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A vertical-lift bridge or just lift bridge is a type of movable bridge in which a span rises vertically while remaining parallel with the deck.
The vertical lift offers several benefits over other movable bridges such as the bascule and swing-span bridges. Generally speaking, they cost less to build for longer moveable spans.<ref>Troyano (2003), p.731</ref> The counterweights in a vertical lift are only required to be equal to the weight of the deck, whereas bascule bridge counterweights must weigh several times as much as the span being lifted. As a result, heavier materials can be used in the deck, and so this type of bridge is especially suited for heavy railroad use. The biggest disadvantage to the vertical-lift bridge (in comparison with many other designs) is the height restriction for vessels passing under it, due to the deck remaining suspended above the passageway.
Most vertical-lift bridges use towers, each equipped with counterweights. An example of this kind was built in Portland, Oregon, United States in 1912.
Another design uses balance beams to lift the deck, with pivoting bascules located on the top of the lift towers.<ref>Troyano (2003), p.732</ref>
ExamplesEdit
See List of vertical-lift bridges.
Gallery of imagesEdit
- Weeks 533 under Wards Is Bridge jeh.jpg
The Wards Island Bridge in New York City over the Harlem River
- Hefbrug over de Gouwe bij Alphen aan den Rijn.jpg
One of the vertical-lift bridges over the Gouwe River, built in 1930
- Asb-bridge.jpg
- Arthur Kill Lift Bridge by Dave Frieder.jpg
Arthur Kill Vertical Lift Bridge has the longest lift span of any vertical-lift bridge in the world
- Hawthorne Bridge (Portland, Oregon) from southwest, 2012.jpg
Hawthorne Bridge (in Portland, Oregon, U.S.), built in 1910, the oldest vertical-lift bridge in the United States<ref name = "Wortman">Template:Cite book</ref>
- Welland Canal Bridge 21-Clarence St. Bridge - Port Colborne-Ontario-20220317.jpg
- Ponto do Guaíba Aérea.jpg
Guaiba Bridge, which crosses Lake Guaíba, in Porto Alegre, Brazil
- ErieCanalExchangeSt1.jpg
A lift bridge over the Erie Canal at Lockport, New York
- ErieCanalExchangeStBr2.jpg
A lift bridge, elevated at both ends
- ErieCanal.jpg
A lift bridge near its upward position, pedestrians may cross when it is raised by using stairways
- 2021 Nowa Sól bridge.jpg
Small lift bridge in Nowa Sól, Poland
- Portage Lake Lift Bridge 2020-08-31.jpg
- VR Sr1 3015 Kuopio Drawbridge.jpg
An Sr1 locomotive pulling lumber across a lift bridge north of Kuopio railway station in Finland
See alsoEdit
- Moveable bridges for a list of other movable bridge types
- Submersible bridge for a similar disappearing bridge
- Table bridge for a vertical-lift bridge without visible lifting means