A folding bridge is a movable bridge whose deck consists of several hinged segments that fold upwards like a concertina to let vessels pass. Instead of one rigid leaf that tilts, the deck buckles into itself.
It is one of the rarer types of movable bridge. The best-known example is the Hörnbrücke in Kiel, Germany, a footbridge that folds into three parts — one of the few full-scale examples ever built.
How it works
- Hinged segments. The deck is divided into two or more parts, connected to each other by hinges.
- Drive. Hydraulic cylinders or cables pull the hinge points upwards, so the segments buckle in a controlled way.
- Guidance. Rails, pendulum struts or guide rollers keep the bridge folding to the intended pattern rather than deflecting sideways.
Why choose one
- Low height when open. A leaf bridge of comparable length sticks far up into the air when open. A folding bridge stays lower, is visually less dominant, and can be used where height restrictions apply.
- Little length behind the abutment. Unlike a rolling or sliding bridge, no long strip is needed behind the abutment to retract the deck.
- A design statement. Folding bridges are built almost exclusively for pedestrians and cyclists, in places where the movement itself is part of the design.
Drawbacks
- Many hinges. Every hinge is a wear point and a maintenance item. A leaf bridge has one main pivot; a folding bridge has several per side.
- Complex drive and control. More moving parts means more to go wrong.
- Limited span. In practice only suitable for light, short spans; for road traffic over larger widths a bascule, leaf or lift bridge is almost always the more sensible choice.
In the family of movable bridges
| Type | Movement |
|---|---|
| Drawbridge | Leaf tilts, counterweight in a balance beam above the deck |
| Bascule bridge | Leaf tilts, counterweight below the deck |
| Lift bridge | Deck rises horizontally as a whole |
| Swing bridge | Deck rotates about a vertical axis |
| Rolling bridge | Deck rolls or slides horizontally aside |
| Folding bridge | Deck folds upwards in segments |
Related terms
- Drawbridge
- Bascule bridge
- Beam bridge
- Bridge abutment
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