Simple suspension bridge
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| Simple suspension bridge | |
|---|---|
 |
|
| Capilano Suspension Bridge | |
| Ancestor | Inca rope bridge |
| Related | None |
| Descendant | Suspension bridge |
| Carries | Pedestrians, livestock |
| Span range | short to medium |
| Material | Steel wire rope, appropriate decking material |
| Movable | No |
| Design effort | low |
| Falsework required | No |
A simple suspension bridge is an early bridge type and is still formed from native materials, chiefly grass rope, in some areas of South America. These rope bridges must of course be periodically renewed owing to the limited lifetime of the materials, and rope components are made and contributed by families as contributions to a community endeavor. A more permanent variation, suitable for pedestrian and sometimes equestrian use, may be made from simple wire rope. In such bridges, the roadbed of the bridge will follow the downward and upward arc of the load bearing cables, with additional light ropes at a higher level used to form handholds. Owing to practical limitation in the grade and the response to dynamic loads of the bridge deck this type is quite restricted in its load carrying capacity relative to its span. To walk a lighter bridge of this type at a reasonable pace requires a particular gliding step, as the more normal walking step will induce traveling waves that can cause the traveler to pitch (uncomfortably) up and down or side-to-side. Such a bridge may be stabilized by additional cables that do not bear the primary structural or live loads and so may be relatively light. These also add stability in wind. In the bridge shown at upper right the primary supports form the handrails with the deck suspended below. This makes for more motion side-to-side in the walkway than when the primary supports are at deck level.
[edit] See also
- Inca rope bridge for the first bridges of this type
- Stressed ribbon bridge for a modern interpretation of this type, suitable for vehicle traffic
