Innovative Use of FRP in Large-Diameter Piles for Vessel Impact

Ferry systems in the United States in large part rely on steel pile supported structures for berthing operations. However, as ferry vessels have increased in size and environmental regulations have tightened, the use of steel for ferry landing anchor piles has become far less cost effective. As a result, ferry owners are seeking alternatives for structures designed for vessel impact. The New York City Economic Development Corporation Citywide Ferry Service recently evaluated a program of adopting composite materials for use in all new ferry landing barge anchor piles. The anchor piles hold the floating landing barge in place and are responsible for absorbing the majority of impact energy from berthing ferry boats. The program planned to use the latest fiber reinforced polymer (FRP) pile technologies, materials, and production capabilities. Dozens of steel piles would be replaced with large diameter FRP piles, with reduced lifecycle costs and ferry service disruptions. The replacement is a large diameter, thick walled FRP pile installed by driving. Though recommended after a comprehensive study of possible options, the FRP replacement was ultimately introduced to the wider project too late to be priced competitively, and conventional steel systems will therefore be installed under the current program. Nevertheless, recognition of the value added and overall cost competitiveness of large diameter FRP piles is leading the technology to be considered for additional ferry programs now in earlier stages of planning.