10,000 gallon "moat" in a geodesic dome

[Dragonstar]

Im really excited to see this, great idea. Im a horticulturist if you have any questions about the plants. One piece of advice pineapples are bromeliads they wont do well in aquaponics.

The pineapples will be nearby, not in the growbeds. And also I appreciate your offer and will hit you up!

 

[Dragonstar]

To the people saying 3/8 is too thin, thank you, this is exactly the kind of thing I was hoping to learn. My logic was that an inward curve would distribute the pressure. It was inexpensive so no big loss. If you were doing something like this, what would you suggest? Glass? A series of smaller windows? Flat or curved? Thanks!

 

[ca1ore]

The fact that the acrylic is convex to the water pressure may in fact help ..... it’s beyond my hobby physics am afraid LOL.

 

[Dragonstar]

600 gallon acrylic tank is 10' x 3' x 3' and uses 1 inch acrylic with top bracing.
Please don't take this as "1 inch will work".

Ok, I won't. Top bracing is fine. Full-on welded cover with 3/4 in plate steel and beams embedded 6 feet in the ground is fine too. I have lots of leeway and freedom to do whatever works. What would you do to get a window in the side of an earth-bermed doughnut tank?

 

[Dragonstar]

The fact that the acrylic is convex to the water pressure may in fact help ..... it’s beyond my hobby physics am afraid LOL.

I'm with you there. But I've already gained a few solid ideas here. Like, why didn't I think of top bracing before now? That's why I'm posting this way in advance LOL

 

[Pistondog]

To the people saying 3/8 is too thin, thank you, this is exactly the kind of thing I was hoping to learn. My logic was that an inward curve would distribute the pressure. It was inexpensive so no big loss. If you were doing something like this, what would you suggest? Glass? A series of smaller windows? Flat or curved? Thanks!

Explore the curve for sure, would be stunning.
Get an acrylic fabricater to help.
Will be $$$$, don't know the budget.

 

[N.Sreefer]

If its set into the ground or earth bermed it would work like a solid pond liner and wouldn't need to be thick

 

[Dragonstar]

This is what I was picturing as the original post. I'm thinking of different ways now.

 

[Dragonstar]

Here's the last one I did, 15,000 gallons. I don't have pictures of the finished product but it gives you an idea. In the case of this project here, that entire central island would be gone down to the same level as the rest.

 

[DaneGer21]

My in-laws have a HUGE geodesic dome! My father in-law and his Dad built it, literally. His Dad was a master welder and machinist, he designed and built all his own hardware for the project.

 

[Dragonstar]

That sounds awesome! That's my dream. I'm no master welder so I've put this off for years, but this hub design just totally spoke to me:

So I went to my friend's metalcasting shop and we cut down and filed 80 schedule 40 steel hubs.

I've got the strapping and foundation materials also. I'm taking my time with the lumber. I was going to use Brazilian hardwood decking, but I'm learning that there's corruption and they clearcut the Amazon to get to it so I'm looking for another option, like white oak.

 

[Dragonstar]

It has been a couple years. The project was delayed because of two reasons. One, I bought a house and moved to a new location. Also, the pandemic made lumber prices go through the roof, which would have quintupled my costs.

Lumber prices seem to be getting a bit more reasonable. And I've settled into my new house. So I'm back to designing this thing again in its new location.

New place, new challenges.

I have most of the materials for the geodesic dome. I also have most of the materials for the earthbag retaining wall. But I can't use my original concept, which was to dig a shallow, round "basement" and put in a retaining wall concentric inside it.

For several reasons (nearby trees, water main) I cannot dig. Instead, I must build up.

So the new plan is to build a circular earthbag wall with no breaks in it. (except perhaps embedded pipes for tank draining into a nearby creek. But essentially an unbroken circular wall.)

This part is no problem. I'd basically be building a large, 16" thick-walled pipe three feet tall and 24 feet in diameter. Like an above ground pool. That should be as stable as stable can be, since earthbags are literally made to be dams to keep floodwaters at bay.

I can also do the same thing inside, making a second round earthbag wall nested inside, filling it with water, and voila! 3000 gallon fishtank.

This is certainly the simplest and most structurally sound option. But it doesn't have any way to watch the fish.

So I'm back to my original quandry. How do I embed viewing windows into the inner earthbag wall? Do I even need an inner earthbag wall anymore, or can I just build a large plywood tank? I'm talking really large. Cost would be a problem.

But an earthbag wall nested inside another would not be that expensive, if I can think of a way to make a very large waterproof doughnut with viewing panels in the side. Fish safe, of course. And using what I have learned in this thread, probably 1" thick cell cast acrylic with top bracing.

Sigh. This is seeming unrealistic but I have not yet given up. The good news is a smaller scale version of this wouldn't be terrible to mock up and I could test the windows fairly easily. So that's my current plan: Make a mini version and try out the idea.