Inner Strength
Advanced Engineered Wood Composites
Technology used to develop hybrid wood and nonwood composite building material is at the heart of the University of Maine's Advanced Engineered Wood Composites (AEWC) Center. It all started with fiber-reinforced polymer (FRP) timbers, right. Today, the center is a world leader in the development of low-cost, high-performance composites of wood and wood by-products, natural and synthetic fibers, concrete and plastics that can be used in new products.
Patent-pending delta strand lumber developed at AEWC uses pulpwood-grade sticks to create lumber suitable for structural framing. The composite is two to three times stronger than solid wood.
In Maine from 1991–98, AEWC used fiber-reinforced polymer (FRP) wood composites to construct more than 20 demonstration bridges, ranging from 22 to 192 feet long. AEWC engineers also developed the world's longest engineered wood pier built with FRP panels, designed and fabricated on campus. The panel system delivers strength equal to concrete, but weighs 66 percent less. Civil engineering graduate student Melanie Bragdon oversaw the construction of the 167-foot Milbridge Pier, above, which opened in 2001. The pier was named America's best timber bridge in 2006 by the American Institute of Timber Construction — The Engineered Wood Association, the U.S. Forest Service and Roads & Bridges Magazine.
The U.S. Army is working in partnership with AEWC to develop a Modular Ballistic Protection System, employing lightweight composite panels that will provide troops in a tent camp environment with superior protection from mortar attacks. Two patents are pending.
Composite arches developed at AEWC can be inflated on site and filled with concrete to rapidly construct short-span bridges, hangers, tunnels and other structures. The arches are lightweight and easy to transport. Two patents are pending.
The U.S. Navy's high-speed Mark V Special Operations Craft could one day have advanced composite hulls developed by AEWC researchers to reduce shock and vibration problems now caused by the aluminum hulls. AEWC engineers are working with the Office of Naval Research and Hodgdon Yachts in East Boothbay, Maine. The research and development has already led to the creation of a new spin-off company, Maine Marine Manufacturing LLC, which infused an 83-foot-long carbon composite Mark V hull this past August. U.S. Navy photo
Composite roof systems combining framing, insulation and sheathing into a single product have the potential to be used in residential construction. The panels have been used on campus in the construction of the Child Study Center addition and the Student Innovation Center.
One of AEWC's eight patents is for an FRP composite panel, specifically designed to withstand hurricane-force winds better than conventional building materials. Currently, 15 other AEWC patents are pending.
The center is an international leader in biopolymer extrusion. This process combines fibers from sawdust or other materials (i.e. rice, flax, recycled tires) with plastics (i.e. polypropylene from recycled soda bottles) to produce the next generation of construction materials. Currently, AEWC is working with the U.S. Coast Guard to develop structural biopolymer composites that are superior in a corrosive marine environment.
By Dick Broom
November-December, 2006
