"Packed Stone" Foundation 1

[SrVaro]

Please see the attached sketch. I am working on a pro-bono project for a local camp grounds for the disabled. They are wanting to replace an existing firewood shed that is in disrepair with a new one. The column spacing is 6'-0" x 7'-9", with the largest column length of ~8'. It is to be used for storage of fire wood to keep it dry only, thus an unoccupied structure. They have received limited funding for materials and the construction is being completed by donated labor (a client of mine, thus how I got involved). To limit construction time, they have requested a "packed stone" foundation; burying the post within stone instead of concrete. I have seen similar for decks on the program 'This Old House'; where they use a lime mix and added water to harden. My issue is I do not know how to design this type of foundation. I have completed an internet search with no success. Either mircro piles, sub-base, or wall foundations are returned. I also did search of the forum.

My first issue could be I am calling the foundation type by the wrong name, but I did take a couple threads of my interest search on names and descriptions that seemed promising. But still no luck.

Does anyone have any information that could assist me in this type of design? I am thinking similar to any other embedded post, needing the lateral resistance associated with the diameter of the pier. But is there anything special with the stone to timber post interface that would limit the lateral capacity? Thanks in advance.

 

[jayrod12]

ASAE/ANSI EP486 is what you're looking for.

 

[jayrod12]

further to that. No realistically the stone will act as good or better than the native soil at the interface with your post. Provided it is adequately packed down.

One more thing, it is likely that uplift will govern, might want to think about adding a wood or concrete collar at the base to help with that. They can do it with a couple of bags of the redi-mix you buy from home depot.

 

[Canuck67]

In my area they are referred to as "rammed aggregate piers". A lot of telephone/hydro poles are installed as your sketch depicts with compacted limestone screenings filling in the void between pole and the existing subgrade.

 

[SrVaro]

jayrod12- Thanks. I was able to find what looks like several good resources by searching ASAE/ANSI EP486.

Cabuck67- Unfortunately "rammed aggregate piers" returns results for soil improvement not foundations.