Kinzua Bridge

Geobox|Bridge
name = Kinzua Bridge
other_name = Kinzua Viaduct
category = Railway bridge
etymology_type = Named for
etymology = Kinzua Creek

---

caption = The bridge in spring 2001, before its collapse.
country = United States
country_

state = Pennsylvania
state_

region_type = County
region = McKean
parent_type = Rail
parent = Single standard gauge track
river_type = Crosses
river = Kinzua Creek
length_imperial = 2052
length_note =
width_imperial = 10
height_imperial = 301
height_note =
weight_imperial = 6715000
weight_note = .cite web |url=http://www.dcnr.state.pa.us/stateparks/parks/kinzuabridge.aspx |title=Kinzua State Park
accessdate=2007-10-04 |publisher = Pennsylvania Department of Conservation and Natural Resources]
lat_d = 41
lat_m = 45
lat_s = 45.28
lat_NS = N
long_d = 78
long_m = 35
long_s = 18.52
long_EW = W
style_type = Design
style = Trestle
material = Steel
author_type = Builder
author = Elmira Bridge Company
established_type = Built
established = 1882
established_note =
established1_type = Reconstructed
established1 = 1900
established1_note =
established2_type = Collapsed
established2 = July 21, 2003
management_type =
management =
free1_type = Added to NRHP
free1_label = Year added to the National Register of Historic Places
free1_note =
free1 = 1977


map_caption = Location of the Kinzua Bridge in Pennsylvania
map_locator = Pennsylvania
map1 = Map of USA PA.svg
map1_caption = Location of Pennsylvania in the United States
commons = Kinzua Bridge

The Kinzua Bridge, also known as the Kinzua Viaduct, was a railway trestle that spanned the Kinzua Creek in McKean County in the U.S. state of Pennsylvania until a portion of it collapsed in 2003. The bridge was convert|301|ft tall and convert|2052|ft long.

Originally built out of iron in 1882, it was the tallest railroad bridge in the world until 1885. 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.cite journal| journal=Trains |month=October|year=2003|volume=63|issue=10| pages=25|title=Tornado Tears Down Historic "Kinzua Viaduct"] 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 the Kinzua Bridge State Park off of U.S. Route 6 near Mount Jewett, Pennsylvania.

History

In 1882, the () had the Phoenix Bridge Company design a bridge to be able to span the Kinzua Valley. The only other alternative to building a bridge was the laying of an additional convert|8|mi|km of track over rough terrain.

The first Kinzua Bridge was built from 1,552 tons (1,408 tonnes) of wrought iron in 94 days by a crew of less than a hundred.cite web|publisher=American Society of Civil Engineers|title=History and Heritage of Civil Engineering - Kinzua Railway Viaduct|accessdate=2007-10-02|url=http://live.asce.org/hh/index.mxml?lid=102] cite news|publisher=Pittsburgh Post-Gazette| author=Associated Press|original=2003-07-22|title=High Winds Topple Historic Railroad Bridge |url=http://www.post-gazette.com/localnews/20030722kinzuar5.asp|accessdate=2007-10-03] The reason for the short construction time was that scaffolding was not used in the bridge's construction, instead a was used to build the first tower and then a crane was built on the tower to build the second tower. The process was then repeated across all twenty towers. Because the bridge was built using "Phoenix columns" (hollow iron tubes patented by the Phoenix Bridge Company), it was mistakenly believed that it was built out of wooden poles.

On its completion, the bridge was the tallest railroad bridge in the world and was advertised as the "Eighth Wonder of the World."cite journal |last=Thornton |first=W. George |title=Tracks across the Sky |date=August 1949 |journal=Erie Railroad Magazine |pages=4–7] Excursion trains from as far away as Buffalo, New York and Pittsburgh would come just to cross the bridge. The Kinzua Bridge held the record until the convert|401|ft|m|0|sing=on high Garabit Viaduct in France was completed in 1885.cite web |title=Historical Markers - Kinzua Viaduct |date=2003 |publisher=Pennsylvania Historical and Museum Comission |accessdate=2008-06-23 |url=http://www.explorepahistory.com/hmarker.php?markerId=641] Trains were restricted to a speed of convert|5|mph|km/h|lk=on while crossing the bridge because the train, and sometimes the wind, would cause the bridge to start vibrating.

