vertical-lift bridge
{{Short description|Type of movable bridge}}
{{Distinguish|table bridge}}
{{BridgeTypePix
|image=MovableBridge lift.gif
|image_title= An animation showing how a vertical-lift bridge operates with vehicular and shipping traffic
|type_name=Vertical-lift bridge|sibling_names=Bascule bridge, swing bridge, folding bridge, retractable bridge
|descendent_names=Submersible bridge, table bridge
|ancestor_names=Truss bridge
|carries=Automobile, pedestrians, truck, light rail, heavy rail|span_range=Short
|material=Steel
|movable=Yes
|design=medium
|falsework=Depends upon degree of prefabrication}}
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.Troyano (2003), p.731 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.Troyano (2003), p.732
Examples
Gallery of images
Image: Weeks 533 under Wards Is Bridge jeh.jpg|The Wards Island Bridge in New York City over the Harlem River
Image:Hefbrug over de Gouwe bij Alphen aan den Rijn.jpg|One of the vertical-lift bridges over the Gouwe River, built in 1930
Image:Asb-bridge.jpg|ASB Bridge in Kansas City, Missouri
Image: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
File: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{{cite book |last=Wood Wortman |first=Sharon |author2=Wortman, Ed |title=The Portland Bridge Book |edition=3rd |publisher=Urban Adventure Press |year=2006 | page=68 |isbn= 0-9787365-1-6 }}
File:Welland Canal Bridge 21-Clarence St. Bridge - Port Colborne-Ontario-20220317.jpg|Clarence St. Bridge in Port Colborne, Ontario
File:Ponto do Guaíba Aérea.jpg|Guaiba Bridge, which crosses Lake Guaíba, in Porto Alegre, Brazil
File:ErieCanalExchangeSt1.jpg|A lift bridge over the Erie Canal at Lockport, New York
File:ErieCanalExchangeStBr2.jpg|A lift bridge, elevated at both ends
File:ErieCanal.jpg|A lift bridge near its upward position, pedestrians may cross when it is raised by using stairways
File:2021 Nowa Sól bridge.jpg|Small lift bridge in Nowa Sól, Poland
File:Portage Lake Lift Bridge 2020-08-31.jpg|Portage Lake Lift Bridge linking Houghton, Michigan to Hancock, Michigan
File:VR Sr1 3015 Kuopio Drawbridge.jpg|An Sr1 locomotive pulling lumber across a lift bridge north of Kuopio railway station in Finland
See also
- 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
References
{{Reflist}}
=Bibliography=
{{Refbegin}}
- {{cite book
|author=Leonardo Fernandez Troyano
|title=Bridge Engineering: A Global Perspective
|publisher=Thomas Telford Publishing
|year=2003
|isbn=978-0-7277-3215-6}}
{{Refend}}
External links
- {{Commons category-inline|Lift bridges|Vertical-lift bridges}}
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