| Summary: | 碩士 === 國立成功大學 === 土木工程學系 === 103 === The non-destructive test (NDT) of pile without pile cap had been well developed, and considerable results had been shown. In the case of pile with pile cap, on the other hand, because of its geometry and pile cap boundary effects, complicated the testing results. Therefore, more research has to be done in the NDT of pile with pile cap.
This study applied the modified Hilbert-Huang transform program on NDT of piles with pile cap in hope to separate the pile cap, defects, and pile bottom signal to estimate the location of them. Impulse response method was chosen for this study, and the effect of using different types of impact hammers and frequency range was discussed. The effect of sensor locations was also discussed in this study. The results showed that the impact hammer that excites higher energy should accompany with higher sampling frequency band, and vice versa. The sensor location had no effect on testing results. Except for the intact pile, the frequency-time analysis results of all other defect piles were not acceptable with the problem of mode mixing, and it shows that the existence of pile cap present a big problem in analyzing the data. The testing result of the intact pile was further analyzed with modified Hilbert-Huang transform. The results showed that although mode mixing problem was reduced, the analyzing result looks no different than the original result.
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