Swiftwater Covered Bridge, Bath New Hampshire

Date added: April 06, 2024

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The present Swiftwater Bridge at Swiftwater Village is the fourth bridge to cross the Wild Ammonoosuc River at this site. The first bridge was built in 1810 and carried away by a flood in 1818; it was replaced in 1818 by a bridge that was destroyed by flood in 1828. The bridge was replaced again in 1829, this replacement remained on the site until 1849 at which time it was dismantled and replaced by the current bridge.

Little mention is made of this bridge in the town meeting records at the time of its construction, for this reason, it would seem likely that supervision of its construction fell to the town surveyors of highways and bridges who were Joseph Fifield and John H. Carbee at the time. Both men had had a hand in the construction of the Bath Covered Bridge at Bath Village in 1831-32.

The bridge is constructed in an unpatented truss design, developed by Peter Paddleford of Littleton, New Hampshire. The truss was spread by Paddleford and his assistants; making some connection between the Swiftwater Bridge and members of Paddleford's group likely.

At the time of the bridge's construction, it served a logging community that had developed at Swiftwater village. The bridge has a tradition of having survived many log jams, one of which is said to have been cleared by dynamite with many of the logs landing on the roof of the bridge without destroying the structure.

Since its construction, the bridge has been maintained solely by the town of Bath without the use of state aid money. The bridge remains in use by a small residential population with a load limit of six tons.

Bridge Description

The Swiftwater Bridge crosses the Wild Ammonoosuc River on one span at Swiftwater village of Bath. The bridge connects Valley Road, a town road, on the north and south banks of the river.

The bridge is of Paddleford truss design with an arch. The truss is made of twenty braced panels separated into groups of nine on the bridge's north end and eleven on the bridge's south end by an unbraced, narrower panel. Each group is arranged about its own center, moving northerly, the center of the group of eleven panels occurs at the post shared by the sixth and seventh panels, while that of the nine-panel group occurs between the fourth and fifth panels, moving northerly from the center unbraced panel. Panels are framed by 9" x 9" posts into which braces (8½" x 5") are notched, and arranged about the centers described above. Counter-braces (7" x 3½") are wooden pinned to the inside faces of both posts and braces. The upper and lower chords are constructed of two sets of paired boards (each set with an overall size of 6" x 9½"). Each set is separated from its opposite member by a space of 3½" through which a notched part of each post passes and is pinned into place. The counterbraces pass between the two members of the inside set of each chord where they are notched and pinned into place.

The truss is laterally braced by beams that extend across the roadbed and jointed and wooden pinned to the top of each post. These beams are cross-braced to each other by diagonals, except for the bay which corresponds to the unbraced panel of the truss walls.

Set inside the truss, rising from the abutment faces are two laminated wooden arches, each of fourteen members iron bolted and bracketed together with a combined size of 9½" x 35". Each arch has twelve iron suspension rods connecting to beams beneath the roadbed. Some of the iron bolts and especially the iron brackets near each abutment show signs of heavy corrosion, with a few of the brackets having corroded completely through.

The truss rests on timbers set on concrete footings at the top of each abutment. Both abutments are rectangular-shaped and constructed of some split granite and some irregular stones, laid up without mortar, except some new mortaring on the river face of each abutment.

The bridge has an overall length of 173'8" with a roadbed of 158'2"; its overall width is 20'10½" with a roadbed of 16'6½" the portals have a vertical clearance of 11'4" which is posted. The roadbed of the bridge is made up of a larger center section of planks laid diagonally to the direction of the road flanked on either side by planks laid in the direction of the road. The roof is covered in corrugated metal and is set on a frame of rafters rising from the tops of the posts to a ridgepole which is further supported by diagonals extending from the inside face of most posts to the rafters near their junction with the ridgepole. The north end of the bridge has charred roof supports with some char marks on a few of the posts, confined mainly to the northwest side. The exterior of the bridge is sheathed in vertical boarding to an average height of eight feet above the roadbed, with one window in each of the two unbraced panels (one on either wall of the bridge). Both portals are covered in shingles, with some signs of damage to the south portal by a vehicle that was too high to pass. All exterior wood is weathered gray.

The bridge has been assigned the following numbers: 29-05-01 in the World Guide to Covered Bridges published by the National Society for the Preservation of Covered Bridges; 163-053 by the New Hampshire Department of Public Works and Highways and 29 by the New Hampshire Department of Resources and Economic Development.

The bridge was originally constructed without arches; when this alteration was made is not known.