Towards Acousto-Ultrasonic Inspection of Cables Within Their Anchor Bases for Suspension Bridges

This study proposes an approach based on an acousto-ultrasonic method and feature-based analysis to assess the condition of cables within their anchor bases. Experimental tests were performed on several model anchor configurations, including a healthy reference (REF-1) and different degraded configurations (namely DEF-1Z, DEF-2Z, DEF-W), in order to investigate the influence of the number of broken wires on the recorded signal. The acquired signals were characterised using acoustic emission features such as amplitude, energy, duration, counts, and centroid frequency. Z-score normalisation was applied according to two strategies—joint normalisation using a reference anchor base, and reference-free normalisation—in order to better reflect in situ inspection conditions. The objective is to discriminate between healthy and degraded cable states within anchor bases, first with a reference-based approach and then without any reference. The results show that several features have strong discriminative potential. In addition, the reference-free results show good agreement between sensor positions and degraded areas, confirming the localisation of the damage. Overall, this approach appears promising for future in situ applications.