Floating Concrete Shell and Honeycomb Structures
March 3, 2014 at 6:58 am #23025
Floating Conrete Shell and Honeycomb Structures emerge as “Technology of Choice” for Seasteading. They combine the durability needed for oceanic real estate, with the toughness required for handling climatic tail events, like Draupner waves and Hurricanes. This thread is dedicated to explore the “how to implement” of this technology for ocean colonization and floating business ventures. On large scale and on small scale. As the world becomes more and more ocean oriented it is predicted that the twenty first century will see more construction activity on the water then on dry land.
See more pictures on what is out there already on shell building and thin shell domes at:
See more pictures on oceanic concrete shell building:
http://www.pinterest.com/wellmer/oceanic-concrete-shell-building/March 25, 2014 at 12:50 pm #23230
I have asked several times about how to attach small cement bouyant structures (i call them “floaties”) to another structure. The floatie someone can bring to the water in their pickup truck, or lawnmower trailer, has a much higher chance of being used than a single piece 30ft anything. But even regardless of the vessel’s LOA, it’s going to flex in the water, and cement and concrete are known for being the least flexable material for building with, and having poor tensile strength. So if i wanted to replace a set of cylindrical steel pontoons with cement ones, to prove the cement is a better choice in that application, what is the best way to accomplish the replacement, such that the boat deck flexing (or not flexing) won’t stress the cement pontoons and crack them?
The only way i can see to do this with one long hull is many self-leveling hydraulics like house movers use, to keep an apparent non-flexing interface spread out over the pontoon, but with a much larger range of motion. That will become an maintenance issue very soon.
So has anyone actually done this?March 25, 2014 at 1:45 pm #23233
Concrete beam flexing under load.
You need to open to the idea that concrete in the widest sense is a composite material containing 3 elements binder (cement) fibers (rebar) and fillers (aggregates) – the property of the material is in the COMBINATION of components – not in the one of the components. The idea that concrete has a similar material property as a cement block is so fundamental wrong like the believe that a “carbon fiber composite part” has a similar behavior to coal. Whenever you combine the 3 elements right you will get a piece that has excellent flexibility great tensile strenght – so all the “problems” you try to solve with a incredible complicated “attachment sistem” are basicly “imaginary problems that arise from a wrong perception of the material”. If you build a hollow concrete beam – and do it right- you do not need to treat it like an egg – in general when you put concrete and steel together you use welding of rebar sticking out of the piece, cast jointing, bolting, epoxi bonding, grouting, as attachment technology.March 25, 2014 at 2:39 pm #23234
Ok, i do not see anywhere online how to mix cement to get that amount of bending.March 25, 2014 at 7:15 pm #23235
I did find where that photo was likely taken: http://phys.org/news3985.html or http://www.flexibleconcrete.co.nz/?page_id=127
People familiar with it say it’s all about allowing microcracking, and hoping the polymer fibers pull the cracks closed again. The cement does not stretch at all, so the outer radius of a bend is full of microscopic cracks between the fibers and the cement. The greater the thickness of the material bent, the greater the damage to the outer radius. Typical uses are under 2in/6cm thick and placed on top of regular cement to keep it from flexing(!!), this is useless for trying to take advantage of the bendyness for a taller or thicker casting. I remember laughing about this stuff years before U-M (re)invented it, and now i know why there’s no mention of how to make it online. There’s no structural use for it, and latex mixes of cement last longer as coating material. It’s maybe possible to pour it around steel rebar, so the cement seems to stretch as much as steel does, but since it’s microcracking it’s only going to let the ocean salt in to the steel.
Unless you have some contradictory information, Ellmer?March 25, 2014 at 10:02 pm #23236
I think we are missing the point. If you build your “floaties” right everything will just be fine. I suggest you run a couple of small scale model test on that to reach a comfort zone. In fact you need to “mess up the building and curing process really bad” to produce something that is “fragile inflexible and cracking” as you describe it here. Test it and you will see. Concrete is not mankinds most used building material due to its tremendous flaws and failurs, but due to its strength, its versatility, its good compresion and tension behavior, its forgiveness to building failure etc… it is certainly not in discussion if it is suitable to build “floaties”…March 26, 2014 at 1:04 am #23237
Ellmer, i am not debating if it is ok to build floaties with cement. Over and over again i ask about how to attach the cement floaties i will make.March 26, 2014 at 5:34 am #23238
Yes and i answered this long ago over and over again: in general when you put concrete and steel together you use welding of rebar sticking out of the piece, cast jointing, bolting, epoxi bonding, grouting, as attachment technology.
