movable bridge
A bridge of any form which is capable of controlled movement in order to lift or remove its span.
A movable bridge is a bridge which can clear a path under it, or switch its direction, by means of controlled movement around some point or along some axis. Movable bridges can swing around an endpoint or midpoint, can be lifted vertically at one or both ends, or can pivot up at one or both ends.
The opening action is a controlled change in the position or shape of a span. It can provide passage for traffic below or align the bridge with a different route.
Different mechanisms raise, lower, rotate, slide, or fold the crossing. A submersible span moves downward into the water; a fixed bridge temporarily covered by flooding has no corresponding controlled opening action.
movable bridge Photos
More specific definitions
12 sub-definitions-
bascule bridge
A movable bridge with one or two leaves that rise on hinges with assistance from counterweights. -
curling bridge
A movable bridge with a flexible or segmented span which opens by curling vertically. -
drawbridge
A hinged bridge lifted at its free end by chains, cables, or ropes, without a counterweight at the hinge. -
folding bridge
A movable bridge with a segmented span that folds horizontally like an accordion to open the crossing. -
retractable bridge
A movable bridge whose deck opens by sliding back from the channel over or under its approach. -
rolling bascule bridge
A movable bridge whose span rises as large gears roll along a shoreline rack, without a fixed hinge. -
submersible bridge
A movable bridge whose span sinks below water to allow boat traffic to move over it. -
swing bridge
A movable bridge with a span that turns horizontally about a fixed pivot at its center or one end. -
table bridge
A movable bridge whose span is pushed upward from below at both ends, usually by hydraulic pillars. -
tilt bridge
A movable bridge with a curved span that forms an arch when rotated at the ends. -
transporter bridge
A bridge which conveys traffic across its span via gondolas suspended from a high track or cables. -
vertical-lift bridge
A movable bridge whose level span is raised along towers at its ends, usually by counterweighted cables.
Related definitions
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arch bridge
A bridge whose deck is supported from below by one or more arches carrying loads toward their end supports. -
beam bridge
A bridge with a rigid spanning member resting on supports at both ends of each span. -
cable-stayed bridge
A bridge whose deck is supported by tense cables mounted on columns or in the surrounding landscape. -
cantilever bridge
A bridge whose spans project from anchoring piers instead of simply resting on supports at both ends. -
float bridge
A bridge whose span floats on water and is simply anchored to stabilization points. -
suspension bridge
A bridge whose span hangs from main cables anchored at its ends, commonly supported above the span by towers. -
trestle
A bridge or viaduct whose deck is carried by a continuous rigid support framework, often over many small spans. -
truss bridge
A bridge whose span is carried by a connected truss framework with members acting in tension and compression.