The development of design methods for seismic retrofitting of reinforced concrete structures wi̇th buckling restrained braces

RC structures are strong enough to withstand earthquakes with the current specification and construction techniques in Turkey earthquake-prone country. Researchers are aware, however, that existing deficient RC structures, especially those constructed prior to 1999, are hazardous to life and property. Column jacketing and shear walls are the most used retrofitting methods. However, during the application of these two methods, buildings cannot be used and must be evacuated. Particularly in public buildings, evacuation means the cessation of public services. Thus, it has become necessary in practice to use external strengthening methods for strengthening existing deficient structures. Steel buckling restrained braces (BRBs) are a novel type of brace that has been used in retrofitting solutions for decades. It is estimated that their tension and compression capacities are approximately the same, and their hysteretic behaviours are quite stable. This thesis includes both experimental and analytical studies. The ½ scale four two-storey deficient RC structures were constructed. These structures were threedimensional with 1x3 bays. One of these structures was tested without strengthening (reference structure) and the other two structures were retrofitted with BRB braced frames (BRBFs). The cyclic reversed static testing procedure was used during the experiments. The connection between the existing RC structure and newly added BRBFs was achieved by using anchorage rods. The lateral load was applied to the RC structure and then the force was transferred from the RC structure to the BRBFs via the anchorage rods. Furthermore, newly constructed RC foundations were also used for the BRBFs. The test results indicated that the lateral strength and stiffness and energy dissipation capacity of the retrofitted structure with BRBFs increased significantly. Additionally, the BRBs yielded significantly before the RC columns were severely damaged. Furthermore, the analytical study indicated that the behaviour of the retrofitted structure can be simulated using a computer program. As a result, it is possible to evaluate the structure's performance. Based on the findings of this study, a design procedure for external retrofitting with BRBFs is proposed.