Thursday, December 8, 2011

RE: seaint Digest for 7 Dec 2011

RE: out of plane bracing for wood truss bottom chords.

Per TPI 1-2007, the gypsum board is sufficient bracing for the bottom chords as earlier noted. The bottom chord bracing over the shear wall could be integrated with the bottom chord bracing required (suggested) by BCSI-B3 - Building Component Safety Information per WTCA & TPI

Palmer S. Tingey, P.E.
Citrus Heights, Ca. 95610

From: "Jeff Hedman" <>
To: <>
Subject: Interior wood shear wall lateral bracing

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I have a small, wood framed commercial building that has an interior shear
wall (10'-0" tall) that is parallel with a roof truss and directly
underneath it. I have a plan reviewer that is asking for lateral bracing on
top of the wall, similar to gable end wall bracing. We usually have not
provided this for short, wood framed interior walls. Our reason being that
the lateral load at the top of the wall is only 5 psf*10 ft/2 = 25 plf.
Very low loads. The truss manufacturer states that the truss must be braced
with purlins at some spacing or directly applied ceiling in order to keep
the trusses plumb. We are in a seismic design category D, so we generally
do not rely on sheetrock for anything. However, if this is enough bracing
for the trusses to stay plumb, we have generally considered the truss
braced. Since our wall is attached to the truss it is also braced. What
does everyone else do? All I know at this point is over the past 12 years,
I have never seen this type of lateral bracing in construction, nor have I
been asked for it on commercial buildings that we have done in the past.
Perhaps this is a short coming of local construction practices. For masonry
or concrete shear walls and moment frames we require bracing. My question
is specifically for short wood framed shear walls. If it should be there, I
have no problem with requiring it, but I don't want to back down on this if
it is not required.


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