Swingbridge

A swing bridge (or swing span bridge) is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its center of gravity, about which the swing span (turning span) can then pivot horizontally as shown in the animated illustration to the right. Small swing bridges as found over canals may be pivoted only at one end, opening as would a gate, but require substantial underground structure to support the pivot.

In its closed position, a swing bridge carrying a road or railway over a river or canal, for example, allows traffic to cross. When a water vessel needs to pass the bridge, road traffic is stopped (usually by traffic signals and barriers), and then motors rotate the bridge horizontally about its pivot point. The typical swing bridge will rotate approximately 90 degrees, or one-quarter turn; however, a bridge which intersects the navigation channel at an oblique angle may be built to rotate only 45 degrees, or one-eighth turn, in order to clear the channel.

Advantages

*As this type requires no counterweights, the complete weight is significantly reduced as compared to other moveable bridges.
*Where the channel is wide enough for separate traffic directions on each side, the likelihood of vessel-to-vessel collisions is reduced.
*The central support is often mounted upon a berm along the axis of the watercourse, intended to protect the bridge from watercraft collisions when it is opened. This artificial island forms an excellent construction area for building the moveable span, as the construction will not impede traffic.

Disadvantages

* In a symmetrical bridge, the central pier forms a hazard to navigation. Asymmetrical bridges may place the pivot near one side of the channel.
* Where a wide channel is not available, a large portion of the bridge may be over an area that would be easily spanned by other means.
* A wide channel will be reduced by the center pivot and foundation.
* When open, the bridge will have to maintain its own weight as a balanced double cantilever, while when closed and in use for traffic, the live loads will be distributed as in a pair of conventional truss bridges, which may require additional stiffness in some members whose loading will be alternately in compression and tension.
* If struck from the water near the edge of the span, it may rotate enough to cause safety problems (see Big Bayou Canot rail accident).

Examples

Albania

*Buna River Bridge, in Shkodra, Albania.

Argentina

*Puente de la Mujer, an asymmetrical cable-stayed span.

Australia

* Gladesville Bridge, Sydney. Opened 1881, closed 1964 and demolished; had a small swing span on the southern end.
* Pyrmont Bridge, Sydney. Opened 1902. Closed to traffic 1988. Still in use as a pedestrian bridge.
* Glebe Island Bridge, Sydney. Opened 1903. Tramway defunct. Closed to traffic, 1995; supplanted by Anzac Bridge. Still in existence.
* Hay Bridge, Hay, New South Wales. Opened 1873, demolished 1973. Replaced by a fixed concrete bridge.
* Victoria Bridge, Townsville, Queensland. Opened 1889, closed to traffic 1975. Still in use as a foot bridge.
* Sale Swing Bridge, Sale, Victoria. Opened 1883. Closed to traffic in 2002. Restored to full working order in 2006.
* Dunalley Bridge, Dunalley, Tasmania. Still in use.

Belize

* Belize City Swing Bridge, Belize City, Belize. Oldest such bridge in Central America and one of the few manually operated swing bridge in world still in operation. (Restored in the 2000s)

Canada

China

* , across Hai River in Tianjin

Denmark

*Lille Langebro Pedestrian double swing bridge crossing the inner harbour at Copenhagen.

Egypt

* The longest swing bridge span is 340 metres, by the El Ferdan Railway Bridge across the Suez Canal.

France

* Le pont tournant rue Dieu, across the Canal Saint-Martin in Paris, is a distinctive location in the 1938 film ''Hôtel du Nord'', and is featured in the opening shot of the film.

Germany

* Kaiser-Wilhelm-Brücke in Wilhelmshaven, built in 1907, with a length of 159m, it was once Europe's biggest swing bridge.

India

* Garden Reach Road Swing Bridge, for Calcutta Port, Kidderpore, Kolkata
* Poira-Corjuem Bridge, for GSIDC, Corjuem, Goa by Rajdeep Buildcon Pvt. Ltd.

Ireland

* Samuel Beckett Bridge, Dublin
* Seán O'Casey Bridge, Dublin
* Michael Davitt Bridge, County Mayo
* Portumna bridge, between County Galway and County Tipperary

Italy

* Ponte Girevole, Taranto (built in 1958, after an 1887 one of similar design but using different materials) – a very unusual type, with two spans that separate at the bridge's center and pivot sideways from the bridge's outer ends.

