Frost Protected Shallow Foundations ASCE 31
Frost Protected Shallow Foundations ASCE 31
(OP)
No experience with doing a frost protected shallow foundation and I'm wondering if I'm missing something here, first glance appears too good to be true.
In my region (nyc) the code requires 48in. for frost protection:
1805.3.1 Frost protection. Except where otherwise protected from frost, shallow foundations, pile caps, and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:
1.Extending a minimum of 4 feet (1219 mm) below the lowest adjacent permanent exposed grade;
2.Constructing in accordance with ASCE-32; or
3.Erecting on solid rock.
ASCE-32 seems pretty straightforward, based on my air freezing index (afi) they allow a footing depth of only 12" with exterior vertical insulation and no horizontal extension.
Going from 48" to 12" simply by adding vertical insulation of R=4.5 doesn't seem right to me. The architect is really into it and it solves some other issues with excavation but I'm skeptical. Am I missing something here?
In my region (nyc) the code requires 48in. for frost protection:
1805.3.1 Frost protection. Except where otherwise protected from frost, shallow foundations, pile caps, and other permanent supports of buildings and structures shall be protected from frost by one or more of the following methods:
1.Extending a minimum of 4 feet (1219 mm) below the lowest adjacent permanent exposed grade;
2.Constructing in accordance with ASCE-32; or
3.Erecting on solid rock.
ASCE-32 seems pretty straightforward, based on my air freezing index (afi) they allow a footing depth of only 12" with exterior vertical insulation and no horizontal extension.
Going from 48" to 12" simply by adding vertical insulation of R=4.5 doesn't seem right to me. The architect is really into it and it solves some other issues with excavation but I'm skeptical. Am I missing something here?






RE: Frost Protected Shallow Foundations ASCE 31
this one is goofy.
RE: Frost Protected Shallow Foundations ASCE 31
RE: Frost Protected Shallow Foundations ASCE 31
I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.
RE: Frost Protected Shallow Foundations ASCE 31
RE: Frost Protected Shallow Foundations ASCE 31
This is a typical grade beam detail for us:
Based on IBC, my supervisor, an architect, determines the required insulation.
Both my supervisor and i hate grade beam foundations for PEMB due to the inevitable eccentric footings and the complicated rebar design within the footing to resist uplift.
We understand our contractor-clients' perspective in that it certainly is less expensive, therefore, we deal with that accordingly.
What we dislike even more is when the client wants a grade beam addition to an existing frost-wall structure.
Fortunately, i don't have to deal with that liability.
RE: Frost Protected Shallow Foundations ASCE 31
The 12" foundation depth for a FPSF in NYC is for only a heated building, defined as one which has a minimum monthly average inside temperature of 63 F or greater.