Covered Bridges
By: Ruth Shireman and Nancy Avolese
Lower Swatara Township has had two well-known covered bridges. The first one, Fiddler’s Elbow Covered Bridge connected Lower Swatara Township with Derry Township over the Swatara Creek by way of North Union Street to Fiddler’s Elbow Road. It was built in 1862 and was 235 ft long.
The second bridge was the Clifton Bridge. This bridge stood at the east end of Fulling Mill Road and spanned across the Swatara Creek connecting Londonderry Township with Lower Swatara Township.
Both covered bridges were built using the Burr Truss method.
Theodor Burr built a bridge across the Hudson River in Waterford, NY in 1804. There he used a combination truss and segmented arch that became the basis of his 1817 patent. The patented truss consisted of parallel wooden cords tied together by vertical posts and stiffened by crossed wooden braces. Each timber arch support segment is fitted into both sides of the wooden posts and braces. The arch serves to make the whole structure more ridged. The segments are bolted into the vertical posts, sandwiching the truss. The two long arches are to rest on the abutments on either end of the bridge.
Wooden bridges were entirely exposed to the elements and were quickly attacked by decay. To protect these exposed structures, it was usual to roof and side the bridges, resulting in the “covered bridge” concept to help them survive. This form of protection for wooden bridges was almost always applied, to large as well as small bridges.
It has been said that some horses, that were easily spooked, were more willing to enter a closed structure that looked like a barn or shed.
Because covered bridges were located in strategic locations and many people used them, they were a popular place to post advertising. The photo of the Clifton Bridge, above center, had an undertaker's ad on it.
Both bridges were destroyed during the Agnes Flood of 1972.
Sources:
“Spanning Time, Vermont’s Covered Bridges” by Joseph C. Nelson
“The Burr Truss” by J. B. Calvert, University of Denver, October 23, 2000.
Covered Bridges of Pennsylvania Dutchland, 1960.