frost heave
frost heave
(OP)
I am designing a house in Charlotte, nc where the contractor wants to run a section of the wall footing above ground so that a tree can be saved. The distance above ground will be 26 feet so he doesn't want the beam to span like a grade beam but to simply bear on top of the ground. Obviously if the footing is made heavy enough and reinforcement is put in the top it could resist any frost heave, but what force do I design it for. Has anyone ever done something like this before.





RE: frost heave
RE: frost heave
Regards
RE: frost heave
Even if your beam bears on the ground, you will have to compact the subgrade, probably for a depth of 6 inches or more, and may still damage the roots.
RE: frost heave
RE: frost heave
The weight of the structure will not compress the frost. In order to resist the heave, the structure would have to be heavy enough to push the frost heave down and compact or compress the soil underneath. If the structure is heavy enough to do this then it is too heavy to bear on the soil.
I know they don't like the idea but your only real choice is to use a grade beam as a lintel to span over the roots. Quite simply, using the ground surface as the support will eventually crack the structure.
Imagineer
RE: frost heave
As mentioned above, most structures are not capable of resisting frost heave, or at least without extensive insulation.
RE: frost heave
RE: frost heave
RE: frost heave
An option that disturbs a minimal amount of soil and should be readily available is "pin-piles". Basically small pipe piles that are great for carrying the relatively light loads of a residential structure.
Probably the easiest solution is to move the house if the tree must stay.
RE: frost heave
RE: frost heave