The document reviews different techniques for retrofitting reinforced concrete beams, including bonding steel plates, fiber reinforced polymer sheets, and carbon fiber wrapping. Bonding steel plates was an early technique but had issues with debonding and corrosion. Fiber reinforced polymer sheets provide increased strength without corrosion risks, though delamination was also a problem. Recent techniques have focused on improving anchorage of retrofit materials to address debonding and delamination issues, with promising results in significantly increasing beam strength.