A Feasibility Study on MBN-Based Stress Evaluation of Cable-Based Bridges

This study proposes a field-scale nondestructive method for estimating the tensile stress of multiple prestressing strands in cable-based bridge systems using magnetic Barkhausen noise (MBN) sensing with an M8 electromagnetic sensor. The method targets tendon assemblies enclosed within full-size ducts, which are commonly employed in prestressed concrete, cable-stayed, and pedestrian suspension bridges. Unlike previous solenoid-based approaches limited to single strands, the M8 sensor generates a strong and uniform magnetic field through eight bar-type electromagnets, enabling simultaneous magnetization of multiple strands surrounded by protective material. MBN signals are extracted using IIR filtering and RMS evaluation, showing a consistent decrease in magnitude with increasing tensile stress. The proposed technique demonstrates feasibility as a practical, non-contact solution for tendon stress monitoring in cable-supported bridge structures.