Reinforcing of pedestals for process equipment

[Mainu]

I have some doubts about the reinforcement of pedestals for the use of the industry equipment. A sketch is attached with concrete doubts,as example, about a chimney pedestal. If anyone know some good reference (book, code, ...) about this topic, I would be very grateful. Also about any comment in relation with the influence of dynamic effects. Thanks in advance.

 

[JoshPlumSE]

Excellent questions. I don't know of any code provisions that truly cover these types of pedestals. My thoughts:
1) I have an old "design guide" from the company I worked for in the mid-90s that frequently designed octagonal pedestals like this for vertical vessels. The notes in there regarding "dowels" are the following:
a) The pedestal must be tied to the footing with sufficient dowels around the pedestal perimeter to prevent separation of the pedestal and footing.
b) Dowels are customarily sized by computing hte maximum tension existing at the pedestal perimeter due to overturning moments.
c) minimum pedestal reinforcement for a 7' pedestal = 16 #4 ties @ 15 inches maximum

My impression is that this minimum reinforcement was there to help control surface cracking but that it would not be sufficient to meet the 0.5% min reinforcement requirement per ACI. I would assume something similar for the mat of top steel.

2) I remember having a conversation with one of our in-company code gurus at the time about the 0.5% requirement. His response was never wholly satisfying to me. Essentially that the code didn't have provisions for these types of foundation pedestals and that it was unreasonable to use the 0.5% min. But, that we didn't want to treat them as "plain concrete" sections either.