A suspension bridge is a bridge in which the deck is carried by vertical hangers that hang from two large, sagging main cables. These main cables run over tall towers (pylons) and are firmly anchored into the ground at each end. The suspension bridge can span very long distances and is one of the best-known bridge types in the world.
How it works
The structure of a suspension bridge relies on tensile forces in the cables:
- Main cables — two large cables hang in a curve (catenary) between the pylons
- Pylons — tall towers carry the main cables and lead the force to the foundation
- Hangers — vertical cables connect the main cables to the deck
- Anchorage — at both ends the main cables are anchored in heavy anchor blocks that absorb the enormous tensile force
The deck thus hangs “suspended” beneath the cables, allowing large spans without intermediate supports.
Applications
Suspension bridges are used where long distances must be bridged:
- Wide rivers and straits — where intermediate supports are impossible or undesirable
- Waterways — the clear span lets shipping pass unhindered
- Pedestrian and cycle suspension bridges — a lighter variant, for example over ravines or in parks
Difference from the cable-stayed bridge
A suspension bridge is often confused with a cable-stayed bridge. In a suspension bridge the hangers run from sagging main cables; in a cable-stayed bridge straight stay cables run directly from the pylon to the deck. Both suit large spans, but the way forces are carried differs.
Related terms
- Bridge
- Structure
- Foundation
- Anchor
- Hanging arches
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