Moving the horizontal beams further apart so that the support the edge of the IBC is definitely a good idea. And while adding the vertical pillar between the midpoints of the horizontal beams is a good idea, going diagonally from the midpoint of the top beam to the concrete blocks on the edges would be even better. That configuration is stiffer and more stable.

But you should also make the horozontal beams shorter. The pillars should ideally be next to the IBC. Structurally it doesn't make much sense to have the columns as high as they are.

A minimal structure would have corners of the IBC resting on top of the 4x4 columns, with horizontal beams forming two rectangles around the top and bottom of the columns. Add some diagonal braces and you'd be done.

Hi Roland,

Roland: Good points. From what I see your and my main point hasn't been heard yet?

The design looks cute but when the wood gets old or some of the joints get weak a catastrophic failure will likely occur with who knows what damage to the things nearby. Hopefully not people.

There is nothing like observing other failures to teach fail safe design. The tank will become, once it is filled with water, a VERY VERY heavy object. IMHO It needs strong support and also fail safe backup support.

Enough said ??  I hope so.

John

Gotta say, I think you guys are over thinking and building this one. These tanks are designed to be stackable and stable. Why not just stack one on the other? You get twice the amount of water, which you will find easily fills up with rain water (525-660 gallons is not that much water in the grand scheme of things). You can plumb the fronts of the tanks so they fill in unison but can be drained separately. I've been using them stacked for a while, even emptying the bottom one first and having them shift to what looks like a dangerous degree. Ive even climbed up one that was tilting and had the bottom tank empty, all while on a slope. It didnt even come close to falling. Is easy enough to empty them to reset and level once they settle. You'll probably get more height on the top one if its stacked as well.

Hi All,

Let's see 660 gallons at about 9 lbs. per gallon.

Right around 3 tons.

The weight of a car more or less.

Not a big deal for some I suppose?

I wouldn't want it to fall on my toe or Anna's or Mark's for that matter :).

John

Stacking IBCs would certainly be OK.

According to this brochure [PDF] you can stack up to four IBC's in a static situation. Even in a truck you're allowed to stack them two high when they're filled with water.

Note that this is valid for new IBC's with a steel base like the one shown on your pictures. When the steel is rusty or if there are broken welds or rivets the safe load will go down in a hurry.

Putting a steel IBC directly on wet soil is probably not a good idea in the long run.

W.r.t. overbuilding; Basically every structure is overbuilt. It's basic engineering practice to design structures for three times the nominal static load. Only in e.g. aircraft engineering where weight is of the essence and lots of effort is put into testing and discovering actual loads lower safety factors are used. And for e.g. off-shore equipment where conditions can be rough and replacement very expensive it is not unheard of to use a safety factor of 10.

Yes, i dont think its a good idea to build a structure for elevating a very heavy tank of water that could potentially fail. These tanks are structures and designed to be stacked. They would take some serious negligence to fall over while stacked. You will be able to easily adjust them if they do lean to a worrying degree.