ferro-cement submarine versus conventional concrete

Originally Posted by KDB

I don’t think you need to be searched for apex1, your point of view is spattered all over these pages.
What I am a critic of is presumed guilt. It is bad logic and barbaric.
Yes, this forum is littered with “impudent amateurs” and your frustration is honestly very understandable. I feel the same about amateurs in my field.
I am sure you would find this community more to your liking if it was open only to professional marine architects and boat designers. Since that is not what the administrators intend for the forum you might want to save all of us the annoyance of you being here. I bet you could go start your own forum somewhere. Personally I would miss your bitter, spiteful diarrhea of the fingertips.
Or, and I want you to open your mind real wide here, you could grow the **** up and accept the fact that many unqualified people find your chosen field so interesting and exciting that we actually choose it as a hobby. Ergo the constant stream of dumb questions and ill conceived ideas.
Your choice of course but it seems that it does not take too much tolerance for someone to accept rock star status without contempt for the audience.

You should look one post above yours, and understand that it is not only my point of view.
None of the pro´s has a problem with "dumb" questions. We have a problem with false claims, and the ever so often showing up "supporters" of such claims.
You obviously misunderstood that.
Interesting enough, you found some of my critical, or harsh comments, but did not manage to find my advice and assistance, which is by far the majority of my contribution here. Those members that solved their problems with my assistance would hardly call my part "spiteful diarrhea". But a well established bias, as yours, is hard to kill.

Regards
Richard

[KDB]

Originally Posted by apex1

my contribution here.

Look old man, as evidenced by my attempted stealth edit above I’m done with it.
Let’s get back on topic before the mods shut down this thread too.
Lots of ferro hulls out there; seems like a worthwhile topic.
If you seriously need to keep this up meet me in the playground after class.

Regards
K

[MikeJohns]

Originally Posted by apex1

........We have a problem with false claims, and the ever so often showing up "supporters" of such claims.
..........

Yes, we go through all the design procedures and best practice to protect life and assets. We have access to knowledge refined to a high level of understanding accessible to anyone who cares to learn, or at times listen.

Some People trying and pass themselves off as experts, armchair seamen, very amateur engineers and so called naval architects who can't see the limits of their learning. Can be incredibly belligerent and deserve a much ruder response than they actually get. Particulalry when they are proposing poor practice to supporting a vested interest or a belief system.

I'd actually encourage the occasional irascible response to some of these characters .

[Submarine Tom]

Originally Posted by Submarine Tom

So the bickering and argueing continue even WITHOUT Wellmer...

"...We all live in a yellow submarine, a yellow submarine, a yellow submarine..."

-The Beatles

[MikeJohns]

Originally Posted by Submarine Tom

"...We all live in a yellow submarine, a yellow submarine, a yellow submarine..."

-The Beatles

Wilmer was the classic. He had collected half the information had half the answers and simply made up the rest.
There was a very concerning lack of engineering and calculation in his endeavor. If anyone asked him the crush depth or the factor of safety or the rated number of dives or emergency escape methods he resorted to "trust me I'm the professional who builds concrete subs" but he had no real answers.

He had some aspects of ocean engineering confused or downright wrong, not what you'd trust your life to. Like RWatson I was convinced the project would just never happen.

In reality a one atmosphere submarine is one of the most complicated expensive and most demanding vehicles you could design. It's easier to engineer a space craft than a one atmosphere submarine and a spacecraft is safer to operate and needs less redundancy.
People get carried away with the scifi fantasy.

[Submarine Tom]

MJ,

Not sure why you're responding to me on that one. You like my singing perhaps? You've simply restated the obvious.

What's your point? Where's this going? You've lost me.

-Tom

[MikeJohns]

Originally Posted by Submarine Tom

MJ,

Not sure why you're responding to me on that one. You like my singing perhaps? You've simply restated the obvious.

What's your point? Where's this going? You've lost me.

-Tom

I wasn't responding to you I was just pontificating while you were providing the backing music.

It is a serious issue though and I thought it a good idea to re-iterate the seriousness of the project before someone suggests using fer-a-light or something similarly daft.

[Knut Sand]

Originally Posted by MikeJohns

......If anyone asked him the crush depth or the factor of safety or the rated number of dives or emergency escape methods.....

shhh.... details, details.......

