Flexural enhancement of natural stone beams with prefabricated prestressed CFRP-reinforced stone plates

A strengthening method employing prefabricated prestressed carbon fibre reinforced polymer (CFRP)-reinforced stone plates is introduced and assessed in this study. The primary objective is to investigate the flexural behaviour of bare stone beams reinforced with these prefabricated stone plates. A series of experiments were conducted on nine stone beams to assess their performance under varying parameters, including the prestress level of the CFRP bars and the length of the prefabricated stone plates. Strain gauges were strategically placed, and the monitoring data indicated that the prestress applied to the CFRP bars was effectively sustained after the prestressing process. Subsequent four-point bending tests revealed a distinct failure mode for the strengthened stone beams, characterised by significant deflection and the development of multiple flexural cracks. These beams exhibited a three-stage load-deflection response, demonstrating notably improved load-carrying and deformation capacities compared to their unstrengthened counterparts. A comprehensive analysis was undertaken to assess the influence of various parameters on the flexural performance of the strengthened specimens. Based on the experimental results, mathematical models were developed to predict the cracking moment, ultimate moment, and initial stiffness of the strengthened stone beams.