Building a water tank

[vpd66]

Hello, I've had this project in mind for a year or so and have been hoping for something surplus or scrap to turn up, but no such luck. What I need is to build a square tank 5' wide by 6' tall by 7' long. It should hold about 1500 gallons. It will just hold water and it will have a man hole on the top to fill it. It will not be pressurized and it will not be under any pressure and will be open to the atmosphere. How thick of steel should I build it out of? I'm thinking 1/4". Does anyone know how to calculate the weight of water on tank sides? I'm a welder by trade and have no problem cutting and welding the tank. I just need to do the engineering. Back 6-7 years ago when steel was affordable, I would have just built it out of 1/4" steel and if it bludged out the sides to much i would just weld reinforcements on the sides. Steel is just to costly these days for "Redneck engineering". LOL

 

[Artisan]

5x6=30x7=210Sq Feet of water.

1 cubic foot = 7.480 519 480 5 gallon [US, liquid] x 210 = 1570.9 Gallons.

Water weighs 8.34 pounds per gallon x 1570.9 = 13,101 Pounds of water
plus your steel... 13,101 pounds on 5x6= 30 square feet.

13,101 \ 30 = 436.7 pounds per square foot at the bottom for weigh straight
down. I would be more concerned about my bottom I thunk.

Swimming pools are made of really thin metal...it is the frame that does the work, yes?

1 foot of water exerts a pressure of I think .433 pounds per foot so you have 2.59 pounds of pressure at the very bottom if your full, subtract .433 for each foot you empty out of the tank.

Get an engineer to tell you about horizontal forces. :laughing:

I think I might concentrate on a good frame and maybe use 1/8" for the tank with maybe 2" x 2" x thinwall square tube frames bottom, 3 middles and a 3" or doubled 2" top.

Did you think about finding the local farm supply and just buying a cattle water trough? Or maybe just pick up one of these.

 

[mjncad]

I'd just buy a plastic tank and be done with it. No rust to worry about; but algae could be a problem if above ground and exposed to sunlight. However; there are black tanks out there to counter the algae issue.

http://www.watertanks.com/


Or are you just looking to build a tank because you can? If so, go for it.

 

[MarkV]

Considering the cost of steel a plastic septic tank might be more affordable and easier.

MarkV

 

[vpd66]

Plastic is out of the question. The tank is going to be used has a heat storage tank. The water will be heated to 180 degrees. The tank also is custom sized to fit into an already built shed, so the size has to be with in a foot of every dimension. Like I said, I've searched around for over a year and have not found anything prebuilt that would work. I'm sure has soon has I purchase the steel, something salvage will pop up.

 

[vpd66]

5x6=30x7=210Sq Feet of water.

1 cubic foot = 7.480 519 480 5 gallon [US, liquid] x 210 = 1570.9 Gallons.

Water weighs 8.34 pounds per gallon x 1570.9 = 13,101 Pounds of water
plus your steel... 13,101 pounds on 5x6= 30 square feet.

13,101 30 = 436.7 pounds per square foot at the bottom for weigh straight
down. I would be more concerned about my bottom I thunk.

Swimming pools are made of really thin metal...it is the frame that does the work, yes?

1 foot of water exerts a pressure of I think .433 pounds per foot so you have 2.59 pounds of pressure at the very bottom if your full, subtract .433 for each foot you empty out of the tank.

Get an engineer to tell you about horizontal forces. :laughing:

I think I might concentrate on a good frame and maybe use 1/8" for the tank with maybe 2" x 2" x thinwall square tube frames bottom, 3 middles and a 3" or doubled 2" top.

Did you think about finding the local farm supply and just buying a cattle water trough? Or maybe just pick up one of these.

Thanks for the info! I was thinking of building it like you would stud a wall with 2"-3" steel channel for the studs maybe 21" on center and using 1/8" steel skin on the inside of the studs. I've seen quite a few of these tanks built out of 3/4" plywood and 2x6 studs run horizontal around the tank. They used epdm rubber for a liner. I'm a welder and perfer to work in steel then no rubber liner would be needed.

 

[BRBurns]

Swimming pools are made of really thin metal...it is the frame that does the work, yes?

Swiming pools can be made thin because they are round (typicaly).

You will have 2.6psi pressure pushing on the sides at the bottom. The bottom to the sides will be relativly well supported since it will be welded to the bottom plate (I assume). So you will have an average PSI of 1.3 on the entire side. 6048 square inches on the 7 foot side. 7862 lbs pressing on the entire 7 foot side.

It's been too long since college for me to remember how to calculate the load in the center exactly, but I'm thinking that 1/4 steel will bow significantly. However some angle iron going around the top and in an X pattern on it's side would help greatly.

 

[BHD]

Red neck engineer here

fuel tanks are Round. water tanks are round grain tanks are round,

Hum I wonder why?

if you make it round one could make it out of 16 gage, 10 gage would be really over kill.

I have a water tank that is ROUND that is 20 foot tall and 9 feet across it is either 3/16" I believe,

my son make tanks and there rolling out 1/4" sheets into about 10 foot cylinders for the oil company's and welding up tanks,

go to some place that has the rollers and have them roll you out the shell and then weld the seam top and bottom on,

If there is no one with a roller have them break it into segments 10 gage I would think would be more than strong enough. for that size of tank, if round in nature.

IMO

 

[SandburRanch]

For a lot less money than stud wall construction, it could be built similar to the way farm wheat truck sides were kept from bowing out. They had a chain inside ( heavy dog chain size ) from one side to the other with a simple chain binder, attached in which ever link chosen, drawing the sides together . A series of these each direction could be attached to stubs welded about a foot O.C. each way or #2 rebar might possibly be used with some planning.

 

[BRBurns]

For a lot less money than stud wall construction, it could be built similar to the way farm wheat truck sides were kept from bowing out. They had a chain inside ( heavy dog chain size ) from one side to the other with a simple chain binder, attached in which ever link chosen, drawing the sides together . A series of these each direction could be attached to stubs welded about a foot O.C. each way or #2 rebar might possibly be used with some planning.

That's a good Idea. Probably the best bet if he really needs it to be square.