The application of a HHT based ultrasonic detecting method in quality assessment of CFST

Owed to the features of concrete and concrete pumping construction craft, empty holes, osteoporosis, construction joints and poor cementation often appear inside CFST. In view of this situation, ultrasonic detecting method has been developed to assess the quality of CFST. However, traditional methods are limited because of the effect of noise signal and distortion of signal. In this paper, the filtering process and HHT were applied to the ultrasonic signal received, and the Hilbert energy spectrum and the first-order intrinsic mode function were used to assess the quality of CFST. Actual testing results show that the HHT analysis method, combined with filtering process, can effectively improve the identification of the arrival time, the amplitude value, the waveform and the frequency of the first wave of the ultrasonic signal, and thus improve the damage identification quality of CFST.