An Innovative Health-Monitoring Approach for Fiber-Reinforced Polymer Debonding Diagnosis Through Pullout and Shear Tests

The need for rehabilitation of Reinforced Concrete (RC) structures is highlighted by the increased requirements for adequate resistance to seismic actions. Recently, a novel Fiber Reinforced Polymer (FRP) -based strengthening approach utilizing FRP ropes has been introduced. The application of this new technique seems to have promising results when the ropes are anchored adequately. However, constructional restrictions may prevent the adequate FRP rope anchorage and lead eventually to the failure of the strengthening application. This study uses an innovative remotely controlled Electro-Mechanical Admittance (EMA) based SHM system to detect the structural damages that occurred in FRP-strengthened RC members due to the composite rope failure. The SHM approach employs custom-made devices that excite a network of intelligent Piezoelectric lead Zirconate Titanate (PZT) transducers/actuators by means of an amplified harmonic excitation voltage. Two test procedures are presented to verify the proposed SHM systems experimentally, including pullout tests of FRP ropes with different anchorage configurations and a large-scale shear-critical RC beam with a T-shaped cross-section. The installed PZT transducers showed promising damage indications demonstrating a direct correlation with the mechanical performance of FRF rope, composing an emerging tool for real-time identification of FRP failures.