Enhancing beam performance using ınternally bonded carbon fiber-reinforced polymer

The load-bearing capacity of structural elements can be significantly increased by externally reinforcing them with carbon fiber-reinforced polymer (CFRP)-bonded epoxy. Typically, FRP strips are wrapped around bars to reinforce the interior of beams. In this study, the beams were strengthened using alternative configurations to increase their load-bearing capacity and the failure modes were analyzed. The beams were reinforced by covering them with FRP using epoxy, one of which was weak in bending but strong in shear. Different reinforcement configurations were used in the stirrups and tension zone bars depending on the weakness of the beams. The strategic placement of the reinforcing bars within the beams facilitated the examination of the bearing capacity and failure mechanisms. The beams were fabricated using laboratory-made concrete with a strength of 23 MPa; the bars were assembled accordingly. The results of the four-point bending tests revealed that the stirrups reinforced from the sides of the beam increased its strength by 26.8% compared with that of the reference beam. The bearing capacity of the FRP strips wrapped on the stirrups significantly increased, whereas that of the strips wrapped on the steel bars in the tension zone decreased or remained unchanged.