"underwater eco habitat" questions re: structure

[ebesan]

I was shown this project the other day.

http://www.seabase1.org/

I am not an engineer, but an architect; and reacted by scratching my head and wondering about several design and engineering issues (form and function)
1. a square shape?
Wouldn't the pressures be structurally uneven and extremely inefficient?
2. the 24 hr. tidal flow; tidal hydraulics; wouldn't the shape cause some potentially dangerous pressures? (inertia, drag, pressure differential, vortexes? what is the term for this, hydro-dynamics?)
3. shifting sand; 5 minutes just standing in an ocean and sand has covered my feet; wouldn't there be severe shifting and build-up? (I think of shifting dunes)
4. would it be realistic to sink this to the actual ocean bed? how stable is that, or can an engineering study determine? but regardless, would it make more sense to elevate the habitat on adjustable legs, allowing the water free movement below? (and easier construction/removal)
(see these Projects from the South Pole-

http://www.hbarchitects.co.uk/projects.php?project-list=extreme&id=0

5. and even consider a hydro-kinetic feature; propellers, or some technology to harness the constant tidal movement?

But lastly, without getting into a discussion on aesthetics, I personally would be looking at the Space Station, curved shapes with equalized pressure; marine life; submarines; a shape that would allow the tidal movement to pass; bio-mimetics.
This is a statement from the Project"s Sponsors-
"The base itself will comprise three floors constructed in the shape of a Mayan pyramid in homage to the civilization that once flourished in Belize."

Any ideas, advice, suggestions would be very welcome; this actually fascinates me as a very challenging design/engineering problem.
Thanks. Ebesan

 

[MikeHalloran]

Flat faces are certainly possible to build, but they don't remain very flat when a differential pressure is applied, and in general must be very thick to keep the deflection within reason.

Cylinders, OTOH, remain more or less cylindrical, and just shrink or stretch a bit depending on the direction of the differential.

The website authors may be visionaries, but they're clearly not engineers.

The idea of an underwater habitat is not new, either. See, e.g.,

http://aquarius.uncw.edu/

Mike Halloran
Pembroke Pines, FL, USA

 

[IRstuff]

There are plenty of examples of flat surfaced interfaces, e.g., Sea World aquariums, but they are extremely thick. The plexiglass panes seem to be on the order of nearly a foot thickness there.

The pressure on the lowest level with windows looks to be around 36 psi, which isn't that much more that what some large aquariums such as the Artic adventure aquarium at Sea World are designed for.

TTFN

FAQ731-376

 

[cloa]

There just isn't enough detail to even discuss the idea. The drawings are pictures not engineering diagrams- the most detail is that its designed for 60ft depth.

 

[Ussuri]

1. a square shape?
Wouldn't the pressures be structurally uneven and extremely inefficient?

The structure would need to be designed to withstand the pressure at the depth it is to be placed. Flat sided objects will attract more hydrodynamic loading than curved surfaces. There are plenty of flat sided structures on the seabed, although none this size I suspect.

2. the 24 hr. tidal flow; tidal hydraulics; wouldn't the shape cause some potentially dangerous pressures? (inertia, drag, pressure differential, vortexes? what is the term for this, hydro-dynamics?)

The wave, tidal, current, surge etc will impart loading on the structure. The structure needs to be designed to withstand these loadings.

3. shifting sand; 5 minutes just standing in an ocean and sand has covered my feet; wouldn't there be severe shifting and build-up? (I think of shifting dunes)

Possibly, or the opposite may occur and the structure is scoured out.


4. would it be realistic to sink this to the actual ocean bed? how stable is that, or can an engineering study determine? but regardless, would it make more sense to elevate the habitat on adjustable legs, allowing the water free movement below?

Possible, yes, realistic, dunno. The structure will need to be provided with suitable foundations in order to keep it stable. These could be piled or gravity based. You could have it on legs, but it would still need a foundation.

5. and even consider a hydro-kinetic feature; propellers, or some technology to harness the constant tidal movement?

Why not, this is just a concept so keep it in. In reality they are still a long way off making tidal power generation a viable technology but small scale tests are being conducted by a number of companies