User:Adegeorge/Cornish-Windsor Bridge

The form of a covered bridge is an icon of New England. In Vermont alone, there are over one hundred covered bridges still standing. The Cornish-Windsor Bridge is an important figure of Vermont and New Hampshire. It is the longest surviving two-span wooden covered bridge in the world.



Structural Description
Builders/Engineers Bela Fletcher and James Tasker designed the bridge. The total length of the bridge is 449 feet, 5 inches. The Total width is 24 feet. The first span is 203 feet, and the second span is 204 feet. The bridge is subject to vehicular loads, and it is posted for 10 tons. Construction was complete in 1866. Since then, the bridge has been repaired at least six times in 1887, 1892, 1925, 1938, 1954-55, and 1977. Two major renovations to the bridge took place in 1989 and 2001.

The 1989 Rehabilitation
In 1989, some major improvements were made to the bridge in order for it to safely carry modern live loads. An industrial grade, prefabricated, structural glued laminated timber cords and floor beams were added to areas that experience high tensile forces. Structural engineer, David C. Fischetti, designed this rehabilitation. Solid timbers could not be used during this rehabilitation because the size and quantity required were not available as they were in 1866. It was also necessary to provide new mechanical joints and fasteners.

Qualifications as Structural Art
Efficiency/Science: The bridge is classified as a Town lattice truss. Ithiel Town patented this design in 1820. One of Town’s goals was to make the construction of this truss simple. The system is made up of smaller timbers in a dense lattice pattern. The load is not evenly distributed; therefore the structure is not as efficient with materials as it could be. The Town lattice truss is designed more for the ease of construction rather than efficiency. However, the structures permanency is estimable considering it is made of organic material.



Economy/ Social: The construction cost in 1866 was only $9000. Like most covered bridges, the structure takes advantage of locally sourced materials. This keeps the cost low. After flood damage in 1977, the state spent $25,000 in repairs. The major rehabilitation of 1989 cost $4,450,000. This was a major investment, but important for a major bridge, integral to the infrastructure of its society. Before the bridge, the Connecticut River was an obstacle to commerce. It generates a bit of tourism, meaning more business for the area. It is convenient because it is the only direct connection between VT and NH in this area.

Elegancy/Symbolism: The residents of Windsor, Cornish, and surrounding areas take pride in the bridge. It is featured on the Town Bicentennial Medal struck (1976), listed on the National Register of Historic Places, and it was named a National Historic Civil Engineering Landmark in 1970. It is the subject of many photos and paintings and it puts Windsor and Cornish on the map. The landscape of Vermont and New Hampshire wouldn’t be the same without the Cornish-Windsor Bridge.