Jump to content

Covered bridge: Difference between revisions

From Wikipedia, the free encyclopedia
Content deleted Content added
No edit summary
Line 98: Line 98:
* [[List of Indiana covered bridges]], 98 bridges
* [[List of Indiana covered bridges]], 98 bridges
**[[Parke County Covered Bridges]], 32 bridges
**[[Parke County Covered Bridges]], 32 bridges
* Iowa covered bridges
**[[List of Madison County Covered Bridges]], 6 bridges
* [[List of Michigan covered bridges]], 9 bridges
* [[List of Michigan covered bridges]], 9 bridges
* [[List of Missouri covered bridges]], 4 bridges
* [[List of Missouri covered bridges]], 4 bridges

Revision as of 07:52, 22 May 2009

Covered Bridge
The Cogan House Covered Bridge over Larrys Creek Cogan House Township, Pennsylvania, U.S.
AncestorTruss bridge, others
RelatedTubular bridge, Skyway, Jetway
DescendantNone
CarriesPedestrians, livestock, vehicles
Span rangeShort
MaterialTypically wood beams with iron fittings and iron rods in tension
MovableNo
Design effortLow
Falsework requiredDetermined by enclosed bridge structure, site conditions, and degree of prefabrication

A covered bridge is a bridge, often single-lane, with enclosed sides and a roof. They have typically been wooden, although some newer ones are concrete or metal with glass sides. Especially associated with the nineteenth century, covered bridges often serve as prominent local landmarks and have long attracted the attention of historic preservationists.

Construction details

Early bridges were often 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 Europe

The Western tradition of covered bridges originated in Central Europe.

Surviving or reconstructed European covered bridges include:

Famous stone covered bridges include the Rialto Bridge in Venice, Italy which for long was one of only three over the Grand Canal and a popular tourist attraction.

The Bridges of Sighs in Venice, Cambridge and Oxford are also covered bridges.

Covered bridges in North America

Green River Bridge in Guilford, Vermont
A modern covered bridge in Whiteside County, Illinois
A covered horse bridge at the race track in Bowie, MD

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, Wisconsin, and the New England states 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 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 1,000, 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 2008, the longest covered bridge in the United States is the Smolen-Gulf Bridge spanning the Ashtabula River near Ashtabula, Ohio.

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 in North America; that is, a bridge with two traffic lanes separated by a supporting truss. There are other double-barreled bridges in Vermont (2), Ohio (1), Indiana (1), and West Virginia (1).

Covered bridges are generally considered old-fashioned and appeal to tourists, but the enclosure acts as weather protection over the working part of the structure. 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 ones in Newton Falls, Ohio and Elizabethton, Tennessee, also feature an integrated covered walkway.

Covered bridges in Asia

Dong Minority Bridge, Chenyang, Guizhou, China.

In Asia, covered bridges are most prevalent in China, where they are called lángqiáo (廊桥). There are many covered bridges, called "wind and rain bridges" in the Chinese province of Guizhou. These were traditionally built by the Dong minority people. There are also many covered bridges in the Fujian province of southern China.[1]

Taishun County, in southern Zhejiang province near the border of Fujian, has more than 900 covered bridges, many of them hundreds of years old, as well as a covered bridge museum.[2] [3] There are also a number in nearby Qingyuan County, as well as in Shouning County, in northern Fujian province.

There is a well known covered bridge in Hoi An, Vietnam (in the Quang Nam Province of Vietnam's South Central Coast), called Chùa Cầu—the Japanese Bridge (illustrated in Gallery, below).

Modern covered bridges

Template:FixBunching

File:Guilford vermont bridge covered bridge interior 20040820.jpg
Plank-lattice truss interior structure of Green River Bridge in Guilford, Vermont
Baumgardener's Covered Bridge, employing the Burr Truss

Template:FixBunching

Modern covered bridges are usually for pedestrians, for example to walk from one part of an office building to another part, to cross railway tracks at a station, or in a shopping center on an elevated level, crossing a road. See also skyway.

Glass-walled covered bridges are rather common at American airports, and some of those bridges can be found at John F. Kennedy Airport in New York City.

Also, some highway bridges, such as the George Washington Bridge, have lower decks for additional capacity, and those decks, while generally open on the sides, can be enclosed with plastic from time to time during construction, thus rendering the lower decks as partially covered bridges.

The Bloor-Danforth subway in Toronto,Canada, crosses the Rosedale Ravine on a covered bridge made of concrete[2].

Covered bridges in fiction

North American covered bridges received much recognition as a result of the success of the novel, The Bridges of Madison County written by Robert James Waller and made into a Hollywood motion picture starring Meryl Streep and Clint Eastwood.

The fictional rural town portrayed in the 1988 film Beetlejuice features a covered bridge. It provides the early scene in which the protagonists (played by Alec Baldwin and Geena Davis) are killed when their car crashes through the wall of the bridge and plunges into the river below.

A covered bridge is featured in the 1999 film Sleepy Hollow in a scene depicting an encounter between main character Ichabod Crane (played by Johnny Depp) and the main villain, The Headless Horseman (played by Christopher Walken).

See also

Lists of extant historic covered bridges by U.S. state

References