臺灣博碩士論文加值系統

本研究之目的，即為利用超音波之波傳原理，及其在混凝土結構物
內部傳送的過程，使能對垂直於混凝土表面之裂縫開裂深度作一快速且精
確之判斷，以作為評估混凝土結構安全與否之依據。本論文擬採用超音波
法在檢測混凝土表面裂縫深度中，最常使用到之三種方法，即 Tc-To 法
、T 法及 BS-4408 規範所規定的方法，並提出一改良之不等距檢測法及
其計算公式。利用此四種量測方式，對已知深度之人為設計裂縫進行檢測
，將所得之結果與設計深度進行比較分析，以判斷得其試驗準確性及適用
範圍，以利在日後檢測上之應用。 由試驗之結果得知， 以本文所提出之
不等距法中，當兩探頭邊緣到邊緣之距離為14cm 到 16cm，且探頭邊緣到
裂縫的距離在 4cm 到 12cm 時，可得最佳的試驗值。

The object of the present thesis is to determine
the depths ofsurface-opening cracks in concrete structures as
soon as possible by using thebasic principle of ultrasonic
waves. In the study, there are three mostfrequently used
methods of the ultrsaonic pulse velocity methods in
thedetermination of the depths of surface-opening cracks in
concrete structures.They are the Tc-To method, the T method and
the BS-4408 method. In addition, amethod named the Unequal
Distance (U.D.) method is also proposed in thisstudy. These
four methods were used to predict the depths respectively,
usinga set of data measuring from the specimens with man-
made surface-openingcracks of known depths. By comparing the
calculated results by the formulaesof these four methods with
the prescribed depths of cracks in the specimens,we could judge
which methods would be superior to the others, and could
usethem for application. From the results of this present
thesis, the Tc-Tomethodand the U.D. method show a better
prediction than the others. Between thesetwo methods, the
results of the U.D. method is more precise than those of theTc-
To method.