Bowstring Truss – Wednesday’s Word Of The Week
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| Bowstring Truss Ready To Ship |
The next type of truss in our “Word of the Week” series is the bowstring truss. This is probably the most efficient long span framing system for glulam. A bowstring truss has a curved top chord (so the building will have a curved “barrel” roof) and a straight bottom chord. Together they look like an archery bow pointed upward, where the bottom chord is the bowstring.
Diagonal web members are added as usual between the chords, although they are primarily active only under unbalanced load cases. Web members and connections can be relatively small. Almost all forces are resisted by the top and bottom chords, and their connection (called the “heel”) is critical to the overall design.
The radius of curvature for the top chord should be equal to the truss span. Bowstring trusses can easily span 80 to 150 feet, and up to 200’+.
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| We Manufactured The Bowstring Trusses For Our Sidney Plant (Late 1950s) |
*Each Wednesday our structural engineer, Rik Vandermeulen, discusses a new term associated with glulam manufacturing. He will do this until we run out of words. If there is a timber or glulam term that you have heard of and want to know more about, let us know in the comments.