Integrated health monitoring system for damage detection in civil structural components

This paper discusses the implementation and validation of an integrated structural health monitoring (ISHM) system on civil engineering structural components.The proposed ISHM scheme uses an emerging optical nondestructive testing (NDT) method known as digital image correlation (DIC) in parallel with established acoustic NDT techniques, including acoustic emission (AE) and guided ultrasonic waves (GUW). The proposed scheme enables the cross-correlation of in situ recorded heterogeneous NDT data, as well as loading information with progressive damage accumulation. To demonstrate the potential of the novel system, several civil structural components have been tested, such as seven wire high strength steel strands commonly used in post tensioned bridges and partially grouted concrete masonry elements. Pristine and damaged specimens have been progressively loaded to failure, while simultaneously recording DIC, GUW and AE data. The DIC results directly revealed strain accumulations at incipient failure states of strand and masonry components. Additionally, AE waveforms and related features showed sudden changes at time instances corresponding to local ruptures. Finally, GUW signals provided additional features to monitor the damage progression in the tested components. As a result, a cross-validated approach correlating full field surface based inspection with volumetric (internal) inspection was established. Current work is focused on synchronization of the different systems, detailed postprocessing of the NDT information, data filtering, alignment, and intelligent fusion. The approach presented could lead to robust damage identification strategies for SHM of civil engineering structural components.