A plaque near the bridge reads:
National Historic Civil Engineering Landmark
Bunker Hill Covered Bridge
The only remaining example of the Improved Lattice Truss timber bridge patented by Herman Haupt (1817-1905) in 1839. Haupt was Chief of Military Railroads for the Union Army during the Civil War. This Philadelphia born Civil and military engineer, author, inventor and industrialist was one of the first to develop a rational method of truss analysis. His 1851 book, "General Theory of Bridge Construction," is one of the earliest books on bridge engineering.
Constructed 1895
Restored in 1994
Designated in 2001.
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Designated as a National Civil Engineering Landmark in 2001, the Bunker Hill Covered Bridge is the only remaining example in wood of the Improved Lattice Truss patented by General Herman Haupt. It joins the Cape Hatteras Lighthouse, the Blue Ridge Parkway, and Dorton Arena in representing North Carolina on this prestigious list.
One of only two original remaining covered bridges in North Carolina, the other being Mt. Pisgah in Randolph County, the Bunker Hill Covered Bridge was built in 1895 by Andy L. Ramsour. Catawba County Commissioners in 1894 had called on nearby owners of Bunker Hill Farm to build and maintain a bridge that would cross Lyle’s Creek on the old Island Ford Road, a former Native American trail. The landowners hired Ramsour, keeper of the Horseford covered bridge that spanned the Catawba River north of Hickory. He likely found Haupt’s design in a popular book on bridge building.
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Originally constructed as an open span, the Bunker Hill Covered Bridge, whose roof is ninety-one feet long, was covered in 1900. In 1921 its wooden shingles were replaced with a tin roof. (Bridges were covered to protect their timbers from the elements; travelers enjoyed a reprieve from rain and snow only as a consequence.) Bolick Family members donated the bridge in 1985 to the Catawba County Historical Association, which restored it in 1994 with the expertise of Arnold M. Graton, a master bridgewright from Ashland, New Hampshire.
David Fischetti, from Cary, North Carolina, the consulting engineer for the restoration who initiated the bridge’s designation as a national landmark, notes that Brigadier General Herman Haupt (1817-1905) was Chief of Military Railroads for the Union Army during the Civil War. A Philadelphia born civil and military engineer, author, professor, inventor, and industrialist, “Haupt’s improved lattice truss bridge was a response to Ithiel Town’s 1820 and 1835 patents for the plank lattice timber truss. Haupt used the analytical methods he developed in the 1840s to design a more efficient lattice truss which consisted of web members positioned only at locations which required support. Redundant members were removed, resulting in the improved lattice truss as described in his book General Theory of Bridge Construction published in 1851.”
Haupt himself in his letter to the U. S. Patent Office (“Specification of Letters Patent No. 1,445, dated December 27, 1839”) writes, “What I claim as my invention is—The construction of a lattice bridge without counterbraces, but consisting simply of braces inclined at any proposed angle and ties which are perpendicular to the lower chord, the chords being either straight or curved.”
In his letter, Haupt delineates the faults of the lattice truss, which is “composed of a system of braces and counterbraces arranged at equal angles in opposite directions and pinned with wooden pins to horizontal chords at top and bottom. Theory, observation, and experiment all agree in favor of the conclusions that one half of the inclined pieces are of no use as counterbraces and badly answer the purpose of ties, that from their inclined position they are exposed to a very considerable cross strain, which tends to split the timbers along the line of pins, and that the pins of the lower intersections are caused to bear a disproportionate share of the weight.”
The Bunker Hill Covered Bridge has significant associations not only with the Civil War, through Haupt, but also with the American Revolution. Of the Island Ford Road, on which the bridge rests, Dr. J. E. Hodges, President of the Catawba County Historical Association in the 1950s, writes in 1959 that following the Battle of Cowpens in 1781, General Morgan detached 531 British prisoners under guard of Colonel William Washington’s dragoons and Colonel Charles McDowell over the Island Ford Road. The men crossed Lyle’s Creek at the Bunker Hill Ford on their way to the Island Ford of the Catawba River, where they were received by the Commissary of Prisoners and conveyed to the interior of Virginia.
The bridge is located two miles east of Claremont on Hwy. 70