Title: Long-gauge fibre optic sensors: performance comparison and applications

Authors: Carlos Rodrigues; Daniele Inaudi; Branko Glišić

Addresses: LABEST, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, s/n, 4200-465 Porto, Portugal ' SMARTEC, Manno, Switzerland/Roctest, St. Lambert, Canada; Via Pobiette 1, CH-6928 Manno, Switzerland ' Princeton University E330, EQuad. Princeton, NJ 08544, USA

Abstract: Long-gauge deformation sensors have opened new possibilities for the health monitoring of civil engineering structures. They are particularly suitable for applications in structures built of inhomogeneous materials, such as concrete, and with complex strain fields, such as bridges, buildings, dams, whenever the global structural behaviour assessment is of interest. Different technologies and measurement principles have been developed for measuring average strains over measurement bases that can reach tens of meters with resolutions in the micrometer range. In this work, the performances of seven commercially available alternative solutions, based on fibre Bragg-grating, Fabry-Perot interferometry, stimulated Brillouin scattering, low-coherence interferometry and traditional vibrating-wire technology, were tested and directly compared both in laboratory and in field conditions. The results are presented and discussed, aiming at the assessment of the main characteristics of each technology, and taking into account the principal requirements of in-field civil engineering applications. The efficiency of a monitoring method based on long-gauge sensors is illustrated through an application at the Ricciolo Viaduct in Switzerland.

Keywords: structural health monitoring; SHM; fibre optic sensors; FOS; long-gauge sensors; deformation sensors; performance comparison; characteristics assessment; optical fibre Bragg grating; FBG; low-coherence interferometry; Fabry-Perot interferometry; stimulated Brillouin backscattering; vibrating wire; structural engineering.

DOI: 10.1504/IJLCPE.2013.058196

International Journal of Lifecycle Performance Engineering, 2013 Vol.1 No.3, pp.209 - 233

Available online: 10 Dec 2013 *

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