Latvia

* Kalpaka Tilts, Liepāja, connecting the city with the former Russian/Soviet port Karosta.

Lithuania

* Chain Bridge, Klaipeda. Built in 1855 and still working today, this is the only swing bridge in Lithuania. When the bridge is turned, boats and yachts can enter the Castle port. Rotation of the bridge is manual; two people can rotate the bridge.

The Netherlands

* The "Abtsewoudsebrug" in Delft, close to the Technische Universiteit Delft, is a bridge of this type.
* There are four bridges of this type in use on the Afsluitdijk (Enclosure dam). They span the waterways that link the shipping lock complexes to the Wadden Sea.
* There is another one on the channel between Ghent (Belgium) and Terneuzen (The Netherlands) at Sas Van Gent.

Many inner cities have swing bridges, since these require less street space than other types of bridges.

New Zealand

* Kopu Bridge, Waihou River, near Thames, New Zealand
(A "swing bridge" in New Zealand refers to a flexible walking track bridge which "swings" as you walk across.)

Panama

* A swing bridge at the Gatun Locks provides the only road passage over the Atlantic side of the Panama Canal. This is a small bridge that swings out from each side. Another larger swing bridge at the Miraflores Locks is on the Pacific side but is rarely used, having been supplanted by the Bridge of the Americas and the Centennial Bridge.

Poland

* A swing bridge at the Giżycko is one of four bridges that cross over the Luczanski Channel. It is one of ten (four still in operation) swing bridges in Poland.

South Africa

* The Clocktower Bridge is a pedestrian swing bridge at the Victoria and Alfred Waterfront in Cape Town.

Ukraine

* Varvarivskyi Bridge over the Southern Bug in Mykolaiv, with Europe's longest span (134 m)

United Kingdom

In the UK, there is a legal definition in current statute as to what is, or is not a 'swing bridge'

* Acton swing bridge – road
* Barmouth Bridge – rail
* Beccles swing bridge – rail
* Bell's Bridge, Glasgow – pedestrian
* Bethells Swing Bridge
* Boothferry swing bridge at Boothferry, Yorkshire (see article for image)
* Caernarfon swing bridge
* Connaught Crossing in London Docklands, built as a low-rising swing bridge to allow marine traffic in the Royal Docks to pass at a place when the proximity of London City Airport meant a higher fixed bridge was not practicable.
* Cross Keys Bridge in Sutton Bridge – carries the A17 road over the River Nene in Lincolnshire
* Folkestone Harbour railway station – railway bridge on the branch line.
* Goole railway swing bridge
* Glasson Dock swing bridge
* Hawarden Railway Bridge – rail (now deactivated).
* Hull, England docks branch bridge – rail
* Kennet and Avon Canal at Tyle Mill Lock, Sulhamstead, Berkshire
* Kincardine Bridge – crossing the Firth of Forth from Falkirk council area to Kincardine-on-Forth, Fife (now deactivated).
* Leeds and Liverpool Canal Has a large number of swing bridges, especially between Bingley and Skipton and Burscough and Liverpool. Many are manually operated, carrying only farm tracks, but a significant number carry road traffic and are mechanised for boater operation.
* Manchester Ship Canal at Latchford, Stockton Heath and Lower Walton in Warrington, and also slightly further west at Moore. Near the eastern end of the canal in Salford, the Barton Road Swing Bridge is adjacent to the Barton Swing Aqueduct – a 234-foot, 800-ton trough holding some 800 tons of water (retained by gates at either end) swings so that it is at right angles to the Bridgewater Canal to allow ships to pass up the Ship Canal.
* Oulton Broad swing bridge – rail
* Reedham Swing Bridge () – rail
* Ross Bridge, Penzance
* Sandwich Toll Bridge (rebuilt 1892)
* Selby swing bridge – rail
* Somerleyton swing bridge
* Trowse Bridge at Norwich. Carries the electrified Great Eastern Main Line over the River Yare. It is the only overhead electrified swing bridge in the country.
* Tyne swing bridge at Newcastle Upon Tyne, which has an 85.7-metre cantilevered span with a central axis of rotation able to move through 90° to allow vessels to pass on either side of it.
* Whitby Swing Bridge over the River Esk at Whitby, North Yorkshire, with two swing leaves (though only one is usually opened).
*Yar Swing Bridge, Yarmouth, Isle of Wight

Kennet & Avon Canal