Subject: 3x Member w/Anchorage Forces in Sub-Diaphragm
From: Kevin Kaplan <kevink(--nospam--at)vlmk.com>
Date: Tue, 20 Jun 2000 12:42:30 -0700
If anyone can shed some light to the following code exerpt, it would be
appreciated. Our office has been "discussing" this item for quite some time
UBC Section 1618.104.22.168 Out-of-plane wall anchorage to flexible diaphragms.
Item 5 reads as follows:
5. The strength design forces for wood elements of the wall anchorage
system shall be 0.85 times the force otherwise required by this section and
these wood elements shall have a minimum actual net thickness of 2-1/2".
Our office has been discussing whether this 3x requirement for the wall
anchorage system, requires all of the sub-purlins in the sub-diaphragm to be
3x's, or just the first bay where the anchorage actually occurs.
Furthermore, in cases where a Simpson Tension Tie is anchored below the roof
to the side of the sub-purlin, could the thickness of the member be
considered to be the actual depth of the sub-purlin (5-1/2" for a 2x6
sub-purlin)? This seems to make sense if the code is trying to limit the
potential of splitting of the sub-purlin.
Kevin M. Kaplan, P.E.
Associate / Project Manager
VLMK Consulting Engineers
3933 SW Kelly Avenue
Portland, Oregon 97201-4393
Phone (503) 222 - 4453
Fax (503) 248 - 9263
Mobile (503) 799 - 0814