This animation shows the movement of a double-leaf bascule.
|Ancestor||Drawbridge, Plate girder bridge, cantilever bridge|
|Related||Lift bridge, swing bridge|
|Carries||Pedestrian, bicycle, automobile, truck, light rail, heavy rail|
|Falsework required||Site and prefabrication specific|
A bascule bridge (also referred to as a drawbridge or a lifting bridge) is a moveable bridge with a counterweight that continuously balances a span, or leaf, throughout its upward swing to provide clearance for boat traffic. It may be single- or double-leafed.
The name comes from the French term for balance scale, which employs the same principle. Bascule bridges are the most common type of movable span because they open quickly and require relatively little energy to operate, while providing the possibility for unlimited vertical clearance for marine traffic.
Bascule bridges have been in use since ancient times. However, it was not until the adoption of steam power in the 1850s that very long, heavy spans could be moved quickly enough for practical application.
There are three types of bascule bridge designs,and counterweights required to balance a bascule's span may be located either above or below the bridge deck.
The fixed-trunnion (sometimes a "Chicago" bascule) rotates around a large axle that raises the span(s). The Chicago bascule name derives from the location where it is widely used, and is a refinement by Joseph Strauss of the fixed-trunnion.
The rolling lift trunnion (sometimes a "Scherzer" rolling lift), raises the span by rolling on a track resembling a rocking chair base. The "Scherzer" rolling lift is a refinement patented in 1893 by the American engineer William Donald Scherzer.
The rarer Rall type combines rolling lift with longitudinal motion on trunnions when opening.It was patented (1901) by Theodor Rall. One of the few surviving examples is the Broadway Bridge (1913), in Portland, Oregon.
Joseph Baermann Strauss was an American structural engineer who revolutionized the design of bascule bridges. He was the chief engineer of the Golden Gate Bridge, a suspension bridge.
A drawbridge or draw-bridge is a type of moveable bridge typically at the entrance to a castle or tower surrounded by a moat. In some forms of English, including American English, the word drawbridge commonly refers to all types of moveable bridges, such as bascule bridges, vertical-lift bridges and swing bridges, but this article concerns the narrower, more historical definition of the term.
The Burnside Bridge is a 1926-built bascule bridge that spans the Willamette River in Portland, Oregon, United States, carrying Burnside Street. It is the second bridge at the same site to carry that name. It was added to the National Register of Historic Places in November 2012.
The Broadway Bridge is a Rall-type bascule bridge spanning the Willamette River in Portland, Oregon, United States, built in 1913. It was Portland's first bascule bridge, and it continues to hold the distinction of being the longest span of its bascule design type in the world. It was added to the National Register of Historic Places in November 2012.
The Mystic River Bascule Bridge is a bascule bridge spanning the Mystic River in Mystic, Connecticut in the United States. It carries vehicle and foot traffic directly into the tourist district of town via 33 ft-wide (10 m) Main Street.
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.
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 drawbridge, and the latter is the common term, but drawbridge can be limited to the narrower, historical definition used in some other forms of English, in which drawbridge refers only to a specific type of moveable bridge.
The North Avenue Bridge can refer to one of three bridges that has carried North Avenue over the North Branch of the Chicago River on the north side of Chicago, Illinois. A center-pier swing bridge built in 1877 was replaced in 1907 by a bascule bridge, allowing river traffic more room for maneuvering in and out of the North Canal, just north of Goose Island.
The Glimmer Glass Bridge is a county owned bridge in Monmouth County, New Jersey, United States. It carries traffic from Brielle Road over the Glimmer Glass, a navigable tidal inlet of the Manasquan River, between Manasquan and Brielle. It has also been on the National Register of Historic Places, since 2008.
The Cortland Street Drawbridge over the Chicago River is the original Chicago-style fixed-trunnion bascule bridge, designed by John Ericson and Edward Wilmann. When it opened in 1902, on Chicago's north side, it was the first such bridge built in the United States. The bridge was a major advance in American movable bridge engineering, and was the prototype for over 50 additional bridges in Chicago alone. The bridge was designated as an ASCE Civil Engineering Landmark in 1981, and a Chicago Landmark in 1991.
Amtrak's Thames River Bridge spans from New London to Groton, Connecticut, United States, crossing Connecticut's Thames River.
The Cherry Street Strauss Trunnion Bascule Bridge is a bascule bridge and Warren truss in Toronto, Ontario, Canada. Located in the industrial Port Lands area, it carries Cherry Street over the Toronto Harbour Ship Channel and opens to allow ships to access the channel and the turning basin beyond. There are two bascule bridges on Cherry Street. The other, smaller bridge, crosses the Keating Channel, while this bridge crosses the Ship Channel.
The Amtrak Old Saybrook – Old Lyme Bridge is the last crossing of the Connecticut River before it reaches Long Island Sound. It is a Truss bridge with a bascule span, allowing boat traffic to go through. Its tracks are owned by Amtrak and used by Northeast Regional, Acela Express, Shore Line East trains traversing the Northeast Corridor. It can be seen from the Raymond E. Baldwin Bridge, as well as from various points on Route 154.
The Crook Point Bascule Bridge is a defunct Scherzer rolling lift railway bridge which spans the Seekonk River, connecting the city of Providence, Rhode Island, to the city of East Providence. Stuck in the open position since its abandonment in 1976, it is known to nearby residents as the "Stuck-Up Bridge" and has become somewhat of a local icon of urban decay.
Niantic River Bridge, also known as Amtrak Bascule Bridge No. 116.74, is a railroad bridge carrying Amtrak's Northeast Corridor line across the Niantic River between East Lyme and Waterford, Connecticut. It is a drawbridge with a bascule-type draw span. A new bridge was constructed in 2012 to replace the former span built in 1907. It opened on September 8, 2012. Related construction work finished in June 2013.
The Grand Street Bridge was a double-leaf deck-girder bascule bridge in Bridgeport, Connecticut, United States, that spanned the Pequonnock River and connected Grand Street and Artic Street. It was one of three movable bridges planned by the City of Bridgeport in 1916 at the request of the War Department during World War I. Construction was completed in 1919, but the delays surrounding the construction went to the Connecticut Supreme Court in case of Edward DeV. Tompkins, Inc. vs. City of Bridgeport, Connecticut. The court ruled in favor of Tompkins and awarded damages equal to the contract. In 1936, the bridge had excessive settling and required the replacement of its southeast pier. As part of the repairs, a new floor and electrical system were installed. In 1965, the floor was replaced with a steel grate on I-beam floor. In 1984, the eastern approach span was replaced and the northwest trunnion post was reconstructed. The bridge was closed in the 1990s and dismantled in 1999.
Eighth Street Bridge is a road bridge over the Passaic River in northeastern New Jersey, United States. Opened in 1915 as a bascule bridge, the bridge was fixed in place in 1977.
William Donald Scherzer was an American engineer and inventor who invented the rolling lift bridge.
A double-beam drawbridge, seesaw or folding bridge is a movable bridge. It opens by rotation about a horizontal axis parallel to the water. Historically, the double-beam drawbridge has emerged from the drawbridge. Unlike a drawbridge, a double-beam drawbridge has counterweights, so that opening requires much less energy.
|Wikimedia Commons has media related to Bascule bridges .|