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RE: stack foundation

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Ken,

Stacks and stack foundations are specialized designs.  Dynamic amplification
due to wind vortex shedding is what drives most stack designs especially in
multiple stack applications.  

The standard for steel is "Steel Stacks", ASME STS-1-1992.  Stack anchor
bolts must be tensioned.  Hydraulic tensioners are commonly used.  The
factors of safety are contained in the STS-1.

If it is concrete the standard is "Standard Practice for the Design and
Construction of Reinforced Concrete Chimneys (ACI 307-98)"; and Commentary,
(ACI 307R-98).

It gets really dicey if the stack is a steel guyed stack (common for flare
stacks).  You have to develop your own guides for thermal stresses, guy
initial tension, and ice loading.

Regards,
Harold Sprague


> -----Original Message-----
> From:	Ken Peoples [SMTP:lvtakp(--nospam--at)yahoo.com]
> Sent:	Tuesday, September 19, 2000 3:58 PM
> To:	seaint(--nospam--at)seaint.org
> Subject:	stack foundation
> 
> We have been asked to design a foundation for a 200-foot high, 20-foot
> diameter stack. Can anyone give me any "watch out for's" or direct me
> towards any reference information.  I am going to have a soils
> investigation by a geotech to be sure that we don't have any settlement
> problems using a "shallow" foundation.  I am guessing (this is in the very
> preliminary stages)  that the foundation will be something like a 25 foot
> hexagon maybe 8 feet thick.  What kind of factor of safety should be used
> for overturning for a structure like this? One thing that I was thinking
> might be a problem is heat because of the fairly large mass of concrete
> that will be needed.  All of your thoughts are appreciated.
> 
> Ken Peoples, P. E.
> 
> lvta(--nospam--at)fast.net <mailto:lvta(--nospam--at)fast.net>
> 
>  
> 
> 
> 
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