Flexural Performance of Stone Beams Strengthened with Prefabricated Prestressed CFRP-Reinforced Stone Plates

Abstract

A strengthening technique incorporating prefabricated prestressed carbon fiber–reinforced polymer (CFRP) was proposed and evaluated. The flexural performance of bare stone beams strengthened with prefabricated prestressed CFRP-reinforced stone plates was investigated by testing 11 stone beams. The test variables considered involved the diameter and prestress level of the CFRP bars, the reinforcement ratio, and the surface condition of the stone plate. The stress transfer efficiency between different components during the prestressing and strengthening processes was monitored with the aid of strain gauges that were attached to the CFRP bars and stone beams. The monitoring results showed that the CFRP bars prestress could be effectively maintained by the temporary device and then transferred to the stone beam to be strengthened. Further four-point bending tests indicated that the strengthened stone beams exhibited a failure mode with obvious deflection and multiple flexural cracks. The strengthened beams presented three stages of load versus deformation responses and showed significantly higher load-carrying and deformation capacities than the bare stone beams. The flexural behavior of the strengthened stone beams for different parameters was analyzed. Finally, models were proposed to calculate the cracking and ultimate moments, and the initial stiffness of the strengthened stone beams.