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RE: Fixed File Cabinet - Dead Load or Li

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You might be trying too hard to get this to fit into one category or the
other.  ASCE-7 defines "minimum" load factors.  If you feel comfortable with
the concept of treating it as a known load, but feel 1.2 may be too low, try
1.4.  It is still below 1.6 but higher than 1.2.  You are allowed to modify
the load factors as you see fit provided you are more conservative than
ASCE.

I have used alternate load factors in the past, although they are more
conservative.  I use 2.0 instead of 1.6 for some equipment loadings due to
motion.  Engineering judgment is allowed here...

Jake Watson, P.E.
Salt Lake City, UT

-----Original Message-----
From: Eric Green [mailto:EGreen(--nospam--at)walterpmoore.com]
Sent: Tuesday, July 23, 2002 9:39 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: Fixed File Cabinet - Dead Load or Li


Roger,

The question of LL vs DL seems to me to be one of probability. In a rolling
file cabinet, the maximum load that can ever be placed in the file cabinet
can be well defined (i.e. every cubic inch of file completely full), and I
know exactly how the space will be used (as a file room). If this is used as
the basis for the design, it seems it would be reasonable to define this as
a dead load as opposed to a live load, as it is very unlikely this load will
ever be exceeded in the real world. I do not see much difference between a
rolling file cabinet and a large a/c compressor or air handler (which ASCE
clearly indicates is a dead load).

This differs from normal live loads, such as office loads, where one assumes
50 psf is the most that will be placed on the floor, but this can easily be
exceeded, for example, where someone installs a book case, and it is
reasonably foreseeable that this will occur at some point in the life of the
structure.

The LL argument would be more persuasive to me if one was assuming the files
were only partially full in the analysis. I am assuming they are completely
full.

eric green

-----Original Message-----
From: Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com]
Sent: Tuesday, July 23, 2002 10:13 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: Fixed File Cabinet - Dead Load or Li


Eric,

I believe that you are grasping to justify using low dead load factors.  The
load factors are low based on the theory that *dead loads* are fairly
predictable.  Rolling file cabinet loads are *not* fairly predictable.  In
fact, I would equate them to at least library stack rooms.  (Library stacks
at least have fixed aisles; rolling file cabinets maybe have only one aisle,
and that can be anywhere.)

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

Eric Green's and Scott Maxwell's exchange:

=======================================================

I believe ASCE-7 is referring to "built-in" cranes, not crawler/construction
cranes.

-----Original Message-----
From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
Sent: Tuesday, July 23, 2002 8:59 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: Fixed File Cabinet - Dead Load or Live Load?


Oh, and in your crane analogy, unless the cranes "permanently" attached in
one location (still a difficult "thing" to achieve), the weight of the
crane would be considered a live load not a dead load.  For your typical
construction type crane, the crane will move to a location, do its
"picking" for awhile from that location, then move to a new
location...thus, live load.  For a building bridge or monorail crane, it
is DEFINITELY a live load since the bridge/hoist location will change
in order to pick something up (which could be a different locations) and
then move it to another location.  About the only thing in a bridge crane
system that could even be argued to be dead load would be the rail system,
but even that should still be part of the live load because the space
could be changed so that there is no crane in that area and the rails
might be removed.  The only scenario that I could think of where a crane
MIGHT be considered dead load would be for a habor, off-loading shore
crane that operates with a boom (i.e. must swing the hoist around to be
over the ship and then swing back around to the shore side).

HTH,

Scott
Ypsilanti, MI


On Tue, 23 Jul 2002, Eric Green wrote:

> A client wants to install a rolling file deck in an area designed for 50
psf
live load. The file deck, which will be fixed to the floor, covers a 13x17
foot area and weighs 34 psf for the file system and 122 psf (max capacity)
for
the contents (files). How would you treat this under ASCE 7? Is it all live
load? Could the file cabinet be considered fixed equipment and called dead
load? Could it all be considered fixed equipment and hence be considered
dead
load?
>
> Using a crane as an analogy, the crane is dead load but the weight the
crane
lifts is live load. Is this a reasonable approach?
>
> Eric Green
> -speaking and asking for myself, not my employer
>

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