Abstract
A significant opportunity exists in the United States to improve local transportation networks and to assist in revitalizing local economies by using wood for bridges and other transportation structures. Modern timber bridge technology provides an opportunity to improve transportation infrastructure, particularly bridges on single- and double-lane rural roads. To address this issue, the U.S. Congress provided funding to the U.S. Department of Agriculture’s Forest Service in 1989 for a program called Wood in Transportation (WIT), formerly known as the National Timber Bridge Initiative. The program has three key components: (a) demonstration projects, (b) research, and (c) technology transfer and information management. The current focus of the demonstration projects is on funding approximately four large-scale “commercialization” projects per year that result in the construction of three or more structures. The intended outcome of these projects is to develop structures that showcase WIT technology and provide useful design and cost information to potential users throughout the nation. These projects build on past knowledge gained from research and other previously funded projects. The successful completion of three commercialization projects is highlighted. The first one was in Yellowstone County, Montana, where three glued-laminated timber bridges were designed, fabricated, and installed in 1998. The second project was in Ida County, Iowa, where five cotton-wood glued-laminated deck bridges, supported by either steel beams or glued-laminated beams, were designed, fabricated, and installed in 1999. The third project was in West Virginia, where nine timber decks with steel-beam bridges were constructed on “orphan roads” in 1999.
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