Swing bridge
Encyclopedia : S : SW : SWI : Swing bridge
| Swing bridge | |
|---|---|
| |
| At a river crossing | |
| Ancestor | Truss bridge, cantilever bridge |
| Related | Other moving types: Bascule bridge, drawbridge, jetway, lift bridge, tilt bridge |
| Descendant | Gate-swing bridge - see Puente de la Mujer |
| Carries | Automobile, truck, light rail, heavy rail |
| Span range | Short |
| Material | Steel |
| Movable | Yes |
| Design effort | Medium |
| Falsework required | No |
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A swing bridge is a bridge that has as its primary structural support a vertical locating pin and support ring at or near to its center, about which it can then pivot horizontally as shown in the animated illustration below. 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 over a river or canal, for example, allows road 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 approximately 90 degrees horizontally about its pivot point.
Contents
Advantages
- As this type requires no counterweights the complete weight is significantly reduced as compared to other moveable bridges.
- Where sufficient channel is available to have individual 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 movable span as the construction will not impede channel traffic.
Disadvantages
- The central pier forms a hazard to navigation.
- 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 or tension.
- If struck from the water near the edge of the span, it may rotate enough to cause safety problems (cf. Big Bayou Conot train disaster).
Examples
Argentina
- Puente de la Mujer, a uniquely beautiful and dramatic asymmetrical cable-stayed span.
Australia
- old Pyrmont Bridge, Sydney.
Canada
- Little Current Swing Bridge, crossing the North Channel in Little Current, Ontario.
- A swing bridge crosses the Canso Canal in Nova Scotia.
- The Derwent Way Bridge crosses the Annacis Channel of the Fraser River between Queensborough in New Westminster, British Columbia and Annacis Island in Delta, British Columbia.
- The Fraser River Swing Bridge is a rail bridge that crosses the Fraser River between New Westminster and Surrey in British Columbia.
- The Moray Bridge that connects between Richmond, British Columbia to Vancouver International Airport.
Egypt
- The longest swing bridge span is 340 metres, by the El Ferdan Railway Bridge across the Suez Canal.
Germany
- Kaiser Wilhelm Brücke in Wilhelmshaven, built in 1908, with the length of 159m, it was once Europe's biggest swing bridge
Great Britain
- 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.
- 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 swing bridge is adjacent to the Barton Swing Aqueduct - a 234-foot, 800-tonne trough holding some 800 tonnes 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.
- Swing Bridge, River Tyne at Newcastle Upon Tyne. The Tyne swing bridge 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.
- Trowse swing bridge at Norwich. Carries the Electrified Great Eastern Mainline over the River Yare. The only overhead electrified swing bridge in the world.
- Beccles swing bridge - rail
- Bethells Swing Bridge
- Goole swing bridge - rail
- Oulton broad swing bridge
- Reedham swing bridge
- Selby swing bridge - rail
- Somerleyton swing bridge
- Sutton Bridge swing bridge
- Caernarfon swing bridge
Ireland
- Michael Davitt Bridge, Co. Mayo, Ireland
United States
- Air Line Railway Bridge, Middletown, Connecticut
- Bridgeport Swing Bridge, Bridgeport, Alabama (demolished in late 1970s, replaced with new span)
- Bridge No. 1397, Connecticut Route 156 over the Niantic River, East Lyme, Connecticut-Waterford, Connecticut (1921 steel swing bridge)
- Bridge No. 4455, Central Avenue over Lewis Gut, Bridgeport, Connecticut (1924 steel swing bridge)
- Burlington Northern Santa Fe Railroad Bridge crossing the Columbia River, Portland, OR
- *[Google Maps image]
- East Haddam Swing Bridge, Connecticut Route 82 over the Connecticut River, East Haddam, Connecticut (1913)
- Figure Eight Island Bridge, North of Wilmington, NC
- Mathers Bridge, Connecting Merritt Island, Florida to Indian Harbour Beach, Florida across the Banana River
- New Richmond Swing Bridge, near Fennville, Michigan
- North Fork New River Bridge, Fort Lauderdale, Florida
- Northern Avenue Bridge over Fort Point Channel in Boston, Massachusetts (1908 steel truss)
- Pennsylvania Railroad's Shellpot Branch over Christina River in Wilmington, Delaware (original two-track bridge replaced with a single track bridge in 2003)
- Pennsylvania Railroad's South Philadelphia Branch over Schyulkill River
- Saugatuck River Bridge (Bridge No. 1349), Connecticut Route 136 over the Saugatuck River, Westport, Connecticut (1884 iron-truss swing bridge)
- Spokane Street Bridge over the Duwamish Waterway in Seattle, Washington (1991 reinforced concrete double swing span)
- St. Joseph Swing Bridge over the St. Joseph River, St. Joseph, Michigan (1904)
- Surf City Bridge Surf City, NC
- Willis Avenue Bridge, New York City
See also
- Movable bridge for a list of other movable bridge types
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