On the other hand, dry, clean, sand or gravel may freeze without heaving Heave can vary a lot from year to year depending on moisture conditions and weather. Frost depth always has been and should be to the bottom of the footing You are trying to avoid a condition where frost occurs in the soil directly under a footing and in which case the soil expands (or rather the moisture freezes and expands within the soil matrix) and dislocates the footing. For a floating slab on grade, what is best practice at an exterior door I assume the slab edge should get extended to the outside face of the wall
Does the slab edge need to be thickened If so, how much, or should it be turned down onto the strip footing/grade beam It seems to me that if. However there is still some potential for frost heave, especially of there are variations in the soil As mentioned in the other thread, would be best to insulate footings having inadequate cover (side of wall below grade and laterally over footing) to maintain soils thawed under footing. If frost depth is determined for a county, how many tests do they perform before the county is satisfied with their estimate of frost depth
It seems to me that there are a ton of variables that could affect frost depth, so am just curious how these numbers are typically determined. Hello, i am currently designing concrete drilled piers, and per the geotech report, the recommendations incur a 1600 psf design stress for potential frost heave The recommendations also state that placing friction reducing material can be considered as an alternate option to prevent damage. 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. A contractor is suggesting the use of 1ft deep, very wide concrete slab to support heavy rotating equipment The local jurisdiction has a required frost depth 42in
Can a very heavy foundation (while still below the allowable bearing capacity of the soil) eliminate the need to go below the 42. What are some of the best ways to have a slab on grade and yet protect against frost heave?
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