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Modal strain identification using sub-microstrain fiber-optic Bragg grating data for damage detection of prestressed concrete structures

Book Contribution - Book Chapter Conference Contribution

© Proceedings of ISMA 2018 - International Conference on Noise and Vibration Engineering and USD 2018 - International Conference on Uncertainty in Structural Dynamics. All rights reserved. Vibration-based damage identification can constitute a successful approach for Structural Health Monitoring (SHM) of civil structures. Modal characteristics depend on the stiffness of the structure, so monitoring their evolution over time allows, in principle, to identify structural damage. Modal strains are more sensitive to local damage than natural frequencies and mode shapes, but the monitoring of these quantities is challenging due to the very small strain levels occurring during ambient, or operational excitation. Two techniques are developed for obtaining sub-microstrain measurements from fiber-optic Bragg gratings with high accuracy and precision. The ability of the modal strains to identify structural damage is explored on prestressed concrete beams subjected to progressive damage tests (PDT). Changes of the amplitude and the curvature of the modal strains are observed from an early damaged state, indicating the presence of damage even when the cracks introduced during the PDT are nearly closed due to the prestressing force, when the applied load is removed. The results indicate that a robust SHM methodology based on modal strains can be developed.
Book: Proceedings of the 28th edition of the Biennial ISMA conference on Noise and Vibration Engineering, ISMA 2018
Pages: 3605 - 3620
Publication year:2018