Non-destructive evaluation of micro-damage near concrete anchors under dynamic loading

Abstract

Assessing the condition of concrete near anchors is essential, as potential cracking can reduce the stiffness and strength of fastening capacity. This study developed a novel concept with non-destructive testing methods to evaluate micro-damage in concrete near anchors. A mechanical wave energy method was proposed to detect non-visible, micro-scale damage in concrete, which has been challenging to assess using conventional NDT techniques. A unique contactless testing system was designed to capture ultrasonic waves without coupling issues, and the energy of these waves was analyzed in the frequency-wave number domain. Validation was conducted through both numerical and experimental approaches, where five specimens were subjected to various external loads to induce real cracks. The results demonstrated that this method enables quantitative evaluation and localization of non-visible, micro-scale concrete damage near the anchor, even when structural behavior is minimally affected.