World’s First Thermoplastic Bridges

Deterioration of bridges in the United States has been well recognized. According to the FHWA National Bridge Inventory, one third of nearly 600,000 U.S. highway bridges are classified as structurally deficient or functionally obsolete. Since the majority of bridges were built using wood, steel or concrete, the same conventional materials have been used for bridge replacement or rehabilitation, imposing similar patterns for future deterioration. However to address recent emphasis on durability, accelerated construction and sustainability, including “Going Green,” new advanced materials are coming on the market. Developed in conjunction with scientists at Rutgers University, a manufacturing company named Axion International, Inc. was able to produce a thermoplastic composite material made of nearly 100% recycled post consumer and industrial plastics that would otherwise be discarded into landfills. This environmentally friendly thermoplastic was first utilized for railroad crossties and recently extended its application to bridge and structural members. In early 2009, the first bridges in the world made of recycled plastics capable of carrying a 71-ton tank and HS25 loads were built at Fort Bragg, North Carolina. Virtually all bridge components, including girders, pier caps, decking, railings and pilings, are made from recycled plastics. The bridges were designed for HS25 and the 71-ton M1 Abrams Tank. Impressed by these developments, Fort Eustis in Virginia also decided to utilize the material to replace two aged railroad timber bridges. The world’s first railroad bridges made from this innovative and sustainable material with total lengths of 38.5 feet and 84 feet are being designed to carry a Cooper E-60 and a 260 kips alternate load; they are scheduled to open in June 2010. A detailed design process and discussion on this cost-effective and environmentally superior solution will be presented in this paper.