Seismic Retrofit of Deficient RC Sear Walls with FRP Tow Sheets

This paper presents the results of a comprehensive study on the repair and strengthening of seismically deficient, reinforced-concrete (RC) shear walls using externally bonded fibrereinforced polymer (FRP) tow sheets. The shear wall specimens had structural deficiencies typically found in buildings designed using older construction codes, such as non-ductile details and insufficient shear reinforcement. The study comprises both analytical and experimental components. In the experimental component, sixteen shear wall specimens with different heightto-length aspect ratios (varying between 1.20 and 0.68) are subjected to in-plane, cyclic loading until failure, and externally bonded FRP sheets oriented in the vertical and horizontal directions are used to enhance the seismic response of the walls. In the analytical component, pre- and post-test finite-element simulations are conducted to predict and simulate, respectively, key parameters of the structural response of the FRP-reinforced walls (such as nonlinear forcedisplacement relationships and modes of failure). The test show that the FRP system is effective in preventing premature shear failure in the wall specimens, significantly increasing their energy dissipation capacity and enhancing their stiffness and flexural strength. Satisfactory correlation was found between the analytical prediction and the actual response observed during the tests, satisfactorily capturing and modelling the nonlinear response of repaired and strengthened walls, failure modes, debonding progression and strain profile distributions. The study shows that the FRP system is an attractive option to retrofit shear wall structures that might exhibit seismic vulnerabilities.