(come to think of it; the first "Sleipner B" platform was also a tiny bit bothered by "details" (or, more correctly; "a tiny detail" (not plural))).

Didn't this thread die?

[wellmer]

As some members of this forum have shown with their posts that they have a need to update their knowledge, i throw in a couple of pointers where to start reading.

I will not join this discussion (or any other where fastidious people are badmouthing my projects) - the info we are willing to give away is available at our website.

concretesubmarine.com

Info we do not give away is either reserved as a company know how asset for European Submarine Structures AB - or is sensitive info in the sense of ( info restriction )

------------
Concrete submarine basic reading list
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Title PREDICTING THE MAXIMUM OCEAN DEPTHS FOR SUBMERGED CONCRETE STRUCTURES
Authors Highberg, Roy Scott, Haynes, Harvey H., Civil Engineering Laboratory
Source

SPE European Petroleum Conference, 24-27 October 1978, London, United Kingdom
Copyright Copyright 1978, European Offshore Petroleum Conference and Exhibition
Language English
Preview

Abstract

This paper presents equations to predict implosion (collapse) of thick-walled concrete spherical and cylindrical structures subjected to hydrostatic pressure loading. For the spherical structures, plain concrete and steel reinforced concrete spheres are considered. The reinforcement consists of steel liners located on the inside, outside and both inside and outside of the concrete wall. For cylindrical structures, only plain concrete is considered. Figures are plain concrete is considered. Figures are presented that can be used as design charts. Example presented that can be used as design charts. Example structures, with wall thickness to outside diameter ratios defined by neutral buoyancy, are analyzed to give their maximum operating depth in the ocean.

Introduction

Commercial enterprise is looking at large undersea structures to service the offshore oil industry as it moves into deeper water depths. Quite appropriately, concrete structures are being considered for such applications as production structures, manifold structures, manned production structures, manifold structures, manned habitats, and oil storage containers. At the deep depths, hydrostatic pressure is the princip load to be resisted by the structure. Thick-walled concrete structures are required to meet the loading condition. The use of thick-walled structures has both desirable and undesirable aspects. For thick-walled concrete structures, material failure defines the implosion pressure (collapse pressure), thus full utilization of the strength of the construction material is achieved. In contrast, thin-walled structures have instability (buckling) dominated failure; here, the material is not stressed to its ultimate capacity. The undesirable aspect is that thick-walled structures are heavy. Using today's construction technology, when a structure becomes too heavy to float, the resulting wall-thickness-to-diameter ratio defines the maximum collapse depth.

The state of the art approach for the construction of massive offshore concrete structures is to build the structure in protected waters and then float it to the offshore location. In the future, methods may be developed to build massive structures on the seafloor. At that time, it may be desirable to build structures which are designed for negative buoyancy. Deeper depths for concrete structures will be an outcome. The purpose of the paper is to present a simplified design purpose of the paper is to present a simplified design approach to predict the implosion strength of thick-walled concrete spheres and cylinders. The end objective is to summarize information on the maximum depth in the ocean that pressure-resistant concrete structures are likely to be used.

THICK-WALLED SPHERES

Thick-walled spheres are defined as those spheres having a geometry in which material failure controls the implosion pressure. For concrete spheres this geometry occurs at a t/Do of about 0.02.

The design approach for predicting implosion of thick-walled spheres is based on the average wall stress at implosion. From implosion test results it was apparent that spheres withstood wall stresses at implosion, sigma im, greater than the uniaxial compressive strength, f'c, of the concrete. The average wall stress was used because observed crack development in the wall prior to implosion resulted in redistribution of stresses across the thickness. The average wall stress at implosion is expressed as:

(1)

P. 233

source
http://www.onepetro.org/mslib/servle...008066&soc=SPE
-----------------------------------------------------------------
Paper Number 3011-MS
Title OCEAN IMPLOSION TEST OF CONCRETE (SEACON) CYLINDRICAL STRUCTURE
Authors Roy S. Highberg and Harvey H. Haynes, Civil Engineering Laboratory
Source

Offshore Technology Conference, 2-5 May , Houston, Texas
Copyright 1977. Offshore Technology Conference
Language English
Preview ABSTRACT

