Portageville Viaduct
Coordinates: 42 ° 34 ′ 40 " N , 78 ° 2 ′ 58" W.
| Portageville Viaduct | ||
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| Official name | High bridge | |
| use | Railway bridge | |
| Crossing of | Genesee River | |
| place | Portage, Letchworth State Park , NY | |
| construction | Trestle Bridge | |
| overall length | 244 m | |
| height | 71 m | |
| start of building | July 1851 | |
| completion | August 1852 | |
| planner | Silas Seymour (wood 1852) George S. Morison (iron 1875) |
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| closure | Fire in 1875, then a new iron building | |
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The Portageville Viaduct , also known as Portage Bridge known was a railway bridge near the town of Portage in today's Letchworth State Park in the State of New York in the United States .
Construction began on July 1, 1851; the first locomotive drove over the new bridge on August 14, 1852. The opening ceremony took place on August 25th. It burned down in 1875 and was replaced in the same year by an iron trestle bridge that was used until the end of 2017 .
description
The Portage Bridge was originally a single-track wooden trestle bridge on which the Erie Railroad trains between New York City and Buffalo crossed the Genesee River gorge at a height of 71 m (234 ft ).
The 800 ft (244 m) long bridge was covered with wooden planks and railings and was wide enough for passengers to get off at one of the occasional train stops and dare to look out over the river valley and the roaring Upper Falls just a few meters downstream .
The bridge was designed by Silas Seymour, the chief engineer of the Erie Railroad. It had 14 rectangular pillars including the 5 smaller pillars on the upper slopes. The larger pillars stood on 9 m high plinths made of sandstone - stone that was taken from the river bed. The bases were covered with limestone slabs. The plinth dimensions at the base are 23 m × 4.5 m (75 ft × 15 ft).
On the stone plinths stood the 58 m (190 ft) high wooden scaffolding pillars, which consisted of 21 vertical posts in the lower area and 15 in the upper area; these were stiffened by horizontal and diagonal connections. Each pillar had a mathematical load-bearing capacity of 1000 short tons (approx. 900 t). The 4.3 m (14 ft) high deck girder also consisted of a wooden framework. The wooden construction allowed individual defective parts to be replaced without any special measures to secure the surrounding areas. The fire hazard was seen as the greatest risk. On the other hand, water tanks had been set up and guards had been deployed.
The bridge itself was built from the east. As soon as the first pillar was finished, the deck girder and the track were built to it. The next pillar was built with a mobile crane, which in turn was connected to the track.
The wood used corresponded to approximately 100 hectares (250 acres ) of coniferous forest.
It has been estimated that the cost of a brick viaduct would have been more than seven times that, so the interest saved on the additional costs alone would have been enough to renew the bridge every few years. The bridge had no technical features, but was considered the tallest wooden trestle bridge of its time. Because of its high pillars, it is said to have influenced the construction of the first European railway viaducts with wrought iron structures.
Fire and new building
Foundations of the burned down bridge
The bridge, demolished in 2018
After 23 years of operation without any particular incident, a security guard noticed a fire on the night of May 5th to 6th, 1875, but was unable to extinguish it because of a jammed valve. The bridge was soon completely in flames and burned down to the base. The onset of light rain prevented further damage in the area.
Just four days after the fire, the Erie Railroad decided to have a new iron bridge built. In the rush, the plans had to follow the scheme, especially the bases of the old bridge. The new building could already be tested on July 31, 1875, initially only by one, and finally by a group of six locomotives.
Until the end it was essentially still in its original state of construction. Since it no longer met the current requirements for the permissible axle load , the Portageville Bridge was built right next to the old bridge by the end of 2017 . The old bridge was then torn down.
Web links
Individual evidence
- ^ A b Tom Cook: The Portage Bridge on the Letchworth State Park website
- ↑ The information is based on the article High Bridge, Portage, New York. (with sketch) from The Civil Engineer & Architect's Journal , London 1853
- ^ The Portageville Bridge Project on the Department of Transportation website
- ↑ Final days: Old Portage Viaduct to be demolished in 2018. Accessed September 7, 2019 .