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Slab-on-Grade Design

Slab-on-Grade Design

Slab-on-Grade Design

(OP)
Hello,

I can't seem to find any PCA design charts for slab thickness when all I have is a distributed load and no aisle. I need to design a slab for 2,000 psf tank resting on it. Where should I start?

RE: Slab-on-Grade Design

Try to find and consult 'Designing Floor Slabs on Grade by Ringo and Anderson'

A good structural engineer is often a blessing for others.

RE: Slab-on-Grade Design

I have never designed a slab to support a tank before, but if the tank is loading the slab uniformly, wouldn't the slab just be transferring the load directly to the sub-base through bearing? In this case I would think the slab is basically a high-quality sub-base for the tank - I have seen tanks supported entirely on gravel bases before. When you have aisles and point loads, the slab is required to spread the load and must be designed accordingly.

I 2nd PSEPK on his reference. Its a great book.

RE: Slab-on-Grade Design

(OP)
Canpro,

That is what I was thinking but I wasn't sure if there was more to it than that.

P.S.
I have access to the book from the engineer at my office and I looked online to buy one of my own. Why does it cost $800 to buy one? It doesn't specifically address pure uniform loads.

RE: Slab-on-Grade Design

Theres probably more to it at the edges of the tank where you would have some concentrated load, I wish I could offer more advice on this, but like I said, haven't done this before. Should be plenty of info out there on slab design for storage tanks though.

$800 seems steep for a book, but that is what Amazon is showing. I'd keep looking, must be a better deal out there. Feeling pretty lucky I got my copy for $2 at a book sale.

RE: Slab-on-Grade Design

The soil below the slab will try to resist the weight of the tank over an area that is larger than the tank, so there will be some bending in the slab. For your situation (2,000 psf, which is a heavy tank), I would isolate the slab below the tank from the surrounding slab. I would make the slab under the tank at least 8" thick. If the isolated slab is not larger than the tank, it will see no bending. If it is larger, design it like a spread footing or a mat footing.

DaveAtkins

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