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

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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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