Evaluation of reinforcement in damaged railway concrete piers by means of acoustic emission

We focus on a particular case of concrete piers, in which the damaged state and repaired state can both be investigated. In order to know the precise damage condition within the piers, boreholes are excavated, followed by internal wall observation with a borehole camera. Cracks within the retrieved core samples are examined with impregnation of fluorescent epoxy. In AE monitoring, active loads with train passage are utilized to induce AE signals. AE sources are only extracted from the detected raw AE data set using 3D source location. On the basis of the extracted AE events only, the damage quantification is performed along with an analysis of AE peak amplitude distribution. The AE monitoring is additionally performed in the structure after repair works have been completed, and the repair work is evaluated with AE activity. Through the AE monitoring in comparison with several observation techniques, it is concluded that the degree of damage can be quantified with the AE amplitude distribution reasonably well and the effectiveness of repair works can be evaluated with the distribution.