Repair and Strengthening of Submerged Steel Piles Using GFRP Composites

Steel and concrete bridge structures that serve as the backbone of U.S. transportation and navigational infrastructure systems have been exhibiting moderate to severe deterioration within a few years of service. The focus of this paper is on the rehabilitation of water-submerged bridge steel piles using precured glass-fiber-reinforced polymer (GFRP) shells wrapped with water-curable GFRP prepreg fabrics. The GFRP shells were placed around the corroded steel piles of the East Lynn Lake Campground Bridge in Wayne County, West Virginia, and wrapped with GFRP fabrics. The space between GFRP shells and steel piles was filled with self-consolidating concrete to strengthen and protect the piles from further deterioration. Prior to field implementation, experiments were conducted on concrete cylinders embedded with steel I-sections that were encased by a polymeric shell and FRP wrap system to evaluate the load transfer mechanisms and increase in concrete strength as a result of confinement. To increase the load transfer between embedded steel and concrete, steel rods and angles were welded to the steel I-sections, which resulted in a 92% or higher degree of compositeness. Using the GFRP shell and wrap system, the bridge was restored to its design capacity at approximately 10-15% of its replacement cost.