Effect of utilizing glass fiber-reinforced polymer on flexural strengthening of RC arches

An experimental study of the flexural behavior of Reinforced-Concrete (RC) arches strengthened with Glass Fiber-Reinforced Polymer (GFRP) layers was performed. A total of 36 specimens including 3 un-strengthened (control) and 33 strengthened RC arches were tested under centrally concentrated point load. The variables of this study were steel reinforcement ratio, number of GFRP layers, and location and arrangement of GFRP layers. Failure mode, load-displacement response of specimens, crack propagation patterns, and GFRP debonding were examined. The extrados strengthening method was shown to be more effective than the intrados strengthening one in improving the failure load and rigidity of the arches. However, applying excessive GFRP layers to the extrados could change the failure mode of arches from flexural to shear. The dominant failure mode of specimens was flexural and ductile due to the formation of five-hinge mechanism. Generally, GFRP strengthening could enhance 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 in fluence of each considered parameter on the behavior of RC arches. Finally, analytical approach satisfactorily predicted the experimental data for arches with five-hinge failure mechanism.