An ocean implosion test was conducted on a pressure-resistant concrete cylindrical structure to obtain the depth at implosion. The structure was a reinforced concrete cylinder with hemispherical end caps, twenty feet (6.1 m) in overall length, ten feet (3.05 m) in outside diameter, and 9.5 inches (241 mm) in wall thickness. The structure was near-neutrally buoyant having a positive buoyancy of 12,000 pounds (5.4 Mg) for a hull displacement of 85,000 pounds (38.5 Mg). The implosion depth of the cylinder was 4700 feet (1430 m). A predicted implosion depth, using an empirical design equation based upon past test results, was 16 percent less than the actual implosion depth.

INTRODUCTION

A pressure-resistant, reinforced concrete hull was constructed in 1971 as part of a Seafloor Construction Experiment, SEACON I. The structure was placed on the seafloor at a depth of 600 feet (180 m) for 10 months. Figure 1 shows the SEACON I hull prior to its ocean emplacement. Since its retrieval in 1972, it has been located in the open air about 150 ft. (50 m) from the ocean. In the summer of 1976, the structure was returned to the ocean for an ultimate load test, that is, the structure was lowered into the ocean until implosion.

SPECIMEN DESCRIPTION

The cylindrical structure was assembled from three precast, reinforced concrete sections. The straight cylinder section, 10.1 feet (3080 mm) in outside diameter by 10 feet (3050 mm) in length by 9.5 inches (241 mm) in wall thickness, was fabricated by United Concrete Pipe Corporation. The concrete hemisphere end-closures, 10.1 feet (3080 mm) in outside diameter by 9.5 inches (241 mm) in wall thickness, were fabricated in-house. Tolerances on the sections conformed to concrete pipe standards of not to exceed to ±0.75 inch (19 mm) for the inside diameter or minus 0.5 inch (13 mm) for the wall thickness.

Steel reinforcement in the amount of 0.70% by area was used in both the axial and hoop direction. Reinforcing bars of 0.6 inch (15 mm) diameter were employed throughout the structure. A double circular reinforcement cage was fabricated for each precast section; the concrete cover on the outside and inside reinforcing cage was 1 inch (25 mm). For the cylinder section, hoop rebars had a spacing of 27.25 inches (692 nm) and 31.25 inches (794 mm) for the inside and outside cages respectively.

The hemispherical end-closures were bonded to the cylinder section with an epoxy adhesive, no other attachment besides the epoxy bond was employed (Figure 2). The gap between the mating surfaces of the hemisphere and the cylinder was less than 0.13 inch (3 mm) for 75% of the contact area. Prior to epoxy bonding, the concrete surfaces were prepared by sandblasting and washing with acetone.

Source: http://www.onepetro.org/mslib/servle...011-MS&soc=OTC

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---------------------------------------------------------------
XIV National Conference on Structural Engineering,
Acapulco 2004

Offshore Structures - A new challenge

Knut Sandvik, Rolf Eie and Jan-Diederik Advocaat, of Aker Kvaerner Engineering & Technology AS, Arnstein Godejord, Kåre O.Hæreid, Kolbjørn Høyland and Tor Ole Olsen, of Dr.techn.Olav Olsen a.s - Norway

Link:
http://www.tekna.no/arkiv/NB/Norwegi...Structures.pdf


..References

[1] Morgan, R. G. Development of the concrete hull. "Concrete Afloat", Proceedings of the
conference on concrete ships and floating structures organized by The Concrete Society in
association with the Royal Institution of Naval Architects and held in London on 3 and 4
March, 1977.

[2] Gloyd, C. S. Concrete Floating Bridges. Concrete International, May 1988.

[3] Anderson, A. R. Design and Construction of a 375.000 bbl Prestressed Concrete Floating LPG
Storage Facility for the JAVA Sea. Offshore Technology Conference, OTC 2487, 1976.

[4] Sannum, H. Heidrun, The First Concrete TLP. The Future Development of the North Sea and
Atlantic Frontier Regions. OCS, Aberdeen 25 and 26 January 1995.

