3D ‐Damage monitoring of RC beams strengthened with CFRP sheets by full‐waveform AE technology

Full‐waveform acoustic emission (FWAE) technique is known to be an appropriate method for detecting active and passive damage nondestructively in concrete structures. In order to evaluate the bending mechanical behavior of reinforced concrete beams reinforced with CFRP sheets, as well as to detect damage accumulation and assess the evolution of AE signals, four‐point bending static loading tests were performed on three reinforced concrete beams with and without reinforcement, using the DS5‐FWAE monitoring system. The findings demonstrate that the CFRP sheets boosted the reinforced concrete (RC) beam's ultimate load bearing capacity in the positive section by 61.3%, while the CFRP‐bonded efficiently stopped crack growth and improved the mechanical characteristics of the damaged beam. The FWAE parameters were used to monitor the ongoing damage process on the RC beams strengthened with CFRP sheets, assess damage degree, and estimate damage location. As a result, a 3D dot‐matrix AE source locating monitoring approach for the damage process of strengthened‐CFRP RC beams, including crack initiation and propagation, was developed and validated using DS5‐FWAE tests. The findings demonstrated that the devised approach can assess the damage process, quantify the damage degree, and predict the damage region of failure beams under graded load. The damage full‐process was classified into five stages based on waveform characterization: healthy (0), minimal damage (I), moderate damage (II), severe damage (III), and failure (IV). Eventually revealed, the proposed 3D damage monitoring methodology was more feasible and practical in monitoring damage process, determining damage level and estimating damage region. This has opened up new possibilities for real‐time monitoring of the damage process, determining damage extent, and identifying damage regions for CFRP‐strengthened RC beams under complicated loads.