Evaluation of Unfilled Sheath in Concrete Structures Using Response Waveform in Time Domain

Applied Sciences

Kota Ikebata¹  Yoshikazu Kobayashi¹  Katsuya Nakamura¹  Kenichi Oda¹ 

[1] Department of Civil Engineering, College of Science and Technology, Nihon University, Kanda-Surugadai 1-8-14, Chiyoda-ku, Tokyo 101-8308, Japan;

关键词: non-destructive testing;    concrete;    impact elastic wave method;    impact-echo;    difference value;    internal defects;   

DOI  :  10.3390/app112311402

来源: DOAJ

【 摘 要 】

The impact elastic wave method (IEW) has been applied to evaluate the thickness and internal defects of the target structure based on the dominant frequency of the response wave that is formed by the repeated reflections in the thickness direction. However, it is difficult to evaluate the size and position of the defect by IEW if the size and depth are relatively small and deep, respectively, and further, it is known that the technique is inapplicable if the target is not a plate-like structures. Therefore, the authors propose a new technique that uses Difference value as a new evaluation index to overcome the limitations of the conventional methods. Difference value shows the change of the response waveform in the time domain; it is computed by using a response waveform of the structures in sound condition as a reference. In this paper, the practicality of the Difference value is investigated by performing experiments using concrete specimens. The results of the experiments demonstrate that Difference value changes by the influence of internal defects, and Difference value evaluates the location of the relatively small defect that is difficult to evaluate by the conventional technique.

【 授权许可】

Unknown