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|Federal Highway Administration > Publications > Focus > March 2010 > Preserving the Past: National Historic Covered Bridge Preservation Program|
|Publication Number: FHWA-HRT-10-011
Date: March 2010
Preserving the Past: National Historic Covered Bridge Preservation Program
First constructed in 1794 in Bath, New Hampshire, the Bath Village Covered Bridge has been a continuous presence in the town ever since. When the fifth covered bridge to stand on the site was built in 1832, the town authorized signs on the wooden bridge stating, “One Dollar Fine to Drive Any Team Faster Than a Walk on This Bridge.” More than 175 years later, the 1832 bridge still displays the same message to individuals who travel over it. The 114 m long (375 ft) multispan structure, which features a unique truss and integral timber arch system that supports the roof framing, roadway deck, and sidewalk, is now being rehabilitated by the New Hampshire Department of Transportation under the Federal Highway Administration’s (FHWA) National Historic Covered Bridge Preservation (NHCBP) Program.
Established under the 1998 Transportation Equity Act for the 21st Century and continued in 2005 under the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA–LU), the NHCBP Program provides funding to States to preserve, rehabilitate, repair, or relocate historic covered bridges. SAFETEA–LU authorized $10 million annually to be appropriated between fiscal years 2006 and 2009, with future funding awaiting reauthorization of SAFETEA–LU. To qualify for funding, a covered bridge must be listed or eligible for listing on the National Register of Historic Places. Program grants require that to the maximum extent practicable, the project is carried out in the most historically appropriate manner, preserves the existing structure of the historic covered bridge, and provides for the replacement of a bridge's wooden components with new wooden components, unless the use of wood presents safety concerns.
"The program has been very well received," says Everett Matias of FHWA's Office of Bridge Technology. "Many of the bridges have a story to them and communities feel strongly about preserving them." The size and scope of the funded projects range from smaller scale initiatives such as installing fire protection and security systems to complete rehabilitation efforts.
The rehabilitation of the Bath Village Bridge is slated to begin in 2010. Broken, rotted, and damaged bridge members will be replaced, along with the roof and floor systems, and the bridge's fire protection system will be improved. The FHWA funds will cover 80 percent of the estimated $2.3 million cost. This rehabilitation work will preserve one of the oldest wooden covered bridges in the United States and enhance the local historic district, as well as continue to provide a critical crossing of the Ammonoosuc River for police and fire department emergency vehicles.
Also being rehabilitated under the program is the Hutchins Covered Bridge in the Town of Montgomery, Vermont. Montgomery has the highest concentration of covered bridges in the State. All of the bridges were built by two brothers, Savannah and Sheldon Jewett, who prepared the timber for the bridges at their own mill. Constructed in 1883, the Hutchins bridge consists of a single span supported by two flanking timber Town lattice trusses. The bridge rests on abutments built of irregular stone blocks, which stand on prominent outcrops of bedrock.
The $1.2 million rehabilitation project includes replacing the floor system, decking, and various rotten and damaged members, as well as repairing the lateral bracing, siding, masonry, and concrete abutments.
A smaller scale project in Troy, Vermont, will rehabilitate the 1910 River Road Covered Bridge across the Missisquoi River. The only covered wooden bridge remaining in Troy, the bridge has a unique design, including Town lattice trusses supported by three chords instead of the usual four chords, a steep–pitch gable roof with wide overhangs, and three exterior timber buttresses. The $250,000 project is designed to ensure continued use of the bridge for light traffic. Improvements to be made include roof, timber, and abutment repairs.
In Lincoln County, Oregon, the $665,000 rehabilitation of the Yachats Covered Bridge, built in 1938, will include installing new hangar rods, siding, and timber decking, as well as painting, possible roofing work, and construction of steel–backed timber railing. The project is currently in the initial stages. As Oregon noted in its project application, covered bridges are an important contributor to tourism in the State. The rehabilitation work will contribute to the local economy by preserving a significant and popular historical structure.
Smaller projects funded by the NHCBP Program, meanwhile, include Union County, Ohio's, 2007 award for the installation of lighting and smoke detection systems on four covered bridges in the county. The new systems are helping to protect the bridges while not detracting from their visual and historical significance.
About 10 percent of the NHCBP Program funding is set aside for research and technology transfer. FHWA is collaborating with the National Park Service (NPS) and U.S. Forest Service to conduct more than 22 projects. These projects include Covered Bridge Rating Through Load Testing, which will develop recommended procedures for load rating historic covered bridges through physical testing, and Improved Analytical Techniques for Historic Covered Bridges, which will develop guidelines for improving the analysis of covered bridges. Specific areas of interest for analysis include the intersection and interconnection of lattice members, behavior and interaction of bolster beams, and the influence of bracing.
Technology transfer activities include developing A Wood Preservative Treatment Guide for Historic Covered Bridges and Standards for the Treatment of Historic Covered Bridges with Illustrated Guidelines for Preserving, Rehabilitating, Restoring, and Reconstructing Historic Bridges, which will provide needed guidelines reflecting current best practices in historic preservation.
For more information on the NHCBP Program, visit www.fhwa.dot.gov/bridge/covered.cfm, or contact Everett Matias at FHWA, 202–366–6712 (email: firstname.lastname@example.org). To learn more about FHWA's historic covered bridge research and technology transfer activities, contact Sheila Rimal Duwadi at FHWA, 202–493–3106 (email: email@example.com).
United States Department of Transportation - Federal Highway Administration