A field deployable, multiplexed Bragg grating sensor system used in an extensive highway bridge monitoring evaluation tests

Abstract

A multiplexed optical fiber Bragg grating sensor system with a measurement bandwidth of up to 200 Hz enabling dynamic loading events, e.g., road traffic, to be observed has been designed, installed, and tested over an 18-month period on a 346-m road bridge in Norway, for design verification and structural integrity monitoring purposes. A network of 32 fiber Bragg sensors was surface bonded along with a corresponding set of resistive strain gauges for comparative tests to be made. The wavelength data were calibrated against two thermally stabilized ( 0.15 pm) reference gratings, which rejected common mode noise and provided absolute wavelength scaling. These data provides independent strain and temperature information. Long-term test results showed good linearity and repeatability of 10 over the test period with a precision of 5 and a resolution of 1 . The readings from the FBG sensors were comparable to those from the foil gauge sensors to within 4 .

Development of a Bridge Weigh-in-Motion Sensor: Performance Comparison Using Fiber Optic and Electric Resistance Strain Sensor Systems

“…Previous work on the use of Fibre Bragg Grating sensors for strain measurement has been extensively documented in the literature, e.g. [9], [10]and such sensors have been developed for measuring rapid, dynamic changes and long-term performance of concrete bridges and composite steel-concrete box structures [11]- [13]but this packaged FBG technology has not been used for sub microstrain measurements needed for accurate Bridge Weigh-in Motion under dynamic moving loads.…”

Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

“…In this tests carried out, one of the available 8 channels from the optoelectronic interrogation system discussed previously (based on WDM technology) is used [8]. This incorporates a 20 mW 1520-1560 nm broadband light source, a Fabry-Perot spectrometer, an eight-way optical fiber splitter, an eight PIN photodiode detectors, an eight-analogue channel digital sampling processor DSP (AdwinGold), and is connected to the computer via the USB port for data storage, analysis, and transfer.…”

Commissioning and Evaluation of a Fiber-Optic Sensor System for Bridge Monitoring

“…The use of fiber optic strain sensors for structural health monitoring is not, of course, new and considerable work has been published by some of the authors and others for work done under a range of field applications [1]- [15] over a considerable period. This paper was different in that, in cooperation with the owner of the bridge, specific loading tests were planned and carried out during a closure of the structure.…”

“…bare fiber) Fiber Bragg Grating (FBG)-based sensors as had been used in previous work on actual bridges by some of the authors [1], [2] as they were more liable to breakage and the strain transfer ratio was more difficult to evaluate in the short time that the bridge was available to the experimenters. Thus commercially available fiber optic strain sensors were chosen for this application.…”