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February 21, 2014

Types of pioneered bridge

All bridges can be classified into one of a few categories, based on how the structure supports the load. Pioneered bridges are the same, and most fall into four categories:
  1.  Simple or beam bridge: this is the simplest case, a bridge where the deck itself carries the weight of the structure. This bridge built by Culford School Troop is an example, and most drawbridges function this way in the down position.
  2. A trussed bridge is a structure where the supports are triangulated members. The double lock trestle bridge is one example.
  3. A tied arch bridge uses an arch that hangs above the deck to support the deck. In pioneering, the Banana Bridge uses an arch made from pioneered frames.
  4. Suspension bridges use a structure hanging in pure tension to support the load, either as a separate deck like the Abington Spring Bridge, or by walking directly on the tensile members in a monkey bridge.
  5. Cable stayed bridges (like the Nelson Mandela Bridge in Johannesburg) use a tower or series of towers that support a deck using straight cables. I'm not aware of any pioneered cabel stayed bridges, but I'd love to be proven wrong.
  6. In an arched bridge, an archway forms the deck, or runs under the deck, and supports the load. Ploeg Technieken in Belgium built this bridge supported by arches.
Of these 6 types, types 5 and 6 are pretty rare in pioneering- I can only think of the one arched bridge, and I can't find any cable stayed pioneered bridges. So, before the end of summer (for us down here in the Southern hemisphere) or, while you're waiting for the weather to warm up (for you up there in the Northern hemisphere) , why not give a cable stayed bridge a try?

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