Discussion of Fiber Bragg Grating Technology Applicability on Diagnostic Field Testing of Steel Girder Bridges

The application of Fiber Bragg Grating (FBG) technology for purposes of diagnostic field testing on steel girder bridges is discussed in this paper based on the authors experience in field tests of highway bridges. The primary benefit of the FBG technology is the ability to have many sensors (strain gages) multiplexed in a single fiber optic line. In practice, the FBG system is problematic for field conditions of a typical highway bridge. In field tests, measured FBG data showed that the strain histories obtained for a load immediately above the girder of interest were accurate, but the accuracy of the strain histories decreases for adjacent girders as the transverse distance from the load increased. Moreover, protective measures are necessary for FBG systems to be utilized in highway bridge field testing.

Keywords: Diagnostic bridge field testing; Fiber optics technology; Strain gages