Reinforced concrete (RC) shear walls are a common lateral load resisting structural system widely used in seismically active regions. Despite the advancements in modern seismic design provisions used around the world, there is still a large inventory of RC shear wall structures designed based on older, less stringent design guidelines. Part I of this thesis describes the results of an experimental study on the effectiveness of using externally bonded carbon fibre-reinforced polymer (CFRP) sheets to enhance the seismic performance of non-ductile reinforced concrete (RC) shear walls representative of low aspect ratio walls. Nine 2/3 scale RC shear wall specimens were designed to replicate structural deficiencies commonly found in older RC shear wall structures, including insufficient shear reinforcement, lack of boundary elements, lap splices within the potential plastic hinge region, and low concrete compressive strength. The wall specimens were repaired or strengthened using vertical and horizontal CFRP sheets and then cyclically tested to simulate seismic loading. Experimental results demonstrate that the CFRP retrofitting system is able to restore the original strength and initial stiffness of severely damage specimens and significantly increase the strength, ductility, and energy dissipation capacity in strengthening applications. Part II of this thesis examines the use of hybrid simulation to capture the earthquake response of a multi-storey RC shear wall structure. Hybrid simulation combines analytical modelling and experimental testing to analyze the response of a complete structural system. In this approach, hybrid simulation is able to capture the exact nonlinear behaviour of complex structural components or subassemblies through testing while at the same time supplementing it with simulation of the rest of the structure through computer modelling to capture the global response of an entire structure. The experimentally tested shear wall is taken from a three-story prototype structure. In the hybrid simulation, the first story shear wall is experimentally tested at 2/5 of its original scale and the remaining two stories of the shear wall are modelled analytically using multi-layered shell elements in OpenSees. Results of the study demonstrate that it is feasible to use hybrid simulation to capture the seismic response of a RC shear wall structure.