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Posted by RicodJour on November 2, 2006, 10:16 am
Mark wrote:
> Good morning.
>
> I am nearly ready to replace my 4x4 basement support post.
> As part of this project, I plan to cut a hole in the slab and
> pour a proper post footing using an 8" sonotube, A Simpson
> CB64 bracket, and a bag of 5000psi Sakrete.
>
> I will try to keep the hole small so that the sonotube is a
> fairly snug fit. . .may an inch or even less clearance all around.
> My question is, how would I properly fill the gap between the
> concrete pour and the side of the hole? I have a couple of ideas:
>
> - Pour concrete around the outside of the sonotube during the
> initial pour. The paper would be left in place in the "underground"
> portion, and removed where the footing projects through the slab.
>
> - Remove all of the sonotube after the concrete sets up. Backfill
> around the footing using (what?)
>
> Other suggestions?
Yes. Investigate the loads before you settle on an 8" sonotube.
Normally there is a spread footing under the sonotube to increase the
bearing area.
That 8" sonotube only has about .35 SF of bearing area. Guessing at a
soil bearing capacity of 2000 LBS/SF that sonotube will only be able to
bear about 700 pounds of load.
I think you are way undersized. Don't design a solution until you know
the loads involved.
R
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