Queen post
Interior structure of a covered bridge that uses a queen-post structure | |
Ancestor | Truss bridge |
---|---|
Related | None |
Descendant | None |
Carries | Pedestrians, livestock, vehicles |
Span range | short to medium |
Material | wood planks |
Movable | No |
Design effort | medium |
Falsework required | Sometimes |
A queen post is a tension member in a truss that can span longer openings than a king post truss. A king post uses one central supporting post, whereas the queen post truss uses two.[1] Even though it is a tension member, rather than a compression member, they are commonly still called a post. A queen post is often confused with a queen strut, one of two compression members in roof framing which do not form a truss in the engineering sense.[2]
Architecture
A queen-post bridge has two uprights, placed about one-third of the way from each end of the truss. They are connected across the top by a beam and use a diagonal brace between the outer edges. The central square between the two verticals was either unbraced on shorter spans, or had diagonal braces from the bottom of each queen post to the center of the upper cord. The deck is supported by a king post, which is held up by a triangular truss.[3]
An alternative truss construction uses a pair of cross beams between the queen posts, forming an X. This is then considered a Warren truss.
See also
References
- ↑ Gopi, Satheesh. Basic civil engineering. New Delhi: Dorling Kindersley (India) Pvt. Ltd., 2010. 155. Print. ISBN 8131729885
- ↑ "Timber Framing for Beginners: VI. Glossary of Terms" Timber Framing Vol. 68 June 2003. 12. http://tfguild.businesscatalyst.com/downloads/publications/Glossary-of-Timber-Framing-Terms.pdf
- ↑ American Barns and Covered Bridges, Eric Sloane, Wilfred Funk, Inc. New York, New York; 1954, pg 96-97