Ashuelot Covered Bridge, Ashuelot New Hampshire
Winchester New Hampshire, is a large and sparsely-populated township measuring approximately six by eight miles. The township includes two principal villages, Winchester and Ashuelot. Both villages grew in response to water power afforded by the Ashuelot River, considered one of the most important manufacturing streams in the state after the Civil War. By 1864, when the bridge was constructed, the villages of Ashuelot and Winchester supported woolen mills, manufactories of wooden products, machine shops, and stores, all connected to other Connecticut Valley towns in New Hamsphire and Vermont, and ultimately to Boston, by the Ashuelot and Cheshire Railroads. The Ashuelot Railroad, incorporated in 1844, completed in 1851 and eventually absorbed into the Boston & Maine system, passed within yards of the southern abutment of the Ashuelot bridge.
This bridge provided the only means by which highway traffic could cross the river in the village of Ashuelot and connected the main settlement, on the north side of the stream, with a smaller settlement and the railroad depot on the south. No less than five roads converged near the north end of the bridge, and a hotel and public library were eventually built at this focal point. Near each end of the bridge, roads ran east to connect Ashuelot with the village of Winchester. Thus the Ashuelot covered bridge was, and remains, a vital transportation link in the small village, permitting highway transportation between the two sides of the river, between Ashuelot and Winchester, and between the main street of Ashuelot and its vital railroad connection on the opposite side of the stream. The bridge continues to carry automobile and foot traffic but is closed to heavy trucking.
Winchester had been discussing building new bridges over the Ashuelot since 1853. The town warrant for the bridge that was finally constructed reads: "Article 15--To see if the town will vote to build an X or Lattice Bridge with split stone abutments, a sidewalk on open sides over the Ashuelot River at Ashuelot at or near the place where the old bridge now stands, choose a building committee and raise money therefore and act thereon." It was voted March 8th, 1864, to proceed and by March 10th, 1865, the bill of $4,650 was registered as paid.
The bridge was built where an old one stood, incorporating some members of the old bridge, for a wooden beam with an earlier date than 1864 was removed when repairs were made after the 1936 hurricane.
The Town lattice truss was an uninterrupted series of crisscrossed diagonals in construction forming what were overlapping triangles. In such trusses, any load on any one triangle affects the distribution of stress in all other triangles. The web members were fastened at their points of intersection so that independent action of any one triangle was impossible. Therein lay the great strength of the Town truss. It was a real invention, not resembling any design advanced for wooden spans in the thousands of years before its time that bridges had been built.
Ithiel Town's lattice design was not only original but it met a need that other bridge designs could not. It could be erected by a common carpenter's gang. This was no small consideration when New England towns had to undertake a task of expensive proportions. But since the construction could be locally executed, each bridge beyond the basic trusswork, was an expression of the natives' taste; and so might be considered a form of folk art. Certainly, the Ashuelot Bridge is unique.
The Town lattice truss was favored for bridge construction because of its simple design, its proven strength, and the fact that its use required no skill in formal engineering. The truss was an indeterminate structure and was not susceptible to the methods of structural analysis that were coming into use in the United States by the time of the Civil War. The properties of the Town truss were understood empirically, however, and the invention was therefore used not only for highway bridges but also for railroad spans that were required to withstand far greater static and dynamic stresses.
The trusses of the Ashuelot bridge are typical of the lighter form of web used for highway spans. Such trusses have only one set of diagonals in each direction rather than the doubled sets used in most railroad bridges. Each truss is continuous and uniform for the full 178-foot length of the structure; this uniformity, which pays no regard to the presence or absence of a central pier, is characteristic of Ithiel Town's patent. Because Town's truss is indeterminate and was not designed according to structural analysis, its design did not require a two-point support system as did trusses in which stresses were calculated. The central pier of the Ashuelot bridge therefore added support to the truss without changing its structural character. The pier was probably added more as a safety factor than as a necessity, since experience had shown that Town trusses could be constructed with a much greater unsupported span than that used in the Ashuelot bridge; the Blenheim bridge (1853) over Schoharie Creek in North Blenheim, New York, used Town trusses with a clear span of 228 feet.
Bridge Description
The Ashuelot Bridge spans the Ashuelot River in the unincorporated village of Ashuelot, Town of Winchester. The National Society for the Preservation of Covered Bridges' World Guide to Covered Bridges' number is 29-03-02. The New Hampshire Department of Public Works and Highways' number is 082/087.
The bridge is 178' long; the roadway is 17' wide with 11'10" overhead clearance. The overall width of the bridge is 29', the sidewalks being 3'10" wide. The bridge crosses the river in two spans, supported by coursed, split granite abutments and a central pier. Concrete platforms have been added to the bases of the supports and the center pier has been equipped with a metal breakwater. The only cement pointing occurs in the upper courses of the center support, probably applied when the reinforcing platforms were added.
The bridge has been closed to trucks because many of the roadbed beams under the bridge are broken.
The bridge's trusswork follows Ithiel Town's Lattice design. Normally, a covered bridge's sides are sheathed to protect the all-important trusswork. It was also this sheathing that was the most expensive element of the bridge. The Ashuelot Bridge is protected in three ways: 1. There are walkways on both sides so that the roof extends a distance beyond the trusswork, 2. The sidewalks are vertically sheathed to just below the handrail height. 3. The bridge is presently painted white. Whether the bridge was painted during the last century would be difficult to say categorically. There does not seem to be a great deal of paint build-up, but then, perhaps the bridge was not repainted often.
Lacking siding, the lattice design gives a lightness and decorative feeling to the bridge. This seems to have inspired the builders to elaborate on the structure's details. The roof is of medium pitch, presently covered in tin, painted red. There is a cornice fascia alone over the rafter ends. The verges project with a frieze just beneath. The gables are finished in functional board and batten, although this is often interpreted as Gothic gingerbread. The real gingerbread occurs with the flat and round corner trim over the road portal and the center ogee trim over the walkways, all of which are painted red. The gable overhang arches out gently to meet the traveler. It is supported on the cased-in portals by curved, projecting brackets that are horizontally paneled. The overhang is upheld on the exterior by the slender, chamfered posts that hold up the roof the length of the sidewalks.
The eastern walkway has a boxed-in pipe running its length and is supposed to be closed to foot traffic.
North portal and west side (1974)
