West Cornwall Bridge, Cornwall Connecticut

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The West Cornwall Bridge is one of three remaining covered bridges in Connecticut and displays an important engineering innovation. Due to their resistance to decay, covered bridges were extremely common throughout America in the 19^th century, yet comparatively few remain.

Built in 1841, this bridge is built using the Town Lattice Truss, a series of closely spaced, overlapping triangles with neither arches nor uprights. Because it avoided the serious problem of fatigue at the joints between uprights and diagonals, this truss was strong and durable, and exceptionally easy to construct. Most of the stress was borne by the pegs at each point where the triangles overlap, but since there are so many, no individual point is critical. For these reasons, it became one of the most popular forms of support for wooden bridges.

Although today he is recognized primarily as one of America's foremost architects, Ithiel Town (1784-1844) achieved great fortune and world renown through the invention of his lattice truss. Because he collected $1 per foot in royalties and $2 per foot if he discovered an infringement of his patent, Town made it a habit to visit in person Northern communities where bridges were being built or considered. Interestingly, the construction of the West Cornwall Bridge is said to have been supervised by Town himself, but even if not, the 242' span remains an excellent example of a major innovation in bridge design.

Bridge Description

The West Cornwall Bridge crosses the Housatonic River at one end of a small village of 19th-century houses, shops, studios, and restaurants. Because it is still in use, it has undergone several modifications. Nevertheless, this covered bridge retains its historical appearance. Its board-and-batten sides, painted red, are broken at irregular intervals by small window openings, most with 6-pane sash, though some are unglazed. The square portals are approximately 12' wide and 11' high, and the moderately pitched roof is covered with white cedar shingles.

Originally built as a single 242" span, the bridge was strengthened in 1924 by the addition of a central concrete pier. The original abutments, of unmortared rubble, have also been reinforced with cement. The primary structural member is a Town Lattice truss, held together by large wooden pegs; secondary support is provided by a kingpost truss pegged to both sides of both lattices. Although these members are all still in place, a steel deck, concealed beneath the diagonally laid plank floor, actually carries the load. The deck is not visible except from the river which was about 12' below the bridge. To install the deck, the entire bridge was raised 2'; the abutments and pier were heightened with concrete, and the approaches to the bridge were reconstructed. At the same time (about 1972), many repairs, including a new roof, were made.

(1975)

(1975)

(1975)