Acoustic Emission-Based Structural Evaluation of RC Beams with and without FRP Strengthening Under Monotonic Loading

This study investigates the structural behavior of reinforced concrete beams using acoustic emission (AE) monitoring. This non-destructive test detects ultrasonic elastic waves generated by sudden energy release during microstructural changes. The research focuses on two beam specimens subjected to monotonic loading: an unstrengthened beam and a beam retrofitted with carbon fiber-reinforced polymer (CFRP) strips using the Externally Bonded Reinforcement (EBR) technique. Piezoelectric sensors captured AE signals associated with crack propagation, plastic deformation, and bond rupture, enabling real-time damage assessment. The CFRP-strengthened beam exhibited reduced ultimate deflection due to the composite material's limited ductility, while demonstrating distinct AE characteristics during failure. Notably, interfacial debonding and sudden CFRP strip separation produced significant AE signal variations. Comparative analysis revealed that while the strengthened beam developed fewer and narrower cracks, it released substantially higher AE energy within a shorter duration compared to the control beam. This contrasting behavior highlights the complex energy dissipation mechanisms in FRP-strengthened concrete members. These findings demonstrate AE monitoring's effectiveness in characterizing failure modes and damage progression in reinforced concrete structures. The identified signal patterns provide critical insights for developing reliable structural health monitoring systems, particularly for structures with external FRP reinforcement. The study contributes to improved understanding of failure mechanisms in retrofitted concrete members through advanced sensor-based evaluation.

کلیدواژه ها:

Acoustic emission (AE) ، Structural health monitoring (SHM) ، Non-destructive testing (NDT) ، Strengthening of concrete structures ، Fiber reinforced polymer (FRP) ، Monotonic loading