Strength and ductility type retrofit of soft-first-story RC frames through the steel-jacketed non-reinforced thick hybrid wall

摘要

In this paper, a new technique is proposed for retrofitting low-rise soft-first-story reinforced concrete buildings. The proposed retrofitting technique is called "Thick Hybrid Wall". In this method, channel-shaped steel plates jacket boundary RC columns of a bare frame. The steel plates are extended to the bay of the frame through the additional steel plates connected together with the help of bolts. Then, additional concrete is cast in the provided steel formworks. To verify the efficiency of the proposed technique, one non-retrofitted specimen and four retrofitted specimens were tested under cyclic horizontal loading and constant axial forces. The observed experimental results determined that the thick hybrid walls not only increase the lateral strength and stiffness of the frames, but also considerably improve the lateral ductility. In addition to obtaining superior structural performance, the proposed method provides ease in construction at a building site, and minimizes the vibration, noise, and concrete dust of the retrofitting operation. The proposed method has the potential of significant reduction in construction costs of retrofitting existing buildings.