Detection of Ungrouted Ducts Using the Impact-Echo Method

• Main Authors: Hsu, Yeou-Chih, 許有智
• Other Authors: Lin Yiching
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/06521423300481512242

碩士 === 國立中興大學 === 土木工程學系 === 84 === Prestressed box girders and I-shaped beams are commonly used in bridge construction. The objective of this research is to determine whether the impact-echo method is capable of detecting voids in grouted post-tensioning tendon ducts. Numerical studies were performed first to understand how the stress waves produced by point impact interact with completely or partially grouted ducts. The feasibility of using the impact-echo method for detection of voids in ducts can be evaluated. Laboratory studies were carried out to verify the numerical results. Results obtained from these studies show that there exists a big difference between the spectra obtained from impact-echo tests on completely grouted ducts and those for partially grouted ducts. The location of the ducts containing voids can be determined by identifying the corresponding high amplitude peak in the spectrum.