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Re: information bulletin

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Richard:

A slight correction...ACI 360R-92 (Design of Slabs on Grade) is _NOT_ a
standard and cannot/should not be referenced in a code.  _ALL_ ACI
documents that contain an "R" in the number are _NOT_ written in mandatory
language.  This means that they CANNOT be used as code "level" documents
and that they should not even be used in Project Documents
(specifications, etc) by way of reference.  ACI is clear to point this out
with the following warning that is contained on the first page of such
documents including ACI 360R-92:

"ACI Committee Reports, Guides, Standard Practices,
and Commentaries are intended for guidance in de-signing,
planning, executing, or inspecting construction,
and in preparing specifications. Reference to these doc-uments
shall not be made in the Project Documents. If
items found in these documents are desired to be a part
of the Project Documents, they should be phrased in
mandatory language and incorporated into the Project
Documents."

If the intent is to get the content of ACI 360R-92 into code, then it
needs to be re-written in mandatory language by the committee or someone
else.  Just referencing ACI 360R-92 will not get you anywhere as
non-mandatory language documents _DON'T_ really require anything, but
rather recommend or "suggest" things.  Thus, it would be VERY difficult to
enforce it.

As to what the IBC and UBC do in terms of slab on grade, it is not
suprising.  Most people have the misconception that ACI 318 applies to
slabs on grade.  IT DOES NOT, with some minor exceptions (see section
1.1.6 of ACI 318).  And since the concrete portions of the IBC are
basically ACI 318, this means that unless something else is added into the
IBC or referenced from the IBC, it too will not really deal with slabs on
grade.  The only thing in the IBC that I am aware of that directly deals
with slabs on grade is section 1911, which are some very minimal
requirements.  In a similar vein, since the concrete provisions of the UBC
are basically reprinting of ACI 318 with some modifications, it would not
suprise me that is does not really deal with slabs on grade.  Again, there
would have to be something "extra" added beyond what is contained in ACI
318.

Thus, if L.A. is just planning on referencing ACI 360R-92, then their
lawyer will have plenty of work with little results because to my
knowledge such a minimal action will not be enforcable.  Instead you would
need to actual "convert" the recommendations of ACI 360R-92 (or some other
relevent recommendations...and there are some others that are not included
in ACI 360R-92...at least from what I recall) into some mandatory language
code provisions.  This is _SIGNIFICANTLY_ more work than just referencing
a document and will likely prove to be _SIGNIFICANTLY_ more controversial.

HTH,

Scott
Ypsilanti, MI


On Fri, 22 Aug 2003 rlhess(--nospam--at)hesseng.com wrote:

> SEAOSC recently had an interesting seminar at each of our three locations on
> Slab on Grade for Industrial Tilt-Up Buildings by Ajit S. Randhava, S.E.,
> which described some of the methods to design these ubiquitous structural
> (or are they non-structural) elements.
>
> This has brought up the interesting fact that the support of post and wheel
> loads on those building slabs is not specifically covered in either the UBC
> or the IBC.  This leaves room for much confusion among plan checkers and
> engineers as to the correct way to interpret the intent of the code when the
> slab is supposed to support such things as racks, mezzanines, equipment
> platforms, and heavy fork lift trucks.
>
> There is a standard that deals with this; it is ACI 360R-92, “Design of
> Slabs on Grade,” and this could be referenced in our building code with the
> necessary code language explanation and restrictions.
>
> The City of Los Angeles Department of Building and Safety has plans to
> develop an “Information Bulletin” on this for application within their
> jurisdiction.  This is an excellent first step in developing good code
> language that can bring about uniform and structurally correct handling of
> this important building element.
>
> Colin Kumabe, S.E., is in charge of this effort, and he would welcome help
> from interested engineers who would like to contribute some of their time to
> help develop this Information Bulletin.
>
> For those who are interested, please contact Colin at
> CKUMABE(--nospam--at)ladbs.lacity.org <mailto:CKUMABE(--nospam--at)ladbs.lacity.org>  or (213)
> 482-0447, or me at RLHess(--nospam--at)HessEng.com <mailto:RLHess(--nospam--at)HessEng.com> .
>
> Richard Hess
>
>
> (sent by)
> Virginia Walker
> Office Manager
> Hess Engineering Inc.
> Los Alamitos, California 90720
> (562) 799-9787
> office(--nospam--at)hesseng.com
>
>


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