Concrete Footings, ACI 318-08 Table 4.3.1

[kennyb04]

I have looked on a couple of the other posts regarding Tables 4.3.1 and Table 4.2.1 but am still not coming to the conclusion I need.

I am ultimately trying to decide if spread footings can be classified as Class F0 or if it has to be classified as Class F1. Typically our bottom of footing is below frost line but the top is not so I would think it would have to be F1. Even if the top of footing is below frost line, and there is a pilaster above, then the pilaster would be above the frost line.

It seems like there is an industry standard to use 3000 psi concrete for footings but according to these tables 4500 psi would be the minimum in most places.

Is there any way to justify using F0 for footings/pilasters. If the footing is classified as F1 then that also means the concrete will be air entrained (about 4.5% for 1.5" max. aggregate based on table 4.4.1). Going along with the same idea, then trench footings would also be F1, 4500 psi concrete, and air entrained. Does it seem excessive to have 4500 psi air entrained footings and trench footings?

 

[DST148]

So long as the footings and walls / pilasters are not subject to cycles of freezing and thawing, then both the footings and the walls / pilasters could be classified as class FO.
You could use 2500 psi for footings.