Research on the acoustic emission localisation of steel strand breakage in hollow slab bridges based on guided-waves in waveguide rods

Prestressed steel strands are one of the main load-bearing components of hollow slab bridges, and their health status directly impacts the safety of the bridge. Damage to the prestressed steel strands, especially broken wires, can lead to a decrease in the bridge’s load-bearing capacity and structural instability. This paper proposes a method for steel strand damage localisation combining waveguide rod wave propagation and acoustic emission (AE) technology. A real broken wire damage test platform was constructed with 13 slabs connected by waveguide rods. The applicability of the localisation method was studied both within a single slab and across different slabs, and the optimal parameters for various conditions were analysed and determined. The results indicate that the method, utilising a dual-sensor spatial localisation approach, can effectively locate steel strand damage in prestressed hollow slab bridges comprising 13 slabs. The study validated that the first wave arrival time difference is suitable for locating steel strands between slabs, while the maximum amplitude arrival time difference is more appropriate for locating steel strands within a slab. The study also provides guidance on selecting the appropriate localisation parameters for broken wire damage in steel strands at different locations.