effect of utilizing glass fiber-reinforced polymer on flexural strengthening of rc arches

An experimental study on the flexural behavior of reinforced concrete (rc) arches strengthened with glass fiberreinforced polymer (gfrp) layers is performed. totally, 36 specimens including 3 unstrengthened (control) and 33 strengthened rc arches were tested under centrally concentrated point load. the variables of this study were the steel reinforcement ratios, number of gfrp layers, and location and arrangement of gfrp layers. the failure mode, loaddisplacement response of specimens, crack propagation patterns, and gfrp debonding were examined. the extrados strengthening method was more effective than intrados strengthening approach in improving the failure load and rigidity of the arches. however, applying excessive gfrp layers at extrados can change the failure mode of arches from flexural to shear failure. the dominant failure mode of specimens was flexural and ductile failure due to the formation of fivehinge mechanism. generally, gfrp strengthening could augment the ultimate load carrying capacity, secant stiffness, and energy absorption capacity of arch specimens by up to about 154, 300, and 93 percent, respectively. statistical analyses were performed to assess the level of influence of each considered parameters on the behavior of rc arches. finally, analytical approach predicts the experimental data on arches with fivehinge failure mechanism satisfactorily.