Optimal arrangement of AE sensors for prestressed hollow slabs based on AE propagation characteristics

Acoustic emission (AE) health monitoring is crucial for effective data collection, rational monitoring of results, and economical engineering applications in prestressed hollow slabs. To achieve an optimal sensor arrangement, experiments were performed to measure AE attenuation with different propagation paths in both the longitudinal and transverse directions of a full-scale prestressed hollow slab. Then, the AE amplitude and AE energy are chosen as evaluation indexes to investigate the hybrid arrangement of AE sensors under multiple damage conditions. The results indicate that when the AE signal propagates along the longitudinal direction of the prestressed hollow slabs with the same propagation distance, the attenuation in the steel strand is smaller. Additionally, the attenuation in the concrete directly under the bottom strand is smaller than that in the concrete between the bottom strands. The attenuation of AE propagation is smaller in the complete hinge than in the defective hinge. In terms of transverse propagation, the attenuation of AE signals is less in the bottom slab concrete than in the bottom slab steel strands. At the longitudinal 1/3 section of the prestressed hollow slab, the amplitude attenuation rate shows a turning point, and the variation in the attenuation rate of the AE signal is relatively small. For greater efficiency, it is recommended to position the sensors in the middle part of the hollow slab hinge joint and the bottom slab cross section, as well as on the concrete surface directly under the bottom slab strand.