Salmon Bay Bridge, Seattle, USA; a single leaf through truss with an above-deck counterweight

A bascule bridge is a drawbridge with a counterweight that continuously balances the span, or "leaf," throughout the entire upward swing in providing clearance for boat traffic. Bascule is a French term for seesaw and balance, and bascule bridges operate along the same principle. They are the most common type of movable bridge in existence because they open quickly and require relatively little energy to operate. Image File history File links MovableBridge_draw. ... Drawbridge at the fort of Ponta da Bandeira; Lagos, Portugal A drawbridge is a type of movable bridge typically associated with the entrance of a castle, but the term is often used to describe all different types of movable bridges, like bascule bridges and lift bridges. ... A truss bridge is a bridge composed of connected elements (typically straight) which may be stressed from tension, compression, or sometimes both in response to dynamic loads. ... A cantilever bridge is a bridge built using cantilevers: structures that project horizontally into space, supported on only one end. ... A lift bridge over the Erie Canal at Lockport. ... 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. ... Falseworks are temporary structures used in the building of bridges and other arched structures in order to hold the item in place until its building is sufficiently far advanced to support itself. ... Image File history File links Clip of Image:Salmon Bay Bridge-2. ... Image File history File links Clip of Image:Salmon Bay Bridge-2. ... Salmon Bay Bridge from the Ballard Locks The Salmon Bay Bridge is a single-leaf bascule bridge across Seattles Salmon Bay from Interbay to Ballard. ... Drawbridge at the fort of Ponta da Bandeira; Lagos, Portugal A drawbridge is a type of movable bridge typically associated with the entrance of a castle, but the term is often used to describe all different types of movable bridges, like bascule bridges and lift bridges. ... Modern seesaws have springs for safer play. ... A weighing scale (usually just scale in common usage) is a device for measuring the weight of an object. ... A log bridge in the French Alps near Vallorcine. ...

Although the bascule bridge has been in use since ancient times, it was not until the 1850s that engineers developed the ability to move very long, heavy spans quickly enough for practical application. Nikolaevsky Bridge across the Neva in Saint Petersburg was the first large bascule bridge, opened in 1850. Since then, all bridges across the Neva and other major rivers in the city (21 in total) were bascule to facilitate navigation, which prevented the city's inhabitants from traveling across the river at night (this remained so until 2003 when the first cable-stayed bridge across the Neva was opened). // Production of steel revolutionized by invention of the Bessemer process Benjamin Silliman fractionates petroleum by distillation for the first time First transatlantic telegraph cable laid First safety elevator installed by Elisha Otis Railroads begin to supplant canals in the United States as a primary means of transporting goods. ... Lieutenant Shmidt Bridge The Lieutenant Shmidt Bridge (Russian: ) is the first permanent bridge across the Neva River in Saint Petersburg, Russia. ... The River Neva (Russian: Нева́) is a 74 km-long Russian river flowing from Lake Ladoga (Ладожское Озеро, Ladožskoe Ozero) through the Karelian Isthmus (Карельский Перешеек, Karelskij PereÅ¡eek) and the city of Saint Petersburg (Санкт-Петербург, Sankt-Peterburg) to the Gulf of Finland (Финский Залив, Finskij Zaliv). ... Saint Petersburg (Russian: Санкт-Петербу́рг, English transliteration: Sankt-Peterburg), colloquially known as Питер (transliterated Piter), formerly known as Leningrad (Ленингра́д, 1924–1991) and... 1850 was a common year starting on Tuesday (see link for calendar). ... 2003 (MMIII) was a common year starting on Wednesday of the Gregorian calendar. ... A cable-stayed bridge is a bridge that consists of one or more pillars, with cables supporting the roadbed. ...

Probably the most famous bascule bridge in the world is Tower Bridge across the Thames in London. Originally, Tower Bridge was a hydraulically operated bridge, using steam power from coal-burning boilers to pump river water into six hydraulic accumulators so that power was readily available when required. The water for the boilers was provided by a well. The hydraulic accumulators powered the bascule engines, which raised and lowered the bascules. Today, the bascule mechanism is driven by oil and electricity rather than by water and steam. For the bridge of the same name in California, see Tower Bridge (California). ... Several places exist with the name Thames, and the word is also used as part of several brand and company names Most famous is the River Thames in England, on which the city of London stands Other Thames Rivers There is a Thames River in Canada There is a Thames... This article is about the capital of England and the United Kingdom. ...

Counterweights may be located above the bridge or below the deck of the bridge. There are two common designs of bascule bridge. One is the trunnion bascule design, which is where the bridge rotates around a large axle called a trunnion to raise. This bridge type is sometimes called the 'Chicago bascule' as this type was developed and perfected there and is used for many of that city's river crossings. Joseph Strauss was a key person who worked on improving the trunnion bascule bridge. Another form of bascule bridge is the Scherzer rolling lift. The city of Joliet, Illinois has a number of this structure type. The Scherzer rolling lift bridge essentially rolls or rocks like a simple rocking chair on a track to raise. Nickname: The Windy City, The Second City, Chi Town, City of the Big Shoulders, The 312, The City that Works Motto: Urbs In Horto (Latin: City in a Garden), I Will Location in Chicagoland and Illinois Coordinates: Country United States State Illinois County Cook & DuPage Incorporated March 4, 1837 Government... The city of Joliet is located 40 miles southwest of Chicago. ...

University Bridge, Seattle, USA; a double leaf bascule with counterweights in the piers, commonly called the Chicago type

Image File history File links Clip of Image:University Bridge-1. ... Image File history File links Clip of Image:University Bridge-1. ... University Bridge from the west; part of the Ship Canal Bridge is visible in the top right corner The University Bridge is a double-leaf bascule bridge that carries Eastlake Avenue traffic over Seattles Portage Bay between Eastlake and the University District. ...

Types of bascule bridges

• Scherzer rolling lift bascule bridge [1]
• Rall bascule bridge - patented by Theodore Rall in 1901. [2]

Strauss bascule bridge - patented by Joseph Strauss. [3] Chicago or fixed-trunnion bascule bridge [4] 1901 (MCMI) was a common year starting on Tuesday (link will display calendar) of the Gregorian calendar (or a common year starting on Wednesday of the 13-day-slower Julian calendar). ... Joseph Baermann Strauss (January 9, 1870 - May 16, 1938) was an American engineer and designer. ...

See also

Pegasus_Bridge, a rolling type

• List of bascule bridges
• Moveable bridge for a list of other movable bridge types.

Wikimedia Commons has media related to:

Bascule bridges

Image File history File links Download high resolution version (2288x1712, 613 KB) Please see the file description page for further information. ... Image File history File links Download high resolution version (2288x1712, 613 KB) Please see the file description page for further information. ... Pegasus Bridge before its replacement Pegasus was the name given to a bridge over the Caen canal, near the town of Ouistreham. ... A list of bascule bridges by country: // Australia The Grafton Bridge over the Clarence River showing the Bascule span lifted to let shipping through. ... A moveable bridge is a bridge that moves to allow passage for (usually) boats or barges. ... Image File history File links Commons-logo. ... Wikimedia Commons logo by Reid Beels The Wikimedia Commons (also called Commons or Wikicommons) is a repository of free content images, sound and other multimedia files. ...

External links

• Learn about the movable bridges of Chicago, Illinois. Most of Chicago's bridges are bascule bridges and are of the trunnion type.
• Learn about the movable bridges of Joliet, Illinois. Most of Joliet's bridges are bascule bridges and are of the Scherzer rolling lift type.