Signal processing procedure for non-destructive test of concrete structure integrity

A signal processing procedure is proposed for testing concrete integrity using impact by shock wave and Laser Doppler velocimetry. The concrete surface vibration signal is first segmented into successive frames. The signal in each frame is analyzed using a linear prediction model to calculate the normalized prediction error. This error indicates the degree to which the signal is modeled in the form of an exponentially decaying sinusoid, and the presence of sub-surface flaws in the concrete can be determined from its value. When a defect in the concrete is detected, the frequency of the decaying sinusoid is calculated to estimate the depth and size of the crack. The proposed procedure was applied to computer-generated signals and actual vibration signals produced by shock waves, and the success of the procedure was verified.