Images created by stack imaging spectral amplitudes based on the impact-echo (SIBIE) method are largely one-dimensional because a single frequency domain spectrum for waves reflected below a single point of impact is used to create them. The method has limitations for representing defects in a cross section of a concrete structural element using two-dimensional coordinates. This study focused on defect detection and visualization in a concrete structural element using multiple impacts and accumulated SIBIE. An impactor was used to induce energy at multiple points positioned at prescribed intervals along the structural element. A modified SIBIE method was applied to the collected data for each point and the modified SIBIE images were accumulated to generate one image (an accumulated SIBIE image). As a result, the defect positions could be represented in the cross section of the structural element using a two-dimensional coordinate system. And the method appears to improve upon existing methods to detect voids or other defects in concrete.

• Lee, Sanghun(Member, Professor, Dept. of Civil and Environmental Engineering, Tohoku Gakuin University, Japan) | 이 상훈 Corresponding Author
• Endo, Takao(Professor, Dept. of Civil and Environmental Engineering, Tohoku Gakuin University, Japan) | 엔도 타까오
• Ishida, Hiroki(Professor, Kisarazu National College of Technology, Japan) | 이시다 히로키