Development of a scanning system to detect corrosion in wire bundles and pipes, using magnetoresistive sensors

Ageing and deterioration of the main functional components of civil structures are some of the main concerns that affect their safety. In the case of relatively old suspension bridges, problems emerge due to corrosion and wire breaks in the main cables. Decisive information, reliable monitoring and evaluation, are factors of great relevance to prevent catastrophic damage to the structure and more importantly, to people. The main challenge for NDE methods of inspection arises in dealing with the signal barrier created by steel wrapping around the suspension cable. The wrapping is used to shield, shape and hold the bundles. This paper presents a scanner system based on magnetoresistive sensors that has been designed to monitor and evaluate suspension bridge cables. Modelling, signal acquisition, signal processing, experiments, on-site tests and visualisation results are presented and discussed in detail.