Vertical lift bridge

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Vertical lift bridge
Ancestor Truss bridge,
Related Bascule bridge, swing bridge, folding bridge, retractable bridge
Descendant Submersible bridge, table bridge
Carries Automobile, pedestrians, truck, light rail, heavy rail
Span range Short
Material Steel
Movable Yes
Design effort medium
Falsework required Depends upon degree of prefabrication

A vertical lift bridge or 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 bridge. Generally speaking they cost less to build for longer moveable spans [1]. 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 more than 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.

Although most vertical lift bridges use towers each with counterweights, some use hydraulic jacks located below the deck. An example is the 16m span bridge at St Paul avenue in Milwaukee [2] (see also table bridges). Another design used balance beams to lift the deck, with pivoting bascules located on the top of the lift towers [3]. An example of this kind was built at La Salle in Illinois, USA.

The biggest disadvantage to the vertical lift bridge is the height restriction that results from the deck being above the passageway.


Contents

[edit] Examples

[edit] Canada

Pretoria Bridge
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Pretoria Bridge
  • Bridges 5 (Glendale Avenue Bridge), 11 (Allanburg Bridge) and 21 (Clarence Street Bridge) on the Welland Canal, all built during the late 1920s as part of the Fourth Canal expansion project (1913-1932). In addition, there are also Bridges 13 (Main Street Bridge), 17 (Dain City Railway Bridge) and 18 (Forks Road Bridge) on the Welland Recreational Waterway (a former channel of the Welland Canal). However, these bridges have not been operational since 1973. Bridges 13 and 18 have had their counterweights removed while the machinery for Bridge 17 has been dismantled. In addition, Bridge 18 no longer possesses its towers; they were removed for ease of maintenance.
  • Pretoria Bridge over the Rideau Canal in Ottawa, Ontario
  • Selkirk Lift Bridge over the Red River in Selkirk, Manitoba
  • Victoria Bridge over the St. Lawrence River connecting St. Lambert and Montreal, Quebec.

[edit] United States

ASB Bridge in Kansas City, Missouri
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ASB Bridge in Kansas City, Missouri

[edit] France

  • Pont de recouvrance - Over the Penfeld in Brest giving access to the military arsenal.

[edit] United Kingdom

[edit] See also


[edit] References

  1. ^ Troyano, Leonardo Fernandez: "Bridge Engineering: A Global Perspective", Thomas Telford Publishing, 2003, p. 731
  2. ^ op. cit., p. 729
  3. ^ op. cit., p. 732