Damage progression in RC beam‐column joints under cyclic loading using acoustic emission technique

Abstract

AbstractBeam‐column joint (BCJ) is the most critical element of a RC structure and plays an important role in the sound seismic performance of buildings. A number of joint failures have been reported in the literature and it is important to monitor the BCJ regularly to assess their performance so that the damage is predicted much before it reaches a catastrophic level. This study aims to monitor the initiation and progression of damage in BCJ reinforced with and without ductile reinforcement detailing under cyclic loading using a real‐time passive acoustic emission (AE) technique. Results have been analyzed on the basis of AE parameters such as cumulative AE hits, cumulative energy, rise angle, average frequency, and Ib‐value. The Ib‐value analysis has demonstrated good correlation with the experimental observations and it has been established that macroscopic fracture occurs in a RC BCJ during loading. The AE event map successfully gives pictorial representation of the crack development inside the concrete and crack pattern plotted by the AE event maps gives an idea of presence of cracks near the damage area of BCJ. It is also possible to distinguish between tensile and shear crack developing at the joint by using AE data. A linear relationship has been observed between the AE energy and energy dissipated by BCJ to evaluate damage indices in seismically damaged structures. The AE energy gives better representation of quantum of damage than AE hits.