Damage characteristics and assessment of corroded RC beam-column joint under cyclic loading based on acoustic emission monitoring

Corrosion of reinforcements is a potential threat to reinforced concrete (RC) structures, especially in terms of their seismic performance. In this study, the damage characteristics of corroded RC beam-column joints under lateral cyclic loading were inspected by Acoustic Emission (AE) technique. It was found that AE technique was also effective for monitoring and assessing the damage of corroded RC structures. AE hits analysis and amplitude analysis were conducted to expose the crack development process and the potential damage pattern. Both analysis results demonstrated a good correlation with the experimental observation. Based on the b-value analysis, the magnitude variation of the cracks along with the lateral loading process was then examined. Besides, AE intensity analysis revealed that there was a good correlation between peak value of history index and the drift ratio of maximum capacity reached for corroded joints. Accumulative AE energy revealed a good correlation with accumulative hysteretic energy and based on that, damage level prediction equations for corroded joints were proposed.