of an existing RC frame is investigated [56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66] as a countermeasure of the presence of the soft story. This is done through an experimental study employing 1/3 scaled single-story, one-bay RC frames, described in Section 3.1., in order to identify significant nonlinear mechanisms from the interaction of the RC infills with the surrounding frame and to quantify the result of such a retrofit on stiffness, strength, ductility, and energy consumption. This retrofitting scheme is usually combined with the jacketing of the columns or beams of the surrounding frame. [PERSON] et al. [57] conducted a series of experiments employing one-bay, single-story scaled RC frames having RC-IP, which were connected by using various structural details to the surrounding frame. They concluded that the addition of an RC infill wall significantly reduced the drift and improved the stiffness and the ultimate strength. Moreover, they observed that the failure mode of the RC infill walls was dominated by a shear compression effect. [PERSON] and [PERSON] [58] and [PERSON], [PERSON], and [PERSON] [59] conducted a series of experiments with 1/3 scaled one-bay RC frames, of either one or two stories, including RC infills in various forms that replicated door and window openings. They concluded that such infills increased substantially the stiffness,  
Figure 9: Out-of-plane collapse of unreinforced masonry infills (UMI) panles from RC frame structures due to earthquake excitation. strength, and energy dissipation of these frames with RC infills when compared with the corresponding bare frames. They also performed analytical studies and predicted quite successfully the strength of these RC infilled frames. [PERSON] [60] and [PERSON] et al. [61; 62] investigated the behaviour of RC infilled frames located at the ground floor of buildings subjected to cyclic seismic-type loads. These RC infills were either not connected or connected with the surrounding frame being retrofitted with RC jackets. This manuscript is a summary of the findings of this investigation. [PERSON] et al. [63] proposed calculation models for the yield moment, the secant-to-yield-point-stiffness, the cyclic ultimate chord rotation, and the shear resistance (due to diagonal tension, shear sliding, squat-wall effects, etc.) of the composite wall produced by infilling the space between two RC columns with RC panels without encapsulating them. They validated this methodology by comparing their predictions with experimental measurements. [PERSON] et al. [64] and [PERSON] et al. [65] employed the diagonal strut model, broadly used as a design tool in the case of masonry-infilled RC frames, for the design of reinforced concrete (RC)-infilled frames. They conducted an extensive literature review and an experimental investigation to support this study, concluding that for the best performance of an RC-infilled frame with non-ductile members, the columns should be strengthened with RC jackets concurrently with the casting of the RC infill. Furthermore, the RC infill should be connected to the frame through dowels, preferably only along the horizontal interfaces with the frame, in order to avoid early failure in the columns. They also concluded that the failure of RC-infilled frames with non-ductile reinforcement detailing is likely to occur in a frame component and not in the infill. [PERSON] et al. [66] employed the pseudo-dynamic method to test a full-scale 3-D RC four-story building, having the central bay of two opposite three-bay frames retrofitted with RC infills. They used different connection details between the RC infill and the surrounding frame as well as reinforcement percentages for the two infilled frames.