Frost Line for Grade Beam with Piles
Frost Line for Grade Beam with Piles
(OP)
If piles are driven, with a concrete grade beam poured over the pile cap, does the bottom of the grade beam have to be poured below the frost line, or having the piles driven below the frost line complies with placing foundations below the frost line.






RE: Frost Line for Grade Beam with Piles
RE: Frost Line for Grade Beam with Piles
This would include a temporary void form and loose fill retainers on the sides of the beam to keep the void open beneath.
RE: Frost Line for Grade Beam with Piles
I have, however, seen a few drawings by other firms that did not have the bottom of the grade beam below frost. They required a chisel point (frost point) on the bottom of the grade beam. I don't know how well this works if at all. I do not recommend it.
Perhaps someone else can comment.
RE: Frost Line for Grade Beam with Piles
How about interior grade beams? I've heard opinions that the building heat (unheated structures exluded) will prevent heave, and therefore interior grade beams need not be below frost, but I have not seen this in any code.
RE: Frost Line for Grade Beam with Piles
If you are in a normal location, which I assume is the case, even without a frost protected design the interior portions will not freeze.
RE: Frost Line for Grade Beam with Piles
http://irc.nrc-cnrc.gc.ca/cbd/cbd026e.html
RE: Frost Line for Grade Beam with Piles
The bottoms of all the grade beams were angled such that one vertical side was deeper than the other and the bottom of each grade beam was then sloped at about a 45 degree angle as you looked at the cross section.
I guess the idea was to allow the heaving clay to slide past the beam...but then you wonder, what the heck is holding the building up? Aren't you also knifing down into the soil with your gravity loads?
Our project was a complete excavation UNDER the whole slab and an installation of drilled piers and supplemental steel beam framing to completely support the house. The knifing (chisel point) didn't work obviously.
RE: Frost Line for Grade Beam with Piles
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