Demonstration and Validation of a Lightweight Composite Bridge Deck Technology as an Alternative to Reinforced Concrete

Abstract : Cyclic loading and weathering of reinforced concrete bridge decks cause corrosion of reinforcement steel, which leads to cracking, potholes, and other problems. This project demonstrated the use of a glass-fiber reinforced polymer (GFRP) composite deck system, which does not use any reinforcement steel, on a deteriorated concrete bridge at Redstone Arsenal, AL. A pultruded deck system made by Zellcomp, Inc., was selected for demonstration and validation. The demonstrated system was designed to retain the 36-ton (HS-20) load rating of the original bridge. This report documents demolition of the existing deck, installation of the composite deck system, materials and load testing, remediation of initial problems, and an economic analysis in terms of return on investment (ROI).The main problems identified after construction were reflective cracking of the polymer-concrete wear surface applied over the composite deck sections; and gaps and voids related to grout forms and supports installed between bridge girders and deck sections. After repairs, the bridge was returned to service and is functioning normally. The calculated ROI for this technology was5.4. Although there are not yet consensus standards for composite bridge decks, the demonstrated technology can be effectively applied using existing load-resistance design factors and manufacturer installation instructions.