Strain and deformation monitoring in infrastructure using embedded smart FRP reinforcements

Smart glass fiber-reinforced polymer (GFRP) rods are used in conjunction with steel rebars (collectively, hybrid reinforcements) to reinforce two concrete beams. The GFRP rebars are fabricated using a modified pultrusion process, which allows both the embedment of Fabry-Perot fiber-optic sensors (FP-FOS) within the composites, and the successful recovery of the associated fiber-optic leads. The beams are subjected to static and repeated loads to failure. The strain state and deflections of the beams during loading are monitored by the embedded sensors as well as by electrical strain gages (ESG's) and LVDT's. The accuracy of the strain readings from the FP-FOS is verified by comparison with the corresponding readings from the ESG's. Collectively, the experimental analysis shows that the GFRP rebars can be employed with their steel counterparts to successfully reinforce concrete. These GFRP rebars can fulfill a dual role; reinforcing elements by virtue of their mechanical properties and long-term strain monitoring devices by virtue of the embedded sensors.