Beam-column joints are the crucial zones in reinforced concrete (RC) structures as they are subjected to large forces during earthquakes and their behaviour has a significant effect on the response of the whole structure. When the shear capacity of a joint is insufficient, the structure may fail in a brittle behaviour due to large amount of shear stress concentrations in this region. Thus, strengthening of deficient RC beam-column joints is important. In most cases, the strengthening material covers the structure and it is not possible to see any damage on the surface when the joint is subjected to a force. Acoustic Emission (AE) is a useful method to detect crack development and progress in concrete non-destructively. Location of the fracture source in a material, the size and energy of the crack and the time it starts cracking can be identified by AE method. In this study, identification of fracture mechanisms of strengthened RC beam-column joints was aimed. For this purpose, the specimens were tested under cyclic loading and monitored by AE. Afterwards, obtained AE data of the specimens were analyzed and they were compared with the mechanical results.

beam-column joint, acoustic emission, parameter analysis, crack localization analysis, fracture mechanism