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Re: IBC Special inspection for Slab-on-Grade supporting HVAC unit.

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Scott-

Don't your panties in a bunch.  You're being way too senstive. 

I was trying to emphasize (not necessarily to you) that a simple SOG
may not be so simple.  They're not always just something to keep the
dirt out of the building.

In my post I should have said "one's howework"  rather than "your
homework"; which could have implied the specific "you" (Scott) when I
really meant the general "you" (one).

My main point was that Elias had totally lost sight (if he ever had
sight)  of common sense reality & was way too focused on finding (in
the wrong spec) something to hang his hat on; the typical refuge of
the code monkeys who seem to predominate in the CE/SE world.

Come on, he was stressing & obsessing)over a pad for a 1 kip HVAC unit
even after Stan had tried to enlighen him!  Unless it was back life
support for the space shuttle it seemed pretty much like a no
brainer..

My secondary point was that a "simple SOG" can bite one in the ass if
one is not careful.


JMO / YMMV

cheers
Bob



On 5/27/05, Scott Maxwell <smaxwell(--nospam--at)engin.umich.edu> wrote:
> Bob,
> 
> I am curious...where in my post did I say that a non-structural slab such
> as SOG with wheel loads did not need to be properly designed (i.e. "doing
> your homework")?  That is funny, I don't recall ever just saying or
> implying that you just pick a slab design out of thin air with no design
> or thought.  Must be my imagination.
> 
> My point was that a SOG with wheel loads is still technically not a
> structural slab (which you seem to agree with).  It _STILL_ needs to be
> designed properly.  It is just that the slab its self is not design purely
> to take the load by structural action back to some other element.  The
> load is largely transfered to the ground directly through the slab by
> direct bearing not "spanning" or bending.  It still definitely requires
> design so it will not fail (i.e. deform, crack, settle locally, etc) under
> the applied load (i.e. wheel load).
> 
> Regards,
> 
> Scott
> Adrian, MI
> 
> 
> On Fri, 27 May 2005, Robert Kazanjy wrote:
> 
> > Elias-
> >
> > Are there no senior engineers with common sense to share at your firm?
> >
> > Stan gave you an ecellent answer.
> >
> > Scott, while a SOG that is subject to wheel loads (esp hard tire
> > forkf) may not strictly be a structural slab, not doing your homework
> > could cause everyone involved  a lot of headache.
> >
> > cheers
> > Bob
> >
> > On 5/27/05, Scott Maxwell <smaxwell(--nospam--at)engin.umich.edu> wrote:
> > > Elias,
> > >
> > > Stan basically answered your question...but to say it a again, SOGs are
> > > generally NOT structural.  Technically, it is the SOIL that is doing the
> > > "work" not the slab.  For a SOG, the slab will generally be designed to
> > > minimize cracking if the soil does consolidate in local spots, but the
> > > whole idea of a slab on grade is that it is the soil that is supporting
> > > the loads.  This is precisely why ACI 318 does not apply to SOGs...they
> > > are non-structural and ACI 318 is for STRUCTURAL concrete.
> > >
> > > I will kind of disagree with Stan some...if the SOG is designed for wheel
> > > loads, I believe it is still considered to be non-structural.  For such
> > > conditions, it is still generally the soil that takes the load with the
> > > slab being "stiffed" to help spread the load a little more.  If the SOG is
> > > designed to span some distance, then it might be considered structural.
> > >
> > > Thus, the "non-structural slabs supported directly on ground" exception
> > > that you cite applies to your case...at least based upon the information
> > > that you gave, that would appear to the be the case.
> > >
> > > Regards,
> > >
> > > Scott
> > > Adrian, MI
> > >
> > >
> > > On Fri, 27 May 2005, Elias Hahn wrote:
> > >
> > > > I tend to agree, but I can't find anything to cite.  There are only four
> > > > exceptions given in the IBC - Isolated spread footings (under 3 stories),
> > > > Continuos footings (some requirements), "non-structural slabs supported
> > > > directly on the ground." and some foundation walls.
> > > >
> > > >
> > > >
> > > > So, my follow-up question - what differentiates a structural slab and a
> > > > non-structural slab?
> > > >
> > > >
> > > >
> > > >   _____
> > > >
> > > > From: Arvel L. Williams, P.E. [mailto:awilliams(--nospam--at)gwsquared.com]
> > > > Sent: Friday, May 27, 2005 12:52 PM
> > > > To: seaint(--nospam--at)seaint.org
> > > > Subject: RE: IBC Special inspection for Slab-on-Grade supporting HVAC unit.
> > > >
> > > >
> > > >
> > > > Elias,
> > > >
> > > >
> > > >
> > > > Unless the existing building is in a use category that is considered life
> > > > essential.  Such as a hospital, water plant, etc.
> > > >
> > > > Even then, its a long shot on this type of foundation.  Special Inspection
> > > > is usually required only on deep foundations, deep fill, some type of
> > > > structural steel, pre and post tension concrete and a few other items that
> > > > are "special applications" and all building 3 stories and taller.
> > > >
> > > >
> > > >
> > > > So, for your little mat, I would say no.
> > > >
> > > >
> > > >
> > > > Arvel
> > > >
> > > > -----Original Message-----
> > > > From: Elias Hahn [mailto:ehahn(--nospam--at)eepdx.com]
> > > > Sent: Friday, May 27, 2005 1:22 PM
> > > > To: seaint(--nospam--at)seaint.org
> > > > Subject: IBC Special inspection for Slab-on-Grade supporting HVAC unit.
> > > >
> > > > I recently designed a SOG (~10'x15', 6" thick, thickened edge) for a HVAC
> > > > unit (~1000lbs) for an existing building.  Our standard general notes call
> > > > for special inspection for steel and concrete placement.  Is this
> > > > applicable?  There is very little good information on SOGs in either the IBC
> > > > or ACI 318.
> > > >
> > > >
> > > >
> > > > Thanks in Advance,
> > > >
> > > > Elias Hahn, EIT
> > > >
> > > > Evergreen Engineering, LLC
> > > >
> > > >
> > >
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