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Re: stack foundation

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Ken Peoples wrote:
 
<<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.>>
 
From your email I assume that someone else is doing the actual stack design. I presume that he has provided design forces at the base of the stack for your use as well as an anchor bolt layout.
 
There is a good section on circular/hexagonal footings in the footing chapter of the "Handbook of Concrete Engineering", Mark Fintel et al. I used their method to get soil pressures for the design of a stack foundation similar to yours 7 or 8 years ago. Worked well. My copy of the book is dated 1974. If you'd like a photo copy of the relevant sections please contact me offline.
 
I use a limit states code for design so the overturning moment (wind) is multiplied by 1.5 and the resisting moment (dead load) is multiplied by 0.85. The "factor of safety" would be 1.5/0.85 = 1.76.
 
I check the soil bearing pressure at specified (allowable) load levels and design the footing based on soil pressures at factored load levels.
 
Footing design is pretty standard but on a larger scale.
 
Can't answer your "heat" question off the top of my head. You may want to consider low heat of hydration cement but you'll need more knowledgeable advice than I can give.
 
Hope this helps.
 
John MacLean