Concrete Reinforced Floors

[alchemist99]

I know there are a lot of posts regarding concrete floors, but I have not seen an exact recommendation or formula for determining the exact strength requirements per gallon.

In other words, does anyone know (exactly) how many inches of reinforced concrete are needed for a 140 bbl tank? (Diameter is 8.5 feet).

Also, does anyone have a good recommendation for a concrete company in California who has reasonable prices for reinforcing about 1500 square feet.

Any idea of what this might cost.

From what I've read, I'm looking about 10-12 inches of reinforced concrete.

Thanks!

Definitely need to figure this out before we move in to our new facility so it only has to be completed once!

[dick murton]

That is probably because most of us are brewers, not structural engineers who understand detailed soil structure and strength, and loading on floors. If you think you need that depth of concrete, then you really need to speak to a structural engineer who can take into account all the factors required, such as underlying soil structure, tank weight and loads on individual support legs, overall fllor loading and any impact on surrounding walls etc. If you lie in an earthquate risk zone then I would expect the design to be very different from a stable rock based, or silt based ground structure

My recommendation is definitely - don't consider designing it yourself. You also need to consider the insurance implications of DIY build, let alone design

[tsewong73]

I hope this helps. This was posted about 5 years ago by Brian Sollenberger from Diamond Knot and I've kept this (and a few of his other formulas) ever since. Read the original question to gain insight into Brian's response. You should be able to make your own formula and fill in your own numbers from this.


Concrete Floors and Load

I just had a core sample taken in my proposed brewery site and it showed a 4", very lightly reenforcement, slab over packed earth. I was told by a engineer that this would not hold the weight of full 40 bbl tanks. 

Has anyone been faced with this problem, and how did you deal with it. I don't want to have to rip up the floor and lay down a new reenforced slab, and I don't want to add a 4" slab on top of the existing slab if possible. 

Does anyone have pricing on this type of excataing work?

I figured 1250 gallons of beer @ 8#/gallon spread over 4, 6" feet. Adding in 5000 pounds for the weight of the tank this would give me 7460# per square foot. Does this sound right?

thanks for any help and advice


Scott

Well........

Scott,

What makes it tough is the fact that your tanks will put a point load at each foot location.
The way I see it:


1250 Gal x 8 lb/Gal = 10,000 lb


10,000 lb + 5,000 lb = 15,000 lb


15,000 lb / 4 ft = 3,750 lb per Fermenter foot


6" DIA foot = 28 sq-in area = .1944 sq-ft


4 x .1944 sq-ft = .7776 sq-ft total


15,000 lb / .7776 sq-ft = 19,290 lb / sq-ft


However: 19,290 lb / sq-ft and 144sq-in / sq-ft = 134 lb / sq-in [psi]




Though non-structural concretes can be as low as 2,500 psi in compression, you still run a big risk of cracking due to bending loads if the substrate is not fully compressed. Literally, the slab bends under the weight and cracks. Concrete is awsome in compression but terrible in bending and tension.

A couple of options might be:

1.) Place large steel plates below the tanks to disperse the load over a greater surface area.

2.) Drill out piling cores at each foot location down to a couple of feet each. Make them about 1' x 1' square. The 2 ft depth may be overkill.

3.) Consult a concrete contractor / engineer and show him the data. They may deem the installation safe as is, but will really quiz you on the substrate.

Good luck!

Brian Sollenberger

Diamond Knot Brewing Co.

Mukilteo, WA


Cheers,

[nohandslance]

Call Todd @ Jergensen Construction, CA Lic. 536592. He has experience with brewery tennant inprovements and all the software and knowledge to get your brewery floor just right, not to mention one of the best finishing crews so your slab,floors are smooth as silk.

Lance
Rebel Malting Co.
Reno, Nevada USA
775.997.6411

[dick murton]

Don't forget to ensure there is a really good slope to the drains, not the other way round as seems to be de rigeur in most places I have worked.

[alchemist99]



1.) Place large steel plates below the tanks to disperse the load over a greater surface area.



2.) Drill out piling cores at each foot location down to a couple of feet each. Make them about 1' x 1' square. The 2 ft depth may be overkill

Very interesting suggestions.

Has anyone used either of the options above. Seems like either would definitely save money vs reinforcing the entire floor. Although stainless is pretty expensive.

Any ideas for HACCP ceiling compliance?? Most breweries I have toured have exposed beam ceilings but we are trying to have something water tight and cleanable.

I love probrewer!

[Alex T]

Hi,

We have done two different methods in the past for our 200HL tanks.

1) rip up the entire floor and lay a new slab. Very messy and expensive job....

2) we have a couple of tanks where we actually had a different structural engineer take a look and he recommended installing small square concrete plinths under each tank leg (there were six) on top of the existing pad with rebar tying the plinths back to the pad. Much easier, not to mention less expensive.

Item 2 of course depends on the strength of the original slab (we had 150mm thick slab already).

But I agree with Dick here - you shouldn't be doing these calcs yourself unless you are a structural engineer. Tanks do fall over.... especially given you are in a serious earthquake zone. Either find an engineer to have a look, or get your builder to sort it for you (as they will use engineers a bit, I would have thought). Should only be a small fee for the engineer (but hey, they are expensive, so expect something like $500 to $1000). Or you may be able to barter with beer......

Cheers,

Alex

[South County]

Concrete reinforced pilings for each respective leg. You would treat it just like a vertical in a building structure. As stated should be sized by and engineer.