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標題: 以自感測敲擊組件應用在混凝土淺裂縫及鋼筋保護層厚度之量測
Use of the Impactor with Sensing Device for Measuring Shallow Cracks in Concrete and the Cover Thickness
作者: 陳世賢
關鍵字: Shallow Cracks
Cover Thickness
stress wave
出版社: 土木工程學系
摘要: 非破壞檢測方法中,敲擊式應力波法共同適用於表面裂縫之深度檢測與鋼筋保護層厚度量測,為工程品質及結構安全檢測上常見之項目,且發展己相當成熟。於現行之量測方法中,若所採用之敲擊器無感測波源發生時間之功能,則需藉由第一個訊號接收器之輔助,始可反推敲擊時間原點,達到檢測之目的。應用應力波方法,量測表面裂縫之深度,與檢測鋼筋保護層厚度時,在裂縫深度與鋼筋保護層厚度的推求過程中,第一接收器對點定位產生之誤差,對於淺裂縫深度量測準確度影響最大,且由間接式反推敲擊時間原點易產生誤差,故改良敲擊器為具有自感測敲擊時間原點之功能,確實在改善檢測精度有其必要性,而且可省去第一個訊號接收器,所以同時達到為節省人力的目的。 本研究利用可感測敲擊時間原點之敲擊器,應用於一般裂縫檢測及鋼筋保護層厚度之量測,藉以驗證可感測敲擊時間原點之敲擊器之使用,能提供較佳的檢測結果。經實驗證實,應用可感測敲擊時間原點之敲擊器,確實可以提高檢測精度,同時在很淺裂縫(20mm)量測上有較佳的檢測結果。而由於其波形變化極為明顯,易於讀取對應時間,且直接得到敲擊時間原點,有利於發展自動判讀設備;而且,採用可感測敲擊時間原點之敲擊器,可以降低檢測人力與成本,又便於應用在空間不足的場所,大大提高其實務應用性及運用於現場混凝土品質檢測之可行性。
The stress wave techniques applying to measuring both shallow cracks in concrete and the cover thickness of reinforcing bars are well developed. In the current methods, because the start time of the stress waves generated by mechanical impact cannot be obtained directly, we need an additional receiver placed near the impact point to trace back the start time of impact. Thus, two receivers are needed in measurement. In the application of the stress wave method to measuring the shallow cracks in concrete and the cover thickness of reinforcing bars, the error caused by positioning the additional receiver has the most significant influence on the measurement results. Therefore, not only it is necessary to develop a sensible impactor for increasing the experimental precision, but also reduce the instrument cost as well as the manpower. The objective of this research was to verify the validity and applicability of the sensible impactor for measuring shallow cracks in concrete and the cover thickness of reinforcing bars. The experimental results show that using the sensible impactor indeed increases the precision of test. In addition, the new device provides a better result at measuring quite shallow cracks (20mm). Because the voltage-output waveform obtained from the new device is very sharp, it is easy to identify the start time of impact directly. This is favorable to develop an auto-reading apparatus. Furthermore, the cost of the experimental work and signal analysis can be reduced, and the device can be used conveniently in a relatively small space.
Appears in Collections:土木工程學系所



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