Corrosion or other types of degradation caused by aging, etc. under environmental influences, poor routine
maintenance leads to deterioration of concrete structures, which required repairing of these structures. In addition,
structures, which needs to increase load carrying capacity because of changing usage, or considering some of
design and construction defects due to poor quality control, must strengthened. So studying the effect of different
methods of strengthening is very important. Using of fiber-reinforced polymers (FRP) is one of the more widely
accepted methods for strengthening and repairing of reinforced concrete (RC) and prestressed concrete structural
elements. FRP had a number of benefit characteristic such as lightweight due to low density, easy handling, high
strength, high stiffness and high corrosion resistance, which make it durability and require less maintenance.