A swing bridge is a movable bridge that can be rotated horizontally around a vertical axis. It has as its primary structural support a vertical locating pin and support ring, usually at or near to its center of gravity, about which the swing span can then pivot horizontally as shown in the animated illustration to the right.
I Street swing Bridge span turned to allow a boat to pass Sacramento California
BNSF Railroad Bridge 9.6 across the Columbia River in Portland, Oregon, showing the swing-span section turning.
An example of how small swing bridges like this one may be pivoted only at one end, but that does require substantial underground structure to support the pivot. Victoria & Alfred Waterfront, Cape Town.
El Ferdan Railway Bridge in Egypt; the longest swing bridge in the world, runs from the east of the Suez Canal to the west into Sinai. It is left open most of the time to allow sailing ships to pass in the canal, only closing during the passage of trains.
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 to only a specific type of moveable bridge often found in castles.
Madison Street Bridge, a bascule bridge over the Chicago River in Chicago, IL
The Rode Brug (Red Bridge) across the Vecht river in Utrecht, Netherlands
The Marine Parkway–Gil Hodges Memorial Bridge in New York City
