The Golden Gate and George Washington bridges are two iconic American examples of suspension bridges, but the longest one in the world is Japan's Akashi Kaikyo Bridge, which spans 6,432 feet. One of the world's oldest engineering forms, the suspension bridge is not suitable for every situation.
The area spanned by a suspension bridge is very long in proportion to the amount of materials required to construct bridges.
Built over waterways, suspension bridges can be built high, allowing the passage of tall ships unhindered by the bridge. The Golden Gate bridge has a clearance of 220 feet over the waters of San Francisco Bay at high tide.
During construction, temporary central supports do not need to be built, and access to the construction is not required from beneath. This means busy roadways and waterways do not need to be disrupted.
Suspension bridges are flexible, which is an advantage until conditions become severe. Instability in extremely turbulent conditions or during strong earthquakes may require temporary closure. In 1940, high winds caused the Tacoma Narrows bridge, near Seattle, Washington, to collapse.
When built in soft ground, suspension bridges require extensive and expensive foundation work to combat the effects of the heavy load on foundation towers.
Flexibility also becomes a disadvantage when heavy, concentrated loads are involved. Suspension bridges are not generally used for regional rail crossings that carry maximum weight loads, which adds dangerous stress to the structure.