Inclined Plane Bridge
Coordinates: 40 ° 19 ′ 33 " N , 78 ° 55 ′ 32" W.
| Inclined Plane Bridge | ||
|---|---|---|
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| use | Road traffic | |
| Convicted | SR 3022 | |
| Subjugated | Stonycreek River | |
| place | Johnstown , Pennsylvania , USA | |
| Entertained by | PennDOT | |
| Building number |
NBI # 113022001000000 HAER # PA-454 |
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| construction | Pennsylvania girder truss bridge made of wrought iron and steel | |
| overall length | 70.8 m | |
| width | 5.2 m | |
| Load capacity | 23 short tons | |
| start of building | June 11, 1890 | |
| opening | June 1, 1891 | |
| planner | Sparks & Evans (Phoenix Bridge Company) | |
| location | ||
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Highway Bridges Owned by the Commonwealth of Pennsylvania, Department of Transportation TR ( MPS ; PDF; 2.2 MB) |
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The Inclined Plane Bridge is a 232 foot (70.8 m) long continuous beam - truss bridge that the Stonycreek River in Johnstown in Cambria County in the State of Pennsylvania crossed. It connects the city with the valley station of the Johnstown Inclined Plane , a funicular . The bridge was added to the National Register of Historic Places on June 22, 1988 as part of Highway Bridges Owned by the Commonwealth of Pennsylvania, Department of Transportation TR . In 1997 it was documented for the Historic American Engineering Record (HAER).
history
On May 31, 1889, the South Fork Dam on the Little Conemaugh River above Johnstown collapsed after heavy rains had caused the water level to rise. The resulting tidal wave devastated the city and more than 2000 residents of the valley were killed. When the city was being rebuilt, the Cambria Iron Company began building apartment blocks on Yoder Hill that towered over the city. In order to create easy access to the new Westmont settlement despite the steep slope and at the same time to provide an escape route in the event of future flood disasters, the company decided to build a funicular. In order to connect the valley station of this mountain railway to the city, the construction of a bridge was necessary, as the city and valley station were on the opposite banks of the Stonycreek River.
Construction began on June 11, 1890, and the excavations for the bridge's abutments were completed a week later.
On March 17, 1936, almost 4,000 people huddled on the bridge ramp, the bridge itself and numerous boats to take the mountain railway to safety because the Stoneycreek and Conemaugh rivers had overflowed their banks. Further downstream, this flood in Pittsburgh had devastating effects.
The Works Progress Administration allocated $ 17,812 in October 1936 to repair the bridge ramp and replace the railing posts, handrails, and the road surface. The Pennsylvania Department of Highways, the precursor to the Pennsylvania Department of Transportation (PennDOT), bought the bridge in 1964. Starting September 1, 2000, PennDOT invested US $ 2.3 million to renovate the bridge and the road leading to it. The work was interrupted from April to September 2001 in order to enable the operation of the mountain railway in the summer months. The renovation measures were completed on December 14, 2001.
design
When the Inclined Plane Bridge was built, parts made of wrought iron and steel were riveted together to form a truss bridge with continuous Pennsylvania girders. A Pennsylvania (or Petit) girder is basically a Pratt girder in which the outer longitudinal girders are set polygonally and have dividing panels to reinforce the girder under heavy loads. At 232 feet (70.8 m) in length, the Inclined Plane Bridge is relatively short for a Pennsylvania girder bridge that was typically only built between 250 and 600 feet in length.
literature
- J. Philip Gruen: Inclined Plane Arch Bridge ( English ) In: Historic American Engineering Record . National Park Service. 1997. Retrieved January 24, 2011.
supporting documents
- ^ Federal Highway Administration : Place Name: Johnstown, Pennsylvania; NBI Structure Number: 113022001000000; Facility Carried: SR 3022; Feature Intersected: Stoneycreek River ( English ) In: National Bridge Inventory . Nationalbridges.com (Alexander Svirsky). 2010. Retrieved January 25, 2011. ( Scraping version of the official website: PA09.txt ( English ) Federal Highway Administration. 2009. Retrieved January 25, 2011.)
- ↑ a b Gruen, p. 2.
- ↑ Gruen, p. 6.
- ↑ Gruen, pp. 8–9.
- ↑ Gruen, p. 9.
- ↑ Kenneth C Springirth: Johnstown Trolleys and Incline (= Images of Rail). Arcadia , Charleston , South Carolina 2006, ISBN 0-7385-4583-X , p. 118.
- ^ J. Dain Davis, Pennsylvania Department of Transportation: Bridge in Johnstown City ( PDF ; 247 kB) In: Pennsylvania Historic Resource Survey Form . Pennsylvania Historical and Museum Commission . September 20, 1982. Retrieved January 26, 2011.
- ↑ a b c Gruen, p. 7.