Covered Bridges in the United States
Adapted from the Covered Bridge Manual, U.S. Department of Transportation, April 2005
A covered bridge, by definition, is a timber structure supporting a deck surface that carries loads over an obstruction such as a river. The structural components are protetected from the elements by various coverings: wals, roofs and decks. Timber bridges initially were built without coverings and failed in just a few years due to rot and deterioration. The side-support trusses, roof and siding provided protection from the weather.
Covered bridges are disappearing from our landscape. At one time, the United States reportedly had 14,000 covered bridges. In 2005, the number had dwindled to fewer than 900. Bridges have been damaged by large truck and trailers, fires, flooding and/or vandalism. Maintenance costs are also factors. In 2022, Shimanek Covered Bridge was fully restored. The project cost $2.9 million dollars.
The oldest covered bridges are:
Hyde Hall Bridge in Oswego County, New York circa 1825
Havenhill-Bath Bridge at Woodsville, New Hampshire circa 1829
Roberts Bridge in Preble County, Ohio built in 1829
Oregon’s oldest remaining bridge is Drift Creek Covered Bridge, built in 1914.
Oregon’s Covered Bridge Timeline
1860’s - In response to floods and an increase in population, the first wave of covered bridge building begins in the Willamette Valley.
1861 - Many covered bridges are destroyed when the Willamette River swallowed riverside communities during Oregon’s biggest flood in recorded history.
1870 - A.S. Miller arrives in Oregon and brings the coveted covered franchise for Smith trusses with him. Nels Roney arrives in Oregon and begins working with A.S. Miller as a bridge builder.
1881 - Heavy snow melt and rain causes state-wide flooding. Scores of bridges are destroyed or damaged by rising waters. Nels Rooney goes into business as a bridge buildr and replaces many of the destroyed covered spans.
1890 - Another devestating flood. The Willamette River swelled just two inches below the 1861 flood level, making it the second 100-year class flood in 30 years.
1915 - Oregon State Highway Department begins to supply “standard” covered bridge designs to counties.
1918 - 1924 - Highway department improves on basic Howe Truss-based bridge design by adding windows, whitewash, laminated floors and asphalt surfaces.
1928 - Professor E.H. McAlister reports that Douglas-fir can be preserved in sound structural condition for at least 50 years by keeping it covered from weather and allowing air circulation.
1936 - Oregon State Highway Commission inventories rural roads indlucing all the covered bridges.
1948 and 1952 - Oregon State Highway Commission prints lists of covered bridges for tourists.
Resource
Lowell Covered Bridge Interpretive Center