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RE: Truss bracing

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So, is there some direction, text, etc to determine the requirements for the
strength and stiffness required for the tension chord.  I've been hoping
that something like that would come up in this thread because I have a
situation with a "fish belly" truss, you know the old King Post truss that
shows up in all the old statics books where the top chord is continuous and
horizontal and the bottom chord is discontinuous and pitched two directions.
What would be the bracing requirements for the bottom chord at the
compression web location at the junction of the two bottom chords?

Joseph R. Grill, PE

-----Original Message-----
From: Curt LaCount [mailto:Curt.LaCount(--nospam--at)jacobs.com]
Sent: Friday, December 08, 2000 2:42 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: Truss bracing

Mark,

One important point to consider is the compression web members that are
attached to the tension chord.  These web members are normally designed as
pinned ended and K=1.0.  Unless the tension chord has the strength and
stiffness to provide the out-of-plane restraint required for the K=1.0
effective length factor, then bracing is to be provided for that function.
So in effect, one is not bracing the tension chord, but the compression web
members.

Curt La Count
Jacobs Engineering
Portland, OR



All good input from you folks, thanks. My gut tells me not to say "it's a
tension member, it doesn't need bracing". Would you agree?

Mark