Kinzua Bridge
From Wikipedia, the free encyclopedia
| Kinzua Bridge | |
| Kinzua Viaduct | |
| Railway bridge | |
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| Named for: Kinzua Creek | |
| Country |  United States |
|---|---|
| State |  Pennsylvania |
| County | McKean |
| Rail | Single standard gauge track |
| Crosses | Kinzua Creek |
| Coordinates | |
| Length | 2,052 ft (625 m) [1] |
| Width | 10 ft (3 m) |
| Height | 301 ft (92 m) [1] |
| Weight | 6,715,000 lb (3,045,873 kg) [2] |
| Builder | Elmira Bridge Company |
| Design | Trestle |
| Material | Steel |
| Built | 1882 [1] |
| - Reconstructed | 1900 [1] |
| - Collapsed | July 21, 2003 |
  Location of the Kinzua Bridge in Pennsylvania
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 Location of Pennsylvania in the United States
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| Wikimedia Commons: Kinzua Bridge | |
The Kinzua Bridge, also known as the Kinzua Viaduct, was a railway trestle that spanned Kinzua Creek in McKean County, Pennsylvania until it collapsed in 2003.
Originally built out of iron in 1882, it was the tallest and longest railroad bridge in the world. In 1900, the bridge was dismantled and then rebuilt out of steel. Before its collapse, the Kinzua Bridge ranked as the fourth tallest railway bridge in the United States.[3] It was listed on National Register of Historic Places and as a National Historic Civil Engineering Landmarks in 1977. The Kinzua Bridge is located in and is the namesake of the Kinzua Bridge State Park.
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[edit] History
In 1882, the New York, Lake Erie and Western Railway (NYLE&W) had the Phoenix Bridge Company design a bridge to be able to span Kinzua Gorge. The alternative to building a bridge over the gorge was laying an additional 8 miles (13 km) of track over rough terrian.[2] When asked by the NYLE&W if he could build a bridge 300 feet (91 m) tall, the superintendent for the Phoenix Bridge Company Adolphus Bonzano responded that he could "build... a bridge 1,000-ft [300 m] tall if you furnish the money."[4]
The first Kinzua Bridge was built from 1,552 tons (1,408 tonnes) of wrought iron[5] in 94 days by a crew of less than a hundred.[1][5] The reason for the short construction time was that scaffolding was not used in the bridge's construction, instead a gin pole was used to build the first tower and then a crane was built on the tower to build the second tower.[1][6] The process was repeated for all twenty towers. On its completion, the bridge was the tallest railroad bridge in the world.[3] The Kinzua Bridge held the record until the 401-foot (122 m) high Garabit Viaduct in France was completed in 1885.[7] Trains were restricted to a speed of 5 miles per hour (8.0 km/h) while crossing the bridge because the train would cause the bridge to start vibrating.[6]
[edit] Reconstruction
In 1900, with the advent of heavier locomotives and rail cars, the Kinzua Bridge was abandoned and was dismantled on May 24.[6] The new bridge was built by the Elmira Bridge Company out of 3,358 tons (3,046 tonnes) of steel. The bolts used to hold the towers to concrete anchor blocks were reused from the first bridge,[7] a move which would play a major role in the bridge's demise. Rail traffic resumed over the bridge on 1900-09-25. The Erie Railroad owned the bridge after the NYLE&W went bankrupt and was merged with the Erie Railroad in 1893. Regular commercial service ended on 1959-06-21 and the Erie Railroad sold the bridge to a salvage company. The Knox and Kane Railroad operated sightseeing trips across the bridge from 1987 until the bridge was closed in 2002.
[edit] State Park
In 1963, the bridge was sold by the salvage company to the state and William Scranton, then governor of Pennsylvania, signed legislation creating Kinzua Bridge State Park the same year, although the park did not officially open until 1970.[6] The bridge was named to the National Register of Historic Civil Engineering Landmarks in 1977. In 1987, the Knox and Kane Railroad started to run excursion trains across the bridge. The trains traveled from Kane through the Allegheny National Forest and made a stop on the bridge before returning to Kane.[2]
[edit] Destruction
In 2002, the Kinzua Bridge was closed to all "recreational pedestrian and railroad usage" after it was determined that the structure was at risk to high winds. Engineers determined that during high winds, the bridge's center of gravity would shift, putting weight onto only one side of the bridge and cause it to fail.[2] In February 2003, an Ohio–based bridge construction and repair company started work on restoring the Kinzua Bridge.[2]
At approximately 15:20 EDT (20:20 UTC) on July 21, 2003, a tornado touched down in Kinzua Bridge State Park. The storm, classified as F1 on the Fujita scale, snapped and uprooted nearby trees, as well as causing 11 of the 20 bridge towers to collapse. The failure was caused by the badly rusted base bolts holding the bases of the towers to concrete anchor blocks embedded into the ground.[2] The investigation hypothesized that the whole structure oscillated laterally 4 to 5 times before fatigue started to cause the base bolts to fail. The towers fell intact in sections and suffered damage upon impact with the ground.[8]
The towers were left where they fell and the ruins are intended to become a visitor attraction to show the forces of nature at work. The Pennsylvania Department of Conservation and Natural Resources put forward an $8 million proposal to build an observation deck giving access to the bridge and a hiking trail giving views of the fallen towers.[4]
The Kinzua Bridge was mentioned in the History Channel's Life After People as an example of how corrision and high winds would cause steel structures to eventually collapse.
[edit] See also
[edit] References
- ^ a b c d e f History and Heritage of Civil Engineering - Kinzua Railway Viaduct. American Society of Civil Engineers. Retrieved on 2007-10-02.
- ^ a b c d e f Kinzua State Park. Pennsylvania Department of Conservation and Natural Resources. Retrieved on 2007-10-04.
- ^ a b "Tornado Tears Down Historic Kinzua Viaduct" (October 2003). Trains 63 (10): 25.
- ^ a b Genshiemer, Lisa (Fall 2005). "Hope for the Kinzua Viaduct" (PDF). SIA Newsletter 34 (4): 10-11. Society for Industrial Archeology.
- ^ a b Associated Press. "High Winds Topple Historic Railroad Bridge", Pittsburgh Post-Gazette. Retrieved on 2007-10-03.
- ^ a b c d Packard, Vance (1977-01-25), National Register of Historic Places -- Nomination Form, Harrisburg: Pennsylvania Historical and Museum Commission, <http://www.arch.state.pa.us/pdfs/H000610_01B.pdf>. Retrieved on 2008-04-24
- ^ a b Leech, Thomas (July-August 2005). "The Collapse of the Kinzua Viaduct". American Scientist 93 (4): 348. Sigma Xi. doi:.
- ^ Board of Inquiry Investigation. Report on the July 21st collapse of the Kinzua Viaduct. Pennsylvania Department of Conservation and Natural Resources. Retrieved on 2007-10-02.
