Cut and Pasted from 2002 Arema

SECTION 3.3 DEPTH OF BASE OF FOOTINGS
3.3.1 SELECTION OF TENTATIVE DEPTHS (1995)
On the basis of the data concerning the subsurface materials, tentative elevations for the bases of the footing should be selected. Unless special provisions are made, the depth shall not be less than the depth of frost
penetration, scour, or, in expansive clay subsoils, less than the thickness of the zone of significant volume
change of the subsoil due to seasonal moisture variations. Footings should be placed below disturbed shallow
soils, uncontrolled fills, collapse susceptible soils, and organic soils.

Sorry, couldn't copy and paste the frost penetration map. However, here is the text from above and below the mao.


Concrete Structures and Foundations
© 2002, American Railway Engineering and Maintenance-of-Way Association
8-3-6 AREMA Manual for Railway Engineering
3.2.4.3 Depth of Frost and Volume Change
a. The maximum depth of frost penetration shall be determined, usually on the basis of local experience
and records. Figure 8-3-2 is a map showing the depths of frost penetration in the contiguous 48 states.
Similarly, in regions of excessively swelling or shrinking soils, the depth to which significant volume
changes occur as a result of seasonal variations in moisture content shall be determined.
b. Permafrost, or permanently frozen ground, exists in the northern hemisphere in arctic and subarctic
regions. Although the southern boundary of permafrost is irregular, it may extend as far south as the
50th parallel. Foundations for structures, in areas of permafrost, should be designed in such a way as to
not disturb the permanently frozen ground; or if this is impossible, the influence of the foundation on
the permafrost should be predicted so the effect of the changes can be accommodated in the design. A
geotechnical engineer with experience in these ground conditions should be consulted for design of
foundations to be placed on permafrost.
Figure 8-3-2. Extreme Frost Penetration, in Inches, Based upon State Averages. Source:
U.S. National Weather Records Center

The map shows a 50 inch frost contour (extreme penetration) near northern Boston.

PEinc,
Thanks for the info.  You've been most helpful.

PEinc:
Is the reference on-line?  If so, you can include it in your (future) post in this fora...

Include something like the following in your post (change for the image you wish to include):

[img http://www.mysite.com/happy.gif]


You may have to do a little investigative work to determine where the mage is located on the other site -

Please see FAQ731-376  by VPL for tips on how to make the best use of Eng-Tips Fora.

The AREMA Manual is not available on-line. AREMA charges big bucks for the Manual. I think it costs over $300.00 for  AREMA members, over $400.00 for non-members.