frost depth additonal depth?

[delagina]

I don't normally have projects in the north.
is there anything I should add to this frost depth?
say most cities in Arkansas, it's only 10" below of footing right?

 

[Archie264]

You may want to check with the local jurisdiction's building department as often they have their own minimum value.

Also, whatever the recommended value I doubt if anyone would object if you rounded it up to the nearest half foot. I.e., 10" becomes 12", etc.

 

[TehMightyEngineer]

Keep in mind that site soil conditions greatly influence these values. That said; most engineers I've seen have gone with the typical region values or local requirements and round up to the half-foot as Archie said to keep the foundations easier to build for the contractor.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[26sig]

I wouldn't use this map at all. The general concept is there (colder and deeper in the north) but the numbers are just wrong. Perhaps there's a Safety Factor missing.

I work in the Ohio and Pennsylvania areas, and as a reference, southern Ohio (Cincinnati area) is about 30", and Cleveland is 42". In Pennsylvania, Erie is 4' while the southern edge of the western part of the state is 3'. Many owners in this area are nervous about using anything other than 48".

What you could do is contact the local jurisdiction, or failing that the State, and find out what the officially mandated minimum is. Or talk to a local Geotech.

 

[TehMightyEngineer]

Huh, I agree it does look off. I initially looked at Maine which is mostly consistent with my experience and didn't check any further.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[msquared48]

I would not use this map either.

It shows 5" where I am, but the local jurisdictions call for 12 to 18" minimum, and it does not address local geographic anomalies such as 14,000 foot mountains and mountain ranges!

Call the local building department as previously mentioned.



Mike McCann, PE, SE (WA)

 

[KootK]

Also, stay cognizant of the difference between open field values and values for use with heated structures. It was 4' whenI worked in WI and the is same I southern Alberta for heated structures.

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.

 

[KootK]

There may be better data in ASCE's shallow frost protection guide.

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.

 

[TehMightyEngineer]

and the is same I southern Alberta for heated structures.

What?

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[msquared48]

"I" = "in"

Mike McCann, PE, SE (WA)

 

[delagina]

anyone got a better map? I cant find in asce or ibc. no luck calling Arkansas building department.

 

[TehMightyEngineer]

I've used the air freezing index from here:

https://www.ncdc.noaa.gov/climate-i...formation/frost-protected-shallow-foundations

Combined with equation 2 from here: ftp://ftp.ncdc.noaa.gov/pub/data/normals/1981-2010/supplemental/documentation/afi-manuscript.pdf



Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[oldestguy]

While this discussion is going, no one brought up the location of the ground water. Also soil type is important. Take a site nest to a lake, thee he lake level is likely near to the elevation of ground water nearby. Try to use the map or other rule of local thumb and then try to predict the depth of freezing nest to the lake. Ice thickness nearby is a much better indicator there. Then take a site with clean gravel, as at LaCross, WI and estimate the depth of freeing under a roadway that usually is plowed. Then ask yourself why do water mains freeze at 10 feet depth in last part of December? In each case the presence of water significantly affects things as water give off heat of fusion before the cold front goes deeper. If there is little moisture, the freezing depth is much greater.

 

[TehMightyEngineer]

Well, I did mention soil types above and the NOAA link I posted talks about regional effects.

Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

http://www.americanconcrete.com

 

[oldestguy]

Mighty Engineer: My comment was directed to the original poster.

 

[dik]

catch the link

http://www.pavementinteractive.org/article/calculation-of-frost-depth/

THe link was added to show the variables... pretty complex.

In Lindsay, Ontario the depth of frost penetration is typically 4'... in a parking lot (cleared of snow), ice was found at 7' below grade.

In Winnipeg, Manitoba the depth of frost penetration is typically 6'... in a parking lot, ice was found at 13' below grade.

Dik

 

[KootK]

Depends on stuff & confirm with AHJ. This appears to be the same data as above and was reproduced in several official-ish places. I believe these are average values as upposed to extreme values which may be the discrepacy.

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.

 

[KootK]

Average values from national snow and ice Center.

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.

 

[KootK]

Supposedly extreme values from geodetic survey folks.

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.

 

[KootK]

These guys are killing it with regard to style and presentation.

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.