Shear Strengthening Of Reinforced Concrete Beams Using CFRP Strips

Abstract

In this study, the shear strengthening of reinforced concrete (RC) beams by externally web-side bonded carbon fiber-reinforced polymer (CFRP) strips is investigated experimentally. The current study regards the problems associated with shear strengthening of RC beams without stirrups by using externally bonded CFRP strips on two opposing web sides of the beam and four ratios of longitudinal reinforcements were used as the test variables. To investigate the shear capacity of RC beams, a total of eight 130 mm x 250 mm x 2,400 mm RC beams without shear reinforcement were used. Parameters varied in the tests and included a ratio of longitudinal reinforcement (1.24%, 1.86%, 2.47%, and 3.09%) and vertical application of CFRP strips. Considering the experiment's findings, the capacity of RC beams strengthened in shear with externally bonded web-sided CFRP strips is 1.88-1.95 times greater than that of control beams. It was revealed that the longitudinal reinforcement ratio significantly influences the failure type and crack patterns in the shear span zone. With an increasing longitudinal reinforcement ratio, the shear capacity of the beam increased slightly.

Keywords

• reinforced concrete beam; carbon fiber-reinforced polymer; shear strengthening; shear capacity; diagonal cracking.