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RE: tilt-up concrete walls
- To: <seaint(--nospam--at)seaint.org>
- Subject: RE: tilt-up concrete walls
- From: "Bill Allen, S.E." <T.W.Allen(--nospam--at)cox.net>
- Date: Fri, 4 Feb 2005 15:22:50 -0800
There are two schools of thought here.
Some believe that the stretching of the
chord bars (particularly if they are unbonded for some distance away from the
end of the panel) between the panels negate the distribution according to
I’m not saying which is right or
which is wrong, but I know a lot of people on either side of the fence on this
I think good judgment is required in any
approach when substituting a mathematical model for reality.
T. William (Bill) Allen, S.E. (CA #2607)
V (949) 248-8588
F (949) 209-2509
From: Paul Feather
Sent: Friday, February 04, 2005
Subject: Re: tilt-up concrete
You need to distribute the shear based on relative rigidity
of the wall panels. The continuous chord reinf is also a contributing
drag element for distribution of the diaphragm shear to the panels. Each
panel will have a relative rigidity, and then the individual piers within each
If the panels are "reasonably" different, there is
no valid justification for assuming things will be evenly
distributed. Relative rigidity distribution will be more accurate and
proper. For the even distribution idea to be valid, each panel would have
to be able to deflect independently along the diaphragm length with local
deformation of the diaphragm and the chord.
----- Original Message -----
Sent: Friday, February
04, 2005 11:25 AM
Subject: tilt-up concrete
I have what I think would be an
I have a tilt-up project that I'm working
on. So far, it's going pretty well - but I realized that I wasn't sure
about distributing the in plane shears in the wall panels. The panels are
22' tall with the roof diaphragm at roughly 19' (it varies with
drainage). At the plane of the roof diaphragm the panels are solid (no
major openings) but the openings for the doors (which vary from 10' to 12') are
placed such that each of the wall panels is "reasonably"
different. In other words, the openings are of differing heights and
occur in different locations in each of the panels. From the main
elevation, the openings appear to be centered equally, but when you figure out
where the panel joints are located, the openings are NOT in the same location
for each panel.
I had two thoughts. One was that
since the panels at the height of the diaphragm were solid and each virtually
identical in length, the in plane shear would be distributed equally. The
other thought was that I should really think to distribute the shears based on
the wall widths at the openings.
Obviously the first method would be (much)
simpler but I wasn't sure that the second method would be much more accurate,
if at all. Any advice?
Christopher S. Campbell
O'Connor Freeman & Assoc., Inc.
916.441.5721 fax 916.441.5697
"They're only mad at me because I'm right"