Health monitoring of fiber reinforced polymer bridge decks with infrared thermography

Over 41% of the bridges in the United States are structurally deficient or functionally obsolete. As this infrastructure continues to age, the funding necessary to remedy this crisis will soar. Due to the inadequacy of capital allocated for infrastructure repair and rehabilitation, new types of potentially more durable bridges with longer service lives are being explored as a means of narrowing the financial deficit. One solution being investigated is the use of fiber reinforced polymers as a replacement for bridge superstructure components historically constructed with conventional structural materials (such as reinforced concrete and steel). A fiber reinforced polymer has a much higher strength to weight ratio than conventional materials and is thought to be less reactive with environmental and conditional corrosives, such as alkalines and deicing salts. In order to expedite acceptance of fiber reinforced polymers into common use for bridge construction, a means of reliably testing and monitoring the health of fiber reinforced polymer components should be developed and standardized. One of the most promising methods for health monitoring of fiber reinforced polymer bridge components (specifically bridge decks) is the use of infrared thermography. A slight elevation in temperature (a few degrees above ambient radiant energy) will allow for adequate detection of debonding between fiber reinforced polymer components. This paper will explore the preliminary use of infrared thermography, with verification by acoustoultrasonics, in laboratory and field health monitoring of several glass fiber reinforced polymer bridge decks, specifically for debonding between integral components.