definition
strict definition
drawbridge
A hinged bridge lifted at its free end by chains, cables, or ropes, without a counterweight at the hinge.
A drawbridge is a simple type of openable bridge whose span rises on a hinge when the free end is lifted by chains, cables, or ropes. The opening motion is similar to a bascule bridge, but it operates without counterweights on the hinge.
The lifting connection acts at the free end while the other end turns about a hinge. Chains, cables, and ropes are alternative means of supplying that lift.
The absence of a counterweight at the hinge distinguishes this drawbridge form from the separately defined bascule bridge. The term does not encompass every bridge capable of opening.
Related definitions
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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. -
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.