“…As nondestructive methods for SHM have become dominant in recent years, different methods have been investigated for concrete SHM such as ultrasonic [ 5 , 17 , 18 ], vibration [ 19 , 20 ], image processing [ 3 , 21 , 22 ], and acoustic emission (AE) [ 4 , 12 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. Even though ultrasonic testing can detect internal defects and their sizes, it is susceptible to complicated part geometry and certain materials, such as austenitic steel, which can mask defects by causing attenuation.…”