Bascule bridge

A bascule bridge, also called bascule bridge is a moveable bridge, the other roads - often shipping lanes - crosses, only occasionally require greater headroom. The movable structural member ( the flap ) is mounted rotatably about a horizontal axis and situated under the fixed bridge section with rear rods balanced. The bascule bridge is thus easier to move than the drawbridge, as only the frictional resistance of the engine has to be overcome (eg, hand winch and pull chain or rope ).

Types

Dutch bridges

Dutch bridges are known with its high mounted counterweight, as immortalized eg van Gogh in some images, such as the Langlois Bridge near Arles ( built 1820-1830 ). Another wooden bascule bridge of this type in the 19th century, the still operating at Greifswald Wieck bridge ( built in 1887 ).

The longest bascule bridge in Germany is the Jann -Berghaus Bridge at idle with a total length of 464 m. The largest bascule bridge is a span of 106 m in the port of Barcelona.

Faltbrücken

In Chicago there is a bascule bridge of 20 m passage width. In order not to make the flap too cumbersome, they fold together when sitting up. That is why it is called such a bridge type folding bridge. In Kiel, performs a three- field bascule bridge spanning the horn.

Swing or Wippbrücken

Shows another bridge type flaps are arcuately formed according to the bearings. The flaps rotate during the erection process is not modeled after the typical bascule bridges around an axis, but circulate the segment of a circle onto a horizontal path, being guided through racks. Thus, a better distribution of forces and a faster operation is effected. This bridge type is called a swing or Wippbrücke.

An over access to bridgehead high-lying counterweight center of gravity can in the ( or expedient: near ) the axis of rotation be set so that the force for the opening and closing of the folding arm only its rolling friction on the racks (plus or minus a small torque the engagement pressure always puts on only one side of the tooth flanks ) must overcome.

The American engineer William Donald Scherzer developed a special design in which the drive attaches to the pivot point of the system and these shifts horizontally. Well-known examples of this construction are Pegasus Bridge and Pamban ( railway ) bridge.

Pictures

Brick grave bridge in Stralsund

Tower Bridge in London

Erasmus bridge in Rotterdam

Conversion of a decommissioned Bascule Bridge

A disused bascule bridge Pont de la basculant Seyne- sur -Mer in La Seyne -sur -Mer was permanently folded and transformed into a lookout tower.