Star.pngStar.pngStar grey.pngStar grey.pngStar grey.png

Moving Bridges

From Roader's Digest: The SABRE Wiki
Jump to navigation Jump to search

Moving Bridges are those which can be moved to allow a clear shipping lane on a busy river or estuary. They are particularly common, in small scale, on the canal network, but also appear in much grander designs on many of our major rivers.

There are four main designs of bridges that can move, some of which can be built in a very basic or a very elaborate manner. The Transporter Bridges, on the other hand, are always very substantial structures!

Lifting Bridges

Main Article: Lifting Bridges

Whilst the Lifting Bridge is in essence a very basic proposition, used in medieval castles in the form of a Drawbridge, this group also includes the much more complex vertical lift bridge, where the whole road deck is lifted vertically clear of the river between two tall towers. The traditional lifting bridge was once common on the canal network but most have either been replaced with high level or swing bridges, or simply sealed up.

Bascule Bridges

Main Article: Bascule Bridges

A particular type of Lifting Bridge, using a counterweight to balance the road deck as it lifts, the most famous Bascule Bridge is probably Tower Bridge in London.

Swing Bridges

Main Article: Swing Bridges

The Swing Bridge is also a very simple structure, where the road deck is swung in the horizontal plane out of the way of the river. Sometimes this is done from a pivot on one river, or canal bank, as at the Caledonian Canal Swing Bridges in Scotland. Other swing bridges, such as the Kincardine Bridge across the Forth (now sealed) swing from a pivot in the middle of the river, so allowing two shipping channels to open simultaneously.

Transporter Bridges

Main Article: Transporter Bridges

The final, and rarest of the common moving bridge designs is the Transporter Bridge. Only 4 seem to have been completed in the British Isles, and perhaps less than 50 worldwide. They use a cradle suspended from a high level span to act as a ferry back and forth across the channel, but with the benefits of not having to fight the tides or currents.





Moving Bridges
Crossings
Miscellaneous
Bridge Types
Static BridgesArch Bridges • Bowstring Bridges • Cable Stayed Bridges • Cantilever Bridges • Concrete Bridges • Dam Bridges • Early Bridges • Girder Bridges • Iron Arch Bridges • Packhorse Bridges • Suspension Bridges • Trestle Bridges • Truss Bridges • Culverts
Moving BridgesBascule Bridges • Lifting Bridges • Swing Bridges • Transporter Bridges


SABRE - The Society for All British and Irish Road Enthusiasts
Discuss - Digest - Discover - Help