Astoria Bridge
Coordinates: 46 ° 13 '2 " N , 123 ° 51' 46" W.
| Astoria Bridge | ||
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| use |
 US Route 101
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| Crossing of | Columbia River | |
| place | Astoria (Oregon) | |
| construction | u. a. Truss bridge | |
| overall length | 6.6 km | |
| width | 8.5 m | |
| Longest span | 375.5 m | |
| Clear height | 60 m | |
| start of building | 1962 | |
| completion | 1966 | |
| location | ||
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| The north end of the bridge | ||
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The Astoria Bridge (also Astoria-Megler Bridge, Columbia River (Astoria) Bridge ) is a road bridge over a 6 km wide at this point, the border between the US states Oregon and Washington Fine Columbia River .
location
The Astoria Bridge is the last bridge before the Columbia River flows into the Pacific, about 20 km away . It was the missing link to make US Route 101 passable along the west coast of the USA between Olympia in the north and Los Angeles in the south. The southern end of the bridge is in Astoria (Oregon) , the other at Point Ellice , a mountain ledge near the settlement Megler , where the jetty for the ferry to Astoria used to be operated.
At this point the river is around 6 km wide, but mostly flat. The 12.19 m (40 ft ) deep and narrow fairway for the ocean- going ships to Portland runs directly in front of the Astoria site; Beyond it are the Desdemona Sands , a sandbank that extends beyond the middle of the river and sometimes dries out at low tide . In front of the northern bank there are changeable fairways with somewhat deeper water that smaller ships can navigate.
description
Due to these local conditions, the bridge directly on the bank of Astoria had to have the clearance height of 60 m required for the ships and a sufficiently wide opening, while a long section in the middle of the river could be crossed at a low height. Only at the northern end had slightly higher bridges to allow passage on the changing fairways.
The bridge, built between 1962 and 1966, therefore consists of a number of different structures: From the Astoria on the river bank, the access to the large truss bridge rises , under whose main opening the navigation channel runs. Then the roadway is led down over four lattice girders and four concrete bridge fields to a 3.4 km long concrete bridge consisting of 140 fields just above the river. At its end, the road climbs over 8 concrete fields to the steel bridge in front of the northern bank, which consists of 7 truss girders with curved upper chords. A short girder bridge finally creates the connection with the bank.
The bridge has two lanes and two narrow bike lanes, separated only by white lines for the occasional cyclist on long tours. Pedestrians are not allowed on the bridge, except once a year for a large running event.
The bridge had paid for itself through toll revenue by the end of 1993 and has been toll-free since then.
Technical details
The access to the bridge branches in Astoria about 360 m west of the bridge from the main road in a northerly direction, and then describes a 270 ° left-curve, at first on a ramp, then m on a 562 (1,845 ft) long slope bridge of reinforced concrete , to continue to climb above the main road along a mountain slope. Another curve towards the river completes the 360 ° circle and leads over a 94.5 m long truss to the actual bridge.
The truss construction of the main bridge has the appearance of a cantilever bridge , but at 751 m (2,464 ft) it is the longest continuous beam in North America. It is supported by two steel scaffolding pillars on either side of the main opening and one concrete pillar at each end. The pillar spacing of the main opening is 375.5 m (1232 ft), that of the side openings is 187.8 m (616 ft). The scaffolding pillars stand on concrete foundations, which are protected from collisions by ships by ship deflectors in the form of honeycomb-shaped sheet piling at a distance of 4 to 6 m from the foundations.
Four bridge fields with underlying trusses and pillar axis spacings of 108.2 m (355 ft) as well as four T-beam fields made of concrete with pillar axis spacings of 45.7 m (150 ft) form the slope, to which the 140 each 24.4 m (80 ft) long T-beam fields of the low part of the bridge over the shallower water.
The ascent in the north takes place over 8 concrete fields, each 45.7 m (150 ft) long, the subsequent 7 truss girders have pillar spacing of 106.7 m (350 ft). A 45.7 m (150 ft) long steel girder bridge forms the end.
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Web links
Individual evidence
- ↑ a b Astoria-Megler Bridge on Columbiariverimages.com
- ↑ The Astoria Bridge ( Memento of the original from November 20, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. on travelastoria.com
- ↑ See GeoHack: MapTech. Nautical and topographic maps
- ↑ Great Columbia Crossing
- ↑ Leonardo Fernández Troyano: Bridge Engineering. A global perspective. Colegio de Ingenieros de Caminos, Canales y Puentes, Thomas Telford 2003, ISBN 0-7277-3215-3 , p. 405
- ↑ The Astoria Bridge had the longest continuous beam in the world until it was surpassed by the Ikitsuki Bridge in Japan in 1991 .
- ↑ The various sources provide slightly different information.
- ↑ Astoria-Megler Bridge on Bridgehunter.com
- ^ Columbia River (Astoria) Bridge
- ↑ Marcel Prade: Les grands ponts du monde . Deuxième partie, Hors d'Europe. Brissaud à Poitiers, ISBN 2-902170-68-8 , p. 156
