Seismic Retrofit of Concrete Block Wall Intersections Using Composite Laminates

An experimental study was conducted to investigate the effectiveness of strengthening the intersection of flanged concrete block shear walls using surface-bonded composite laminates. A total of 15 specially designed flange-web intersecting wall specimens were tested using four different retrofit schemes. Tests included wall intersections reinforced with unidirectional laminate with the fibers oriented perpendicular to loading direction (90°), and bi-directional laminate with orientations of (90°/0°), (90°/0°) ² , and (45°/135°) to the applied load direction. The behavior of each specimen type is discussed with respect to its failure mode, strength, and deformation characteristics. Results showed that the composite laminates significantly increased the shear strength of concrete block shear wall intersections. In addition, the fiber orientation influenced the failure mode and controlled the development of the post-peak deformation capacity of the flange-web intersection. The improved post-peak behavior demonstrated the benefits of retrofitting concrete block wall intersections for strength enhancement. The retrofit scheme resulted in 100%—400% increase in strength compared to non-retrofitted specimens constructed with traditional steel joint reinforcement.