Typical Drilled Pier Sizes

Here's a company document that shows several types of augers.
They list the range of diameters available but not the actual diameter increments.


In the past I've used diameters as follows:
24
30
36
42
48
54
60
66
72
and have used a 90" once as well.

I've seen 96" as well. I've seen 6-inch increments up to 72, then 12 inch increments above that. I have heard of up to 12-foot diameters.

Some jurisdictions require shafts in excess of 30" or 36" if they require hand inspection or they may require that the caissons have a metal sleeve, too.

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So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik