Strengthening stone beams with prefabricated polymer-reinforced stone plates

Abstract

A strengthening technique using prefabricated stone plates reinforced with carbon-fibre-reinforced-polymer bars is proposed to improve the flexural performance and maintain the original appearance of exposed stone beams. The effectiveness of the technique was experimentally evaluated using three stone beam specimens, considering the reinforcement ratio as the main parameter. For comparison, two specimens strengthened with near-surface-mounted (NSM) polymer bars and one bare stone specimen were also tested. The test results showed that the prefabricated plates shifted the failure mode of the stone beams from brittle fracture to more ductile behaviour manner accompanied by multiple flexural cracks. A significant increase in load-carrying and deformation capacities was observed and the flexural strength tended to increase with an increase in the polymer reinforcement ratio. No end-slip in the polymer bars was observed, indicating good bond characteristics between the prefabricated plates and the stone beams and effective composite action. Compared with specimens with NSM polymer bars, the specimens strengthened with prefabricated polymer-reinforced plates showed similar load-carrying capacity. A simplified theoretical model for predicting the flexural strength of strengthened stone beams was developed and assessed.