Abstract
Ageing of infrastructures is an un-avoidable issue. To sustain those as long as possible even with reasonable budgets, proper investigations giving quantitative evaluation of soundness should be carried out at appropriate timing. Acoustic emission among NDT techniques seems quite useful to monitor the global integrity of civil structures since one sensor covers a wider range than other techniques and only damage-related cracks/defects induce the AE activity. In the paper, several damage indices obtained from AE parameters are introduced and such applications as for materials characterization and for in-situ structural evaluation are discussed. Through the applications, it is concluded that AE monitoring has potential to be a crucial monitoring technique contributing to expand the service life of civil structures.
