Cracking mechanisms of diagonal-shear failure monitored and identified by AE-SiGMA analysis

The maintenance of concrete structures has become a serious problem, because concrete is to be realized as no longer maintenance-free. Recently, diagonal shear failure of concrete structures draws a great attention because of disastrous damages due to earthquakes. Accordingly, structural monitoring and assessment of failure or damage by nondestructive evaluation (NDE) is in remarkable demand. Acoustic emission (AE) is known to be promising for NDE of concrete structures for diagnostics and health monitoring. It is known that fracture mechanisms are identified by AE wave form analysis. As a quantitative waveform analysis of AE signals, SiGMA (simplified Green’s functions for moment tensor analysis) procedure has been developed. Based on the moment tensor analysis, crack location, crack type and crack orientation are readily identified. In the present study, diagonal shear failure in reinforced concrete (RC) beams is investigated, applying the SiGMA analysis. Thus, cracking mechanisms are clarified and an application to structural monitoring is discussed.