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Re: Min. Reinforcement in Pedestals

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Dear Mr. Labbe

Thank you for your useful hint.

Best Regards,
A. Karimzadegan


----- Original Message -----
From: "Raul Labbé" <rlabbe(--nospam--at)ctcinternet.cl>
To: <seaint(--nospam--at)seaint.org>
Sent: Thursday, December 27, 2001 6:19 AM
Subject: RE: Min. Reinforcement in Pedestals


Besides all what I've seen exposed herein, I recall
that usually these pads are receiving anchor bolts
(A.B.),sometimes with loading cases involving important
upwards thrusts. If close to the perimeter  A.B. result in
the lack of enough one side-concrete to allow for the
development of the required anchoring concrete cone,
this should be covered with the proper rebar, both vertical
and horizontal ties. Usually, this steel requirements are
governing over all skin rebars.
-----Mensaje original-----
De: Roger Turk <73527.1356(--nospam--at)compuserve.com>
Para: seaint(--nospam--at)seaint.org <seaint(--nospam--at)seaint.org>
Fecha: Miércoles, 26 de Diciembre de 2001 05:36 p.m.
Asunto: RE: Min. Reinforcement in Pedestals


>Something 6m (~20 ft) in diameter and 1.3m (~4 ft) thick with only .3m (~1
>ft) protruding above ground looks more like a thick slab to me rather than
a
>column or a pedestal.  Therefore, I would reinforce it as a slab, not as a
>column or pedestal.  Without running any numbers, it would seem that
>temperature and shrinkage would be a concern as well as any stresses
produced
>by vibrating machinery.  Circumferential reinforcing would be prudent if
the
>machinery is producing any significant vibration.  It is difficult for me
to
>conceive compression as a controlling factor and with a thickness to
diameter
>ratio of 1.3:30, bending certainly shouldn't be a factor.
>
>HTH
>
>A. Roger Turk, P.E.(Structural)
>Tucson, Arizona
>
>Daryl Richardson wrote:
>
>. > Karimzadegan,
>
>. >         Unless you can find some code requirement to the contrary or
some
>. > loading that requires greater reinforcing I would be inclined to use #6
>. > (20 mm diameter) bars at 12" (300 mm) each way on all exposed surfaces.
>
>and Scott Haan wrote:
>
>. > ACI 318-99 Section 10.9.1 says the minimum compression member
>. > reinforcement is required to be between .01*Ag and .08*Ag. ACI 318-99
>. > Section 10.8.4 says you cannot reduce the minimum compression member
>. > reinforcement to .005*Ag in areas of high seismic risk.
>
>In response to A. Karimzadegan's post:
>
>> I have a question regarding the Min. reinforcement which we shall use
>> for the large pedestals. The question is the for the pedestals under a
>> large equipments (e.g. 6~7m in Dia. ) we need to construct a pedestal
>> to reach to the required elevation ( e.g. from -1.000m below ground to
>> 0.300 above ground with 6m dia. pedestal ). It seems that application
>> of about 1% or even 0.5% reinforcement is very large and unnecessary
>> and in these cases the pedestal action is more close to a foundation (
>> for which the main reinforcements shall be top and bot. bars instead
>> of vertical bars ) instead of column action. If anyone have any useful
>> suggestion in this regard, please let me know.
>>
>>
>>
>> Best Regards,
>> A. Karimzadegan
>> PIDEC Co.
>> Shiraz
>> Iran
>
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