Behavior of Reinforced Concrete Frames Retrofitted with Shotcrete Panels Connected Only to the Beams

Abstract

Over the past years, several retrofitting techniques have been used to retrofit vulnerable reinforced concrete (RC) structures. Application of shotcrete on the walls is a known retrofitting technique which is used on existing RC or masonry buildings. In this study, wet-mixed reinforced shotcrete panel is used as a retrofitting measure in RC frames. The presented experimental work is composed of strengthening one virgin and one damaged bare frames with the shotcrete panel. Nearly \({\frac{1}{2}}\) scale, one story and one bay specimens were tested under constant vertical loads acting on the columns and lateral reversed cycling loads acting at the slab level. The shotcrete panel is placed distanced to the columns and is connected only to the beam and to the foundation. To assess the effect of the retrofitting technique, the results of the specimens retrofitted with shotcrete panel were compared with the bare frame and the reinforced concrete wall. The results of the experiments show that the lateral load carrying capacities of the retrofitted frames are approximately 60 % more than that of the bare one and 30 % less than the concrete wall. In addition to the experimental works, an analytical model is developed considering the experimental results. Changes in distance between the columns and shotcrete panel are studied analytically to reveal how it affects the overall behavior of the retrofitted frames.