Reconstruction

In 1900, with the advent of heavier locomotives and rail cars, the Kinzua Bridge was abandoned and was dismantled on May 24.citation |last=Packard |first=Vance |publisher=Pennsylvania Historical and Museum Commission |date=1977-01-25 |title=National Register of Historic Places -- Nomination Form |location=Harrisburg |url=http://www.arch.state.pa.us/pdfs/H000610_01B.pdf |accessdate=2008-04-24] The new bridge was built by the Elmira Bridge Company out of 3,358 tons (3,046 tonnes) of steel. The engineer Octave Chanute designed the new bridge to prevent it from vibrating and swaying in the wind. The bolts used to hold the towers to concrete anchor blocks were reused from the first bridge, a move which would play a major role in the bridge's demise. Rail traffic resumed over the bridge on September 25, 1900. 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 June 21, 1959 and the Erie Railroad sold the bridge to a salvage company. The bridge was reopened for one day in October the same year when a wreck on the nearby Baltimore and Ohio Railroad caused trains to be rerouted across the bridge.

In 1963, the bridge was sold by the salvage company to the state, 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. The bridge was named to the National Register of Historic Civil Engineering Landmarks in 1977. The Knox and Kane Railroad operated sightseeing trips from Kane through the Allegheny National Forest and over the Kinzua Bridge from 1987 until the bridge was closed in 2002.

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. In February 2003, an Ohio–based bridge construction and repair company started work on restoring the Kinzua Bridge.

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. 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. [cite web| url=http://www.dcnr.state.pa.us/info/kinzuabridgereport/kinzua.html| author=Board of Inquiry Investigation |title =Report on the July 21st collapse of the Kinzua Viaduct| accessdate=2007-10-02| publisher=Pennsylvania Department of Conservation and Natural Resources]

The state opted not to rebuild the bridge, which would have cost an estimated $45 million. Instead, the state intends for the ruins to become a visitor attraction to show the forces of nature at work. In late 2005, the Pennsylvania Department of Conservation and Natural Resources put forward an $8 million proposal towards a new observation deck giving access to the bridge and a hiking trail giving views of the fallen towers. However, these plans have not yet been finalized.cite journal |last=Genshiemer |first=Lisa |title=Hope for the Kinzua Viaduct |journal=SIA Newsletter |publisher=Society for Industrial Archeology |date=Fall 2005 |volume=34 |issue=4 |pages=10–11 |accessdate=2008-04-27 |url=http://www.sia-web.org/sian/images/sianv34/sianv344.pdf |format=PDF]

The Kinzua Bridge was used as an example in the History Channel's "Life After People" of how corrosion and high winds would eventually cause all steel structures to collapse. [cite video |people=David de Vries (Director) |title=Life After People |publisher=History Channel |medium=Documentary |date2=2008-01-21]

Kinzua Bridge State Park

The Kinzua Bridge State Park is a convert|329|acre|ha|adj=on Pennsylvania State Park surrounding the bridge and the Kinzua Valley. The park is located off of U.S. Route 6 north of Mount Jewett. It is one of twenty-one chosen by the Pennsylvania Bureau of Parks for its "Twenty Must-See Pennsylvania State Parks" list. [cite web| url = http://www.dcnr.state.pa.us/stateparks/twenty/20parks.aspx | title = Twenty Must-See Pennsylvania State Parks | accessdate = 2007-08-08| publisher = Pennsylvania Department of Conservation and Natural Resources "Note: Despite the title, there are twenty-one parks in the list, with Colton Point and Leonard Harrison State Parks treated as one."]

A scenic overlook allows views of the fallen bridge and of the valley. The overlook is also a prime location to view the fall foliage during the first two weeks of October. The park also has a shaded picnic area with a centrally located modern restroom. Prior to the bridge's collapse, visitors were allowed on or under the bridge and hiking was allowed in the valley around the bridge.

See also

*List of bridge disasters
*Tay Bridge Disaster

References

External links

* [http://www.dcnr.state.pa.us/info/kinzuabridgereport/anim2.html Animation of the Kinzua Bridge Collapse] (30 MiB)
* [http://www.open2.net/sciencetechnologynature/worldaroundus/kinzua_partone.html Open University/BBC documentary on the bridge]