MapMuse - Locate Covered Bridges Near You

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Early bridges were made of wood, especially where it was a plentiful resource. Wooden bridges tended to deteriorate rapidly from exposure to the elements, having a useful lifespan of only nine years. Covering them protected their structural members, thus extending their life to 80 years or more. Covered bridges were also constructed to be used by travelers during storms and inclement weather.

Most wooden covered bridges employ trusses as their key structural design element. A popular design was the Brown truss, known for its simplicity, but others were also used.

Given the ready availability of steel, concrete, and other modern construction materials, most modern covered bridges are built either for the convenience of the user, rather than to protect the structure itself, or as a statement of style or design.

Covered bridges in North America

Such bridges are found in rural areas throughout the United States and Canada, but are often threatened by arsonists, vandals, and flooding. In the United States, Pennsylvania has more covered bridges (over 200) than any other state, many of which can be seen in Washington, Chester and Lancaster Counties. The U.S. state of Vermont has more covered bridges per square mile than any other place in the world, with 107 bridges located throughout the state. Oregon has the largest number of historical covered bridges in the western United States.[1] They are also common in places such as Elizabethton, Tennessee, Lane County, Oregon, Madison County, Iowa, Parke County, Indiana, and Blount County, Alabama. Parts of California, Indiana, Ohio, Michigan, Kentucky, Maryland, Minnesota, Virginia, West Virginia and the New England states also have surviving covered bridges.

There are various structural designs used for covered bridges, such as the Burr Truss.

Opened on July 4, 1901, the 1,282 foot (390 m) Hartland Bridge, crossing the Saint John River at Hartland, New Brunswick, is currently the longest covered bridge in the world. It is a national historic site. In 1900, New Brunswick had an estimated 400 covered bridges, and Quebec more than 1000, while Ontario had only 5. As of 2006, there were 94 covered bridges still standing in Quebec, 65 in New Brunswick and at least two in Ontario.

A much longer covered bridge (5,960 ft) between Columbia and Wrightsville, Pennsylvania once spanned the mile-wide Susquehanna River, making it the longest and most versatile covered bridge in the world during its existence. It featured railroad tracks, a towpath for canal boats crossing the river between two canals on either bank, and a carriage / wagon / pedestrian road. The popular toll bridge was burned June 28, 1863, by Union militia during the American Civil War to prevent its usage by the Confederate Army of Northern Virginia during the Gettysburg Campaign. A replacement wooden covered bridge was destroyed by a windstorm a few years later. It was rebuilt as an open-air steel bridge.

As of 2006, the longest existing covered bridge in the United States is Medora Covered Bridge in Indiana, which is 458 feet (140 m) in length; however, Ashtabula County, Ohio, is in the process of breaking that record. Construction is underway on a new 600-foot (180 m) covered bridge, which will span the Ashtabula River near Ashtabula. The bridge should be completed before Fall 2008[2], and will be the 5th covered bridge built in Ashtabula County since 1983. The town of Blenheim, New York has the longest single-span covered bridge in the world (232 ft), built in 1855. The bridge crosses the Schoharie Creek in the northern Catskills. It is one of only six "double-barreled" covered bridges still in existence in North America; that is, a bridge with two traffic lanes separated by a supporting truss. Other double-barreled examples exist in Vermont (2), Ohio (1), Indiana (1), and West Virginia (1).

Covered bridges are generally considered old-fashioned, and appeal to tourists, but the purpose is twofold: (1) covered bridges appear similar to barns and it is easier to transport cattle across them without startling them, and (2) to build a structure for weather protection over the working part of the bridge. A bridge built entirely out of wood, without any protective coating, may last 10 to 15 years. Builders discovered that if the bridge's underpinnings were protected with a roof, the bridge could stand for 70, or even 80 years. The existing covered bridges have been renovated using concrete footings and steel trusses to hold additional weight and to replace the original support timbers.Some covered bridges, such as the one in Newton Falls, Ohio and Elizabethton, Tennessee, also feature an integrated covered walkway.