Burr Truss

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The Burr Arch Truss — or simply Burr Truss or Burr Arch — is a combination of an arch and a multiple kingpost truss design. It was invented in 1804 by Theodore Burr[1], patented on April 3, 1817[2], and used in bridges, usually covered bridges.[3][4]

[edit] Design

The design principle behind the Burr arch truss was that the arch should be capable of holding the entire load on the bridge while the truss was used to keep the bridge rigid. Even though the kingpost truss alone was capable of bearing a load, this was done because it is impossible to evenly balance a dynamic load crossing the bridge between the two parts.[5] The opposite view is also held, based on computer models, that the truss performs the majority of the load bearing and the arch provides the stability [1]. Regardless, the combination of the arch with the truss provides a more stable bridge capable of carrying greater weight than with the either the truss or arch alone.

Example of a Burr Truss - Baumgardener's Covered Bridge in Pennsylvania
Example of a Burr Truss - Baumgardener's Covered Bridge in Pennsylvania

[edit] References

  1. ^ a b The Burr Truss. Truss Styles of Covered Bridges. New York State Covered Bridge Society (2006-01). Retrieved on 2006-09-15.
  2. ^ Publication Number: X0002769. Publication Images. United States Patent and Trademark Office. Retrieved on 2006-09-15.
  3. ^ Truss Types. Covered Bridge Truss Types. Ohio Department of Transportation Office of Structural Engineering. Retrieved on 2006-09-15.
  4. ^ Truss Types. The Theodore Burr Covered Bridge Society of PA, Inc. Retrieved on 2006-07-28.
  5. ^ Calvert, J. B. (2000-10-23). The Burr Truss. Retrieved on 2006-07-28.
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