Retractable bridge on:
[Wikipedia]
[Google]
[Amazon]
A retractable bridge is a type of 
Retractable bridges date back to medieval times. Due to the large dedicated area required for this type of bridge, this design is not common. A retractable design may be considered when the maximum horizontal clearance is required (for example, over a canal).
Two remaining examples exist in New York City: the Carroll Street Bridge (built 1889) in
Carroll Street Bridge history at bridgesnyc.com
{{Bridge footer Bridges by structural type Moveable bridges
moveable bridge
A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. In American English, the term is synonymous with , and the latter is the common term, but drawbridge can be limited to the narrower, historical ...
in which the deck can be rolled or slid backwards to open a gap while traffic crosses, usually a ship on a waterway. This type is sometimes referred to as a thrust bridge.
Retractable bridges date back to medieval times. Due to the large dedicated area required for this type of bridge, this design is not common. A retractable design may be considered when the maximum horizontal clearance is required (for example, over a canal).
Two remaining examples exist in New York City: the Carroll Street Bridge (built 1889) in Brooklyn
Brooklyn () is a borough of New York City, coextensive with Kings County, in the U.S. state of New York (state), New York. Kings County is the most populous Administrative divisions of New York (state)#County, county in the State of New York, ...
, and the Borden Avenue Bridge in Queens
Queens is a borough of New York City, coextensive with Queens County, in the U.S. state of New York. Located on Long Island, it is the largest New York City borough by area. It is bordered by the borough of Brooklyn at the western tip of Long ...
. A recent example can be found at Queen Alexandra Dock in Cardiff
Cardiff (; cy, Caerdydd ) is the capital city, capital and List of urban areas in the United Kingdom, largest city of Wales. It forms a Principal areas of Wales, principal area, officially known as the City and County of Cardiff ( cy, Dinas a ...
, Wales
Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
, where the bridge is jacked upwards before being rolled on wheels. Helix Bridge at Paddington Basin
Paddington Basin is the name given to a long canal basin, and its surrounding area, in Paddington, London.
The basin commences 500 m south of the junction known as Little Venice, of the Regent's Canal and the Paddington Arm of the Grand U ...
in London is a more unusual example of the type, consisting of a glass shell supported in a helical steel frame, which rotates as it retracts. The Summer Street Bridge
Summer is the hottest of the four temperate seasons, occurring after spring and before autumn. At or centred on the summer solstice, the earliest sunrise and latest sunset occurs, daylight hours are longest and dark hours are shortest, with ...
over Fort Point Channel
Fort Point Channel is a maritime channel separating South Boston from downtown Boston, Massachusetts, feeding into Boston Harbor. The south part of it has been gradually filled in for use by the South Bay rail yard and several highways (specif ...
in Boston
Boston (), officially the City of Boston, is the capital city, state capital and List of municipalities in Massachusetts, most populous city of the Commonwealth (U.S. state), Commonwealth of Massachusetts, as well as the cultural and financ ...
is a variant type called a retractile bridge. This bridge is oriented northwest–southeast, with the northwest-bound lanes of traffic retracting diagonally to the north, and the southeast-bound lanes retracting diagonally to the west.
Some retractable bridges are also floating bridges, such as the Hood Canal Bridge. Two other floating bridges in Washington state used to have retractable spans but were replaced with new floating bridges without retractable spans: the Evergreen Point Floating Bridge
The Evergreen Point Floating Bridge, also known as the 520 Bridge and officially the Governor Albert D. Rosellini Bridge, carries Washington State Route 520 across Lake Washington from Seattle to its eastern suburbs. The floating span is the ...
(replaced in 2016) and Lacey V. Murrow Memorial Bridge (replaced after it accidentally sank in 1990). This design is popular in Guyana, which has the Demerara Harbour Bridge and the Berbice Bridge.
Historical examples of designs for retractable bridges include those by Leonardo da Vinci
Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, Drawing, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially re ...
and Agostino Ramelli
Agostino Ramelli (1531–ca. 1610) was an Italian engineer best known for writing and illustrating the book of engineering designs ''Le diverse et artificiose machine del Capitano Agostino Ramelli'', which contains, among others, his desi ...
.
In the Netherlands
)
, anthem = ( en, "William of Nassau")
, image_map =
, map_caption =
, subdivision_type = Sovereign state
, subdivision_name = Kingdom of the Netherlands
, established_title = Before independence
, established_date = Spanish Netherl ...
, especially in the province of North Holland, a vlotbrug Vlotbrug (plural, nl, vlotbruggen) translates from Dutch into English as "float bridge". In its broadest sense, it includes pontoon bridges. In a narrower sense, it includes floating swing bridges which pivot either centrally or from one or both ...
is a design of retractable bridge across a canal
Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation) or for conveyancing water transport vehicles (e.g. water taxi). They carry free, calm surface fl ...
in which the roadway floats and can be retracted under fixed structures on the canal banks.
See also
*Guthrie rolling bridge
A Guthrie rolling bridge was a kind of retractable bridge, an 18th-century version of the drawbridge. It was commonly installed as the access across the narrow steep sided ditches characteristic of the polygonal forts of this era.
Rolling brid ...
* Moveable bridges
A moveable bridge, or movable bridge, is a bridge that moves to allow passage for boats or barges. In American English, the term is synonymous with , and the latter is the common term, but drawbridge can be limited to the narrower, historical d ...
for a list of other movable bridge types
References
External links
Carroll Street Bridge history at bridgesnyc.com
{{Bridge footer Bridges by structural type Moveable bridges