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Re: Live Load Reduction & Partitions

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Richard,

I believe there was a discussion on this issue within the last year or so,
so you may also want to check the archives.

Having said that, the IBC does seem to require partitions "in office
buildings and in other buildings where partition locations are subject to
change..." to be part of the live loads.  This has been how I have treated
partition loads my entire career (nominally as part of the live load).  It
has also been part of the BOCA requirements since the 1996 BOCA code (the
1993 had this basic section under the Dead Load section).  Now, just to
"muddy" things the 1997 UBC has a similar provision in the Dead Load
section.

So, my practice has been for gravity loading to include the
partition load with the live load.  This makes the most sense for me.  It
is the "worst" case scenario for gravity loading when you are using a
strength design method (i.e. with load factors) and does not affect things
too much when using a working stress method (i.e. no load factors).  I
also do this because paritions can be moved at sometime in the future,
which to me signifies a characteristic of live loads.

As the whether or not to reduce them, that is not to abundantly clear.
Personally, I don't, although the issue becomes somewhat irrelevent since
I tend to like to just use a live load of 100 psf for office buildings
(provides for MUCH more flexibility in the future and by section in the
IBC means that a partition loading is not required since the live load
exceeds 80 psf).

Now, if you want to get literal, you can find something to support the
idea that the partition load should not be reduced.  The first statement
of section 1607.9 (which is the section that deals with live load
reduction) states:

"The minimum uniformly distributed live loads, Lo, in Table 1607.1 are
permitted to be reduced according to the following provisions."

The section then goes on the provide two alternate methods to reduce the
live loads (one that came by way of the BOCA and others and the alternate
by way fo the UBC).  The points is that if read literally, the only live
loads that are permitted to be reduced are those from table 1607.1.  And
that table DOES NOT include the provisions for including partition loads
as part of the live load.  Thus, to me, that would mean that the portion
of the live load that is due to partitions would _NOT_ get reduced.

Bruce does bring up something else to consider...where would parition
loads be considered for seismic?  But, then the IBC addresses this in
section 1616.4.1 when defining the W term by stating that W is "the total
dead load and other loads listed below:".  One of the "other loads listed
below" is an allowance for partition loads (item #2).  This would imply
(to me at least) that the partition load is _NOT_ part of the total dead
load.  Besides, item #2 of this "definition" then goes on to give specific
requirements for partition loading when doing the seismic design.

Unfortunately, the commentary for ASCE 7-98 does not have a section for
the partition load section (which is within the live load provisions like
the IBC), so we are not able to gain some guidance from them (since to
some degree ASCE 7 currently [and in the past] is generally the basis for
most of the non-seismic load provisions of most model building codes and
will likely become the basis for ALL the loading provisions [chapter 16 in
the IBC] in the future).

HTH,

Scott
Ypsilanti, MI

On Tue, 26 Aug 2003, richard lewis wrote:

> I usually include partition loading in my summation of dead loads.  I
> notice the IBC has partition loading under live loads.  I assume it has
> always been that way and I never noticed.  Because partitions are a live
> load I see no reason for not including them in the live lad reduction
> formulas.  I never did that in the past.  Is that common among most
> engineers to include partition loading in the live load reduction.
> Partition loading is 20 psf which is a large amount if wood studs or
> metal wall framing is used.  It is not unreasonable I guess if masonry
> partitions are used.
>
> Thanks.
>
> Rich
>
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