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Open Timber Truss

Vermont's earliest bridges were simple, open timber trusses, the technology for which was likely brought over by the first European settlers. In 1785, Enoch Hale, a builder from Rowley, Massachusetts, constructed one of the country's first timber frame bridges across the Connecticut River between Walpole, New Hampshire, and Bellows Falls, Vermont. From the 18th century through the early 20th century, timber frame bridges populated Vermont's rural roads. Many, however, have been replaced or were lost during the 1927 flood. Two truss types were dominant in timber bridge construction: king post and queen post.

The king post truss, consisting of one vertical post at the center of a triangle, was primarily suitable for spans less than 50 feet. Multiple king post trusses allowed a longer span. A single king post is seen in the image on the left, while a multiple king post is seen on the right.

King Post Truss King Post Truss

King Post Trusses: Image courtesy of Robert McCullough, Crossings: A History of Vermont Bridges, 2005

King post trusses were sometimes left open, as seen in the images above, but often, particularly in the northeastern states, the bridge was clad in boards or shingles.

King Post Truss Clad on Sheathing Boards King Post Truss Clad on Sheathing Boards

King Post Trusses Clad on Sheathing Boards: Image courtesy of Robert McCullough

The queen post truss, which consisted of two vertical posts intersecting the sides of a triangle and connected at the top by a horizontal beam, was suitable for slightly longer spans than the king post. These too were often sheathed in boards or shingles.

Queen Post Truss

Queen Post Truss: Image courtesy of Robert McCullough

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