Recycled Plastic Forms Bridge Beams
The first all plastic vehicular bridge using unreinforced I-beams and other components made from recycled plastics is now in place in New Jersey.
The 42 foot, single lane fire equipment access bridge over the Mullica River in Wharton State Park is strong enough to support a loaded fire truck weighing 36,000 pounds.
The bridge is made from a novel composite polymer material developed at Rutgers University. Post consumer recycled polymers, such as high density polyethylene and polystyrene from consumer packaging, were used to make the tough, stiff, inexpensive structural materials, keeping these plastics out of landfills.
Neither of the constituent polymers, found in polystyrene cups and polyethylene milk jugs, would be suitable for structural use by themselves. A patented processing technology developed at the Center for Advanced Materials via Immiscible Polymer Processing (AMIPP) at Rutgers University combines the polymers to create a blended composite material with great strength.
The bridge materials started as recycled polystyrene from plastic or foam cups, and recycled polyethylene such as that found in antifreeze or milk containers.
The process melts two or more polymers together, then extrudes them to form a fine microstructure.
The special properties of the material result from the development of an oriented microstructure that gives the material unexpected mechanical properties and enables it to be used for bridge I-beams, railroad ties, boardwalk substructures and decking, and numerous other applications.
The Wharton project is the first demonstration of this new bridge building technology. The bridge was designed by McLaren Engineering, a civil engineering design and consulting firm, and consists of large I-beams supported by posts with smaller I-beams spanning between the larger structures. Three-inch thick tongue and groove decking material provides the road surface.
All bridge members are fabricated from a special formulation of polyethylene and polystyrene by the Polywood Corporation. Construction was conducted by a special engineering team headed by Professors Thomas Nosker and Richard Renfree at Rutgers University.
The new bridge, completed in November 2002, is impervious to water and weathering effects, is almost indestructible, and never needs the painting or other maintenance common to steel or wooden structures. Sunlight and other natural elements help form a thin protective coating on the surface of the polymer composite, and give it a finish that blends well with the natural surroundings.
In addition to bridge I-beams, the AMIPP Center at Rutgers is working on a variety of advanced materials using similar technologies to those used on the bridge I-beams. Included are structural materials for automotive and aerospace applications, specialized membranes and catalyst supports for the chemical process industry, and biomedical materials such as a synthetic bone material that imitates real bone when implanted in the body by promoting tissue growth through a porous polymer network. A professional race car driver and a construction equipment company have agreed to help promote wildlife refuges.
. NASCAR driver Ward Burton and his primary sponsor, Catepillar Inc., will work with the U.S. Fish and Wildlife Service (USFWS) to promote wildlife conservation and education, and to highlight the importance of the National Wildlife Refuge System, which will celebrate its 100th birthday this month.
“The National Wildlife Refuge System would not be what it is today,” said USFWS Director Steve Williams, “without dedicated partners concerned about wildlife conservation who were willing to put forth a great deal of hard work.”
Burton, a conservationist, founded the Ward Burton Wildlife Foundation in 1996, a nonprofit organization dedicated to preserving the natural environment for future generation. The foundation now owns or manages 2,100 acres.
The organization focuses on both habitat enhancement and youth education projects, such as its youth education affiliate, Return to Nature, Inc., which has reached more than 120,000 boys and girls with its conservation message.
Burton has agreed to participate in three public service announcements promoting the National Wildlife Refuge System, to display a U.S. Fish and Wildlife Service Refuge logo on his racing uniform, and serve as a refuge spokesperson during media appearances. In addition, the USFWS will continue to work with the Ward Burton Wildlife Foundation on education projects.
“Preserving our natural resources,” said Burton, “has become a passion that was instilled in me by my father and my grandfather. I believe that it is the inherent responsibility of all sportsmen and conservationists to preserve the wildlife, habitats, traditions and values we hold so dear.”
Much of the work on refuges involves habitat restoration, from stabilizing stream banks to constructing water delivery systems that sustain wetlands — work that requires the use of heavy equipment, the kind of machines made by Caterpillar.
“At Caterpillar, we’re committed to social responsibility,” says company vice president Steve Gosselin. “We’re proud of our involvement in conservation and particularly our relationship with the National Wildlife Refuge System. It has a great legacy that can be enjoyed by current and future generations.”
Provided by theEnvironmental News Service.
