water tank design

Larry Jaques fired this volley in news: snipped-for-privacy@4ax.com:

I find 62.43lb/cu.ft. in my water constants reference....??

LLoyd

Pure water - 62.4 lb./cu.ft. Sea water - 64.1 lb./cu.ft.

The water in this area is high mineral and dissolved solids and weighs in at 63.05lb./cu.ft. (actually weighed it for a pump ops class!)

It depends on your structural design. You have two requirements: one is a water-impervious "skin" that will contain water, the other is a structure that supports the weight of the water at desired height from ground. Both of these requirements can be accomplished by one entity, but they don't necessarily have to be. Example: a structure made of lumber and plywood with a thin water-impervious rubber skin.

16" deep water weighs 83.2 lb per square foot. That will be the pressure at the bottom of the tank, both on the bottom and on the sides.

If it is to be at some height above floor or ground, then the bottom structure needs to be a platform capable of supporting 83.2 lb per square foot. The sides will be in tension due to water pressure, but even very thin steel could handle this. A PET (plastic) soda bottle can handle over 100 PSI which is 14,400 lb/ft^2.

For structural ideas, look at some trailers. A 4' x 8' trailer rated for (and loaded with) 2662 lb would have 83.2 lb per square ft, and so on.

So, in other words, about a queen sized water bed?

Not exactly my area of expertise, but (when has that ever stopped anyone ;-)):

I've helped a couple of friends with a small winery. They have 1000 liter stainless steel fermentation tanks (about 40" diam x 60" high, IIRC). My impression of the tanks' construction is that they were nowhere near 0.10" thick. I can lift one (empty) pretty easily. When filled, they sit on some

4x4s, about 2' apart. So at 16" deep, I don't think you'll need anything too thick as long as you support the tank bottom.

These tanks have all welded and ground seams (food grade requirements not to have any place for crud to hide). I don't know how they were welded at the factory, but it must be possible to keep things from warping somehow.

The total weight of water bears on the bottom of the tank; you need to support that bottom, probably every foot or so, to keep it from warping. Any thickness that has been suggested is 'enough' with suitable support. If you set it on level ground, it can be a kid's vinyl playpool.

Your more significant problem is the 10' long straight sidewall, which will be bowed outward by water pressure; at 16", that pressure is rho * g * h =3D 62*(12**-3) *16 =3D 0.54 pounds/square inch The bottom of the sidewall, of course, is welded to a stressed sheet, and that will take about half of the force, the other half is

10 ft * 12 in/ft * 16 in * 0.25 * 0.54 psi =3D 259 lbs

None of the suggested sheet thicknesses will hold 259 lbs distributed load without deflecting on a 10' length. You need to put a rigid brace (something like a 2x6 or so) at maybe 8" from the bottom, to keep the sides straight.

Indeed. Id suggest one at the top as well.

Gunner

"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

At what temperature is that? When we get down to the .0x lbs. we better specify the temp and the value of G. :-) ...lew...

Lew Hartswick fired this volley in news:6amdndO26IO_fozXnZ2dnUVZ snipped-for-privacy@earthlink.com:

I'll look it up again, but I seem to remember that was at 20C.

In any case, a difference of two pounds per cubic foot isn't accounted for by a few degrees C.

LLoyd

On Mon, 18 May 2009 16:37:26 -0600, the infamous Lew Hartswick scrawled the following:

Egad, we missed the RH and sea level coefficients, too! Egg all over our faces, wot?

-- No matter how cynical you are, it is impossible to keep up. --Lily Tomlin

Then we have to adjust for the temperature rise from all the hot steel falling in.

jsw

Had heavy water numbers maybe ?

Mart> Larry Jaques fired this volley in

Put a 1/4" bead down the line - with a bead bender. It will strengthen the side very well.

Mart> >

Indeed it will. However if the bead gets flattened out...

Gunner

"Lenin called them "useful idiots," those people living in liberal democracies who by giving moral and material support to a totalitarian ideology in effect were braiding the rope that would hang them. Why people who enjoyed freedom and prosperity worked passionately to destroy both is a fascinating question, one still with us today. Now the useful idiots can be found in the chorus of appeasement, reflexive anti-Americanism, and sentimental idealism trying to inhibit the necessary responses to another freedom-hating ideology, radical Islam"

Bruce C. Thornton, a professor of Classics at American University of Cal State Fresno

Ummm, yeah, seems about that much, if you say so.

Say, if I put a one of them queen size water beds in the other corner of the house (catty whampus from the part which is sagging, you recon I might be able to raise the sagging end enough to rebuild the supports under there?

tschus pyotr

- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!

Upstairs? In a frame house?

No, I think it would lower the whole thing!

:)

Richard

Larry, That is what I said " The value of G" It not only is dependent on "sea level" but those nasty things called "mascons". and I did say hunderedths of a pound not the bigger difference. :-) ...lew...

Larry, That is what I said " The value of G" It not only is dependent on "sea level" but those nasty things called "mascons". and I did say hunderedths of a pound not the bigger difference. :-) ...lew...

Oh, good. I don't have an upstairs.

tschus pyotr

- pyotr filipivich We will drink no whiskey before its nine. It's eight fifty eight. Close enough!