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Suspension bridge

A suspension bridge is a bridge whose deck is hung beneath one or more main cables supported by towers and anchored at each end.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

A suspension bridge is a bridge whose deck is hung beneath one or more main cables supported by towers and anchored at each end. It is designed to carry loads through tension in the cables and compression in the towers, allowing very long spans. Modern suspension bridges became established in the early 19th century and are often used for major road crossings.

Design and structure

A suspension bridge uses towers, main cables, vertical suspenders, anchorages, and a deck. The deck is supported from above, and the system is arranged so the cables work mainly in tension while the towers carry compression.

How it works

Loads from traffic and the deck are transferred to the suspenders, then to the main cables, towers, and anchorages. This structural arrangement makes long spans possible with relatively few supports in the water or on the ground.

History

While earlier suspension-like bridges existed, the modern suspension bridge emerged in the early 19th century. Later advances in steel cable manufacture and structural engineering made very long spans practical.

Uses and significance

Suspension bridges are especially useful where a long clear span is needed, such as over large rivers, bays, or straits. They are also known for their architectural prominence and engineering importance.

Key facts

  • The deck hangs below curved main cables rather than resting on piers along the full span.
  • Vertical suspenders transfer the deck load to the main cables.
  • The main cables are anchored at both ends of the bridge and pass over towers.
  • Suspension bridges can span longer distances than most other bridge types.
  • They are widely used for major vehicle crossings and are often visually distinctive.
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Canadian context

Suspension bridges are relevant to Canadian infrastructure because they are used for major crossings in cities and regions with wide waterways, valleys, or harbour approaches.

Frequently asked questions

What is a suspension bridge?
A suspension bridge is a bridge whose deck is hung from main cables supported by towers and anchored at both ends.
How does a suspension bridge support weight?
The deck load passes through vertical suspenders to the main cables, which transfer forces to the towers and anchorages.
Why are suspension bridges used for long spans?
Their cable-and-tower system can carry loads efficiently over large distances with few intermediate supports.
When did modern suspension bridges develop?
The modern form developed in the early 19th century.
What are the main parts of a suspension bridge?
Main cables, towers, vertical suspenders, anchorages, and the deck are the main parts.

References

  1. Wikipedia — https://en.wikipedia.org/wiki/Suspension_bridge
    Supports: Basic definition, historical note on early modern examples, and general structure.
  2. Encyclopaedia Britannica — https://www.britannica.com/technology/suspension-bridge
    Supports: Definition, structural mechanics, long-span capability, and general characteristics.
  3. Merriam-Webster — https://www.merriam-webster.com/dictionary/suspension%20bridge
    Supports: Dictionary definition describing roadway suspended from cables over towers.