But the real good advice is: Do not “attach” anything because the ocean has its way to move and corrode attachments especially if they are not under a 3cm thick cement cover. There are much better ways to get a contious modular building approach than the “use of attachments”. Among those slip forming, dot printing, guidance layer methods, of honeycomb shells…
If you still insist in attach floaties under a steeldeck i suggest something like the foto above where you can just drill trough the upper part of the “floatie” and bolt it to a deck. To do serious float outs you need to drop the idea of putting floaties like a barril under a deck you need a “integrated honeycomb shell structure” that lasts hundreds of years and can be built to any size and specifics you need it. It is better it is more economic it is easier, it gets you more floating squaremeters per dollar. You can start such structures in canoe size and build them up to stadion size over time keeping all a integrated ongoing build. Do yourself a favor and forget the whole deck attachment method there a much better ways to do float outs.
To see more floating honeycomb shell structures check here.
http://www.pinterest.com/wellmer/oceanic-concrete-shell-building/March 26, 2014 at 6:20 am #23239March 26, 2014 at 12:49 pm #23240
Ellmer, by mentioning this link, i am not promoting it or advocating it, only saying it serves as illustration of a concept of a situation where i would be using cement instead of steel in the water:
In that company’s scheme, it’s all welded steel. A good way to attach the cement tubes to the steel platform is needed there, and i guess they have not discovered that way yet. This is also a situation it should be easy to add more beam or length to the steel deck, and “putting floaties like a barril under a deck”. Waiting until you can afford to build a single huge cast concrete honeycomb structure, or getting investors, will mean it never gets built. But someone can build a deck with a tube at each corner, and then grow the seastead as they build more floaties and more deck.
I repeat, i am not planning on doing that plan, but it is a good showing of the reason to attach cement floaties to a deck or platform that someone is already living on.March 26, 2014 at 12:54 pm #23241
There’s three of the longest floating concrete bridges in the world in the usa, one is being rebuilt now: http://www.wsdot.wa.gov/Projects/SR520Bridge/Gallery.htm . It’s not a one-piece construction.March 26, 2014 at 4:48 pm #23242
Statfjord C base honeycomb shell.
Small fiber concrete float.
Of course many different aproaches are feasible – just analyze the costs and you will see that you can build a simple shell or honeycomb structure that gives you the same amount of real estate squaremeters at 20-50 times less cost – so as long as “housing” is the purpose i see no good reason why to include expensive steel structures into a project.
You can build such honeycomb shell structures incredible big (like statfjord) as well as incredible small and everything in between you also can build andy shape you can imagine .
So where is the benefit of building complicated and expensive steel deck mixed structures as shown in the image.
The idea is to get most bang for the bug.March 26, 2014 at 5:07 pm #23243
I swear you get so dense sometimes, Ellmer. No one here can afford the first two pics, there’s no marina to launch or tie up anything like that anywhere in 100′s of miles, and i am not going to live on the the little 8x8ft bouncy thing in the 3rd picture. And i keep talking about launching small and growing, and to me the best way i can get a boat/barge built, carried to the ocean, and launched at the average marina with inteferrence is to make it look conventional in size and shape, and be easily growable after i push it to whereever the interferrence cannot see it. Frankly, i think it’s a fantastical that i am considering growing a personal seastead to 16x48ft/5x15m, but there is no way i can put anything that big in at one time, i cannot carry it, and there’s no place to launch it, or to park it. You want me to launch another Statfjord C base honeycomb, and you cannot launch a little submarine, or much of anything else? Hell, it would cost $millions just to build a new concrete plant where you want to build a new Statfjord C base honeycomb. You may as well show pictures of a base on Mars!
And you changed the 2nd picture so it’s not a concrete honeycomb anymore. I’m not editing my reply about it.March 26, 2014 at 5:14 pm #23244
I am confused what exactly is that you did NOT understand in starting canoe size and grow it from there. Please read the matrix printing thread
The big things have small beginnings thread.
The starting seasteading on small scale thread.
The ramform thread.
We have have been through that several times.March 26, 2014 at 5:35 pm #23245
The deck, and it floating, and each piece of hull you add in not bouncing independantly like a seasnake.
And i have my reasons for wanting a steel deck, at least on my first attempt at seasteading, and i already have the steel for a 16x30ft deck (and some of it is already welded together) and two 4x16ft all-steel freight barges, and i am not going to landfill the steel and it won’t sell for anything but scrap prices. The barges to haul building materials will look like people expect a boat to look, so less interference, but i want the seastead to be held up by cement floats. I have my design, my reasons, i am working on it, i plan to do it, and you can either keep telling me i am doing it all wrong, or you can be helpful.
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