Assessment of an Instrumented RC Bridge with FRP Strengthening

Field instrumentation is investigated on an in-service highway bridge over a 2-year period. Extrinsic Fabry-Perot interferometric (EFPI) strain sensors provide a permanent health-monitoring capability. The bridge is a reinforced-concrete (RC) structure that was repaired and strengthened using fiber-reinforced-polymer (FRP) wraps. A sensor network monitors the load-induced strain in the FRP reinforcement and the steel rebar. Colocated electrical resistance strain gauges and a finite element analysis are used for comparison. Both dynamic and static load characteristics are analyzed for a near-capacity truck. The fiber optic measurements are generally consistent with the comparison measurements and the analytical results; and they show no failure or degradation as opposed to the electrical resistance gauges. We demonstrate the implementation and the performance of in situ EFPI sensors in a long-term field environment. Embedded fiber optic sensors can provide the required information for the intelligent management of a transportation infrastructure.