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AW: [PSUBS-MAILIST] concrete Submersible ?
hi
I just wanted to thank you guys for your pretty useful hints on concrete
Sub's.
I my self have used concrete successfully on concrete canoe's for the German
concrete canoe race for already 2 times.
Concrete has become a very cool material in these last years and so we
accomplished for example on the 1. Cano I worked on a 3mm (1/8") concrete
shell that was only supported by the thicker border on top of the Cano.
The whole 4m (13'1-1/2") long and 70cm (2'3-1/4") wide canoe weights only
about 27.5kb (55 pound) and that I believe is quite cool. The trick is not
to use steel reinforcement but fiber.
But the difficulty is to get fiber that is resistant to the chemical
processes in the concrete. (by the way I believe they are the same chemical
processes that prevent steel rebar's from corrosion [yes, it is impossible
for steel to rost if enough concrete surrounds it, no matter how much O2 or
H20 get to it because of the Ca(OH)2])
And the other trick is to use modern high strength concrete.
But cheap is concrete is really not cheap, quite the opposite ! The fiber
turns out to be the most expensive part if you can get some at all since it
is till now only used in research (as far as I know).
To calculate the compressive resistance of such an concrete shell might turn
out to be quite difficult, thought not impossible. All I can say is that on
some prestressed concrete canoe we mad we tested one of the elements (70cm
wide, 50cm long, 4-5mm thick) and got the failure at 36kN (about 72kp or 2
BMW's) (you can see the documentation at
http://fsrbiw.myip.org/~betonboot/kanu2000/homepage.htm thought it is in
German) this equals just 9 Mpa Axial stress and is far below the 40Mpa that
should be possible but this is due to buckling.
So... I hope, I didn't bothered you to much, just wanted to show what
concrete is today. (and during my research of the archive I figured that
there is only little know about concrete)
so long
Marko
-----Ursprüngliche Nachricht-----
Von: owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org]Im Auftrag von Carsten
Standfuß
Gesendet: Samstag, 19. Januar 2002 10:47
An: personal_submersibles@psubs.org
Betreff: Re: [PSUBS-MAILIST] concrete Submersible ?
Hi Makro nice to here from you:
First : go to
http://popularmechanics.mondosearch.com/cgi-bin/MsmGo.exe?grab_id=8189952&EX
TRA_ARG=&CFGNAME=MssFind%2Ecfg&host_id=1&page_id=7006&query=concrete+submari
ne&hiword=CONCRETE+SUBMARINE+CONCRETES+SUBMARINES+SUBMARINERS+SUBMARINER+
Second :
I have here commerzial proposal of 1994
Ellmer Wilfried
Hauptstr.17 C
A -2344 Ma.Enzersdorf
Tel.: 02236 49952
Österreich
He ha s allready build at least one submarine hull made from concrete:
Hull form like airship or blimp
Length : 9,0 m
beam : 2,4 m
Hull tickness between 18 cm - 8 cm (1/12 of the local hull diameter)
Weight 15 t
Upright high inside : 195 cm
Porthole diameter : 50 cm
Surface : Painted with GRP and Tear
concrete tenisle : 225 kp/cm2
Armierung : 6 mm Steel roundbar welded likea fishernet all 10 cm
in the middle axis of the wall tickness.
Destroy deep : 400 m (I am not shure how to calculate that..)
Maintance cost for hull each year : about 50 euro
Basic price for only hull : 22.000 euro (1994)
His first hull was for two years in the Attersee (Atter lake)
in Austria without any damage - and he wrote that this was a full
operable submarine - his pictures shows just the hull very high
out of the water.
I don't know if he is still in bussiness, I never contact him,
The hull itself and the description of the hull looks great
- the technology description of the submarine technic
is a little poor - obviously he is a man of concrete.
third:
At the "Deutsches Schiffahrtsmuseum - Bremerhaven" in the outdoor
area is a tug displayed - hull complete made from concrete.
(Wilhelm Bauer a XXI, and a Seehund, and a full Walter Plant submarine
section are also in these museum.)
Obviously - cold weather under 0 degree (frozzen) is a problem foor
this kind of hulls.
I think it can be a cheap material to build sub -
but I will not use it until - somebody over math.calculation and test
bodys,
shown how to calculate the crush deep of a composite concrete hull.
But maybe some engineer which normaly design "Autobahn" bridges
has allready the right figures.
best regards - Carsten near Bremen
Marko Thiele schrieb:
>
> hi,
>
> My Name is Marko Thiele and I'm new to this mailinglist. I just thought to
> introduce myself. I'm from Germany and an structural engineering student
at
> the Dresden University of Technology.
> The following question I got for you folks might not sound very smart, but
> I'm serious and hope for an serious answer.
> So here it is.....
>
> does anyone of you know if anyone has ever attempted to build a
Submersible,
> Submarine or similar out of concrete ?
> (yes, I mean indeed this rock like material)
>
> If anyone knows something about this, or thinks he knows that this has
never
> been done, I would love to here from him.
>
> so long...
> Marko