Demonstration of Fiber Optic Instrumentation System for Prestressed Concrete Bridge Elements

Structural health monitoring (SHM) is a relatively recent approach to managing and extending the useful life of bridge infrastructure elements. To be useful, SHM techniques must be robust, rapidly deployable, and yield information useful to those rating the structures. Fiber optic–based sensors have been used in this regard but on a relatively limited basis in North America. Fiber optic sensors have many advantages over more conventional structural monitoring sensors, and their utility has been well established. While verification of SHM-generated data with other instrumentation schemes is important, validation using simple analytic tools is critical because such tools are the basis for most bridge rating and management systems. In this paper, load testing of a decommissioned prestressed adjacent box girder is presented. The objective of the test was to demonstrate a proof of concept for a fiber optic–based instrumentation system for bridge monitoring. Fiber optic–generated measures of girder performance are compared with other experimental test data and a relatively simple but robust analytic model of the girder. The tested fiber optic system demonstrated excellent performance, and data recovered correlated well with a well-established analytical modeling technique, thereby demonstrating the immediate utility of the fiber optic system.