Concrete weight limits


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Old 02-01-09, 12:58 PM
K
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Concrete weight limits

Please forgive me in advance if this is a silly question or the answer should be self-evident! I have a wood pellet furnace and probably go through 6 tons of pellets in an average New Hampshire winter (the furnace is pretty new so I can't give a better estimate). I don't have a basement so both the furnace and the pellets are in my garage (the furnace will soon be enclosed in its own little room as I think is required -- in any case right now there's nothing flammable within several yards of it, and I don't park my car in there). Anyway right now the pallets of pellets are just stuck in my garage any which way but once I use the current pellets and then get organized this summer (major project), I hope to carve out a permanent space at the back of the garage to store the pallets. The pallets are 48" x 40" x ~54" high and hold one ton each (which is 10 layers of 5 40-lb. bags each). I would like to add about 5 "layers" to each pallet (since I have enough height to do so), which means each 48" x 40" space will hold about 3,000 lbs. Most winters I would need 4 of these 48" x 40" spaces to hold the 6 tons, but next winter I will likely be storing twice as much (long story that I won't go into) so will have 8 of these 48"x40" spaces all lined up in a corner (probably 2 rows of 3 and 1 row of 2).

OK, I did a google search and saw several estimates for how much concrete slabs can hold and it seems like I should have no problem at all. (EG the LEAST I saw in various web sites was 1,500 lbs. per square foot [some said 2,000 lbs. per square INCH]; since a 48" x 40" pallet is about 4'x3.3' or about 13 square feet, it seems like it should hold 13 x 1,500 lbs. = 19,500 lbs., which is more than 6 times the 3,000 lbs. I am estimating?)

My question is, are these estimates accurate, in which case I should have no problem? The garage (like the house) is about 25 years old. I have no idea how thick the concrete is but I assume it is 4-5" thick (that's the usual?). The concrete seems to be in good shape -- no cracking that I've noticed.

I'd appreciate any help to ease my mind! Thanks!

-Karen in New Hampshire
 
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Old 02-01-09, 02:37 PM
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Concrete weight limits

That is not an excessive weight since it is reasonably well distributed. - Compare that to a 4000# car that is sitting at 4 spots with a 6"x6" "footprint".

Usually any reasonable soil will support support 2500 psf or you should not build on it.

Since you have no idea of the strength or thickness of the concrete or the type of soil, it is impossible to give you a definite yes or no.
 
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Old 02-01-09, 03:00 PM
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I'm assuming the house was built to code about 25 years ago so hopefully the soil was fine. So far I have had no problems at all with the several tons of pellets I have in my garage now. I guess I just wanted reassurance.

Even if the limit is 500 lbs. per square foot, which is WAY lower than anything I have seen, that would still be 6,500 lbs. per 13-square-foot area which is more than twice what I would be using.

Actually, figuring backwards, as long as the garage's concrete slab can support just 250 lbs. per square foot, I should be OK. When I think about it that way it seems like I should be fine ...

Thanks for the reply!

-Karen
 
 

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