2017 Volume 66 Issue 9 Pages 443-450
This paper describes the non-destructive inspection method to detect a void inside the PC grout by using an impulse hammer and accelerometers. We have already proposed the non-destructive inspection method to detect a crack inside a large concrete structure such as a caisson by using an impulse hammer. The proposed method can detect a crack deep inside a large concrete structure because of using low-frequency vibration signals, which are generated by the impulse hammer. Moreover, this method can also use the impulse hammer’s output signal as well as the accelerometers output signal. Therefore, the proposed method can estimate the position and size of a crack by the beam forming method. In this paper, we describe the application of the proposed non-destructive inspection method using an impulse hammer to detect a void inside the PC grout, and we evaluated the proposed application method. To evaluate the performance of the proposed method, we experimented using specimens of a PC-bridge. Moreover, we analyzed the propagation of the impact wave in specimens by FDTD method. From the results of the experiment and analysis of impact elastic wave propagation, we realized that the proposed method could measure the influence of a void inside the PC grout.
