chapter  8
Pages 39

High-strength composites have been very effective in retrofitting columns to improve earthquake resistance. A large number of investigations conducted in the laboratory and field applications in buildings and bridges established the viability of composites for improving the performance of axially loaded members (ACI Committee 440, 2002). The composites are essentially used to confine the concrete, resulting in improvement of (i) compressive strength or axial force capacity, (ii) flexural and shear strength, (iii) flexural ductility, and (iv) performance of lap splices. Composites can also be used to repair and rehabilitate cap beams and beam-column joints.