[5] Ruud, M. The Troll Olje Development Project. Vision Eureka, New Technology for Concrete
Structures Offshore. Lillehammer 13 & 16 June 1994

[6] Valenchon, Nagel, Viallon, Belbeoc’h, Rouillon: The NKOSSA concrete oil production barge.
OMAE 1995 - Copenhagen - 14th International conference - June 18-22 1995.

[7] Valenchon, Nagel, Viallon, Belbeoc’h, Rouillon: The NKOSSA concrete oil production barge.
Paper presented at DOT, 30 Oct. / 1 st Nov. 1995, Rio de Janeiro, Brazil.

[8] Sare and Yee Operational experience with pre-stressed concrete barges "Concrete Afloat",
Proceedings of the conference on concrete ships and floating structures organized by The
Concrete Society in association with the Royal Institution of Naval Architects and held in
London on 3 and 4 March, 1977.

[9] Fjeld (NC), Hall (Phillips), Hoff (Mobil), Michel (Doris), Robberstad (Elf), Vegge (Norw.
Petrol. Directorate), Warland (Statoil): The North Sea concrete platforms - 20 years of
experience, OTC 1994, Houston

[10] Bech, S., Carlsen, J.E.: "Durability of High-Strength Offshore Concrete Structures".
Proceedings - 5th. International Symposium on Utilisation of High Strength/High Performance
Concrete. Sandefjord, Norway, June 1999.

[11] Derrington, J. A. Prestressed concrete platforms for process plants. Proceedings of the
conference on concrete ships and floating structures organized by The Concrete Society in
association with the Royal Institution of Naval Architects and held in London on 3 and 4
March, 1977.

[12] Morgan, R. G. History of and Experience with Concrete Ships. Proceedings of the conference
on concrete ships and floating structures, Sept. 15-19, 1975 / Berkeley, California, Ben C.
Gerwick jr. Editor.

[13] Nanni, A. and Lista, W.L. Concrete Cracking in Coastal Areas: Problems and Solutions.
Concrete International, Dec. 1988

[14] FIP (Federation Internationale de la Precontrainte) state of the art report: The inspection,
maintenance and repair of concrete sea structures, August 1982

[PAR]

Is it me or have there been a rash of old threads revived, with seemly innocuous questions, but end up favoring the ridiculous or unsubstantiated? It just seems this has been occurring a lot, especially in the concrete threads, though other "hair brained" stuff has been visited lately.

So, Wellmer is your safe dive depth determined by engineering or simply if the product makes it to the US coast undetected?

Okay, I'll go back to humming while Tom finishes up the backup vocals.

[Submarine Tom]

Thanks for clarifying MJ, glad you like my singing.

Willy's back! I'm outta here...

-Tom

p.S. Before I go. Friends of yours Willy? http://colombiareports.com/colombia-...ubmarine-.html

[wellmer]

as said in the previous threads

Submarine Yacht project


Concrete submarine

...it makes little sense for me to fuel forums dedicated to badmouth my projects with my presence - so i will let go this thread (and his fastidius participants that will not allow me to have a quality discussion) down the drain as it deseves...

[MikeJohns]

Will

You'd get nothing but support if you did this sensibly but look at your responses.

You just post some marginally related papers and point to your website. That approach raises serious questions and concerns. When you are asked about serious issues your response is the classic post above.

Your threads have shown you to have a lot of misconceptions misunderstandings and oversights and the more you responded the more you made your lack of knowledge apparent. Isn't that the main reason for this predictable response?

If you can't answer simple technical questions in the design and construction phase, how will you answer them when it's operational?

You don't have a robust peer reviewed design and every technical question catches you on the hop. Your response is predictable which is a shame, I for one would have been very interested in the technical discussion.


The forum member LyndonJ has performed detailed FEA analysis of hollow steel reinforced concrete structures and has a postgrad thesis on the subject. He could give you a crush depth for a consult fee of a few thousand dollars I would expect. I'll see him tonight at an engineers meeting, (those professionals you like to hang off the coat tales, but don't want them to scrutinise your project).

Here's your engineered estimate and detailed calculation:

Originally Posted by wellmer

My submarine prototype - which i obviously did not test to destruction depth - has almost exactly the double diameter / wall thickness as troll - means it is double as strong and may have a destruction depth of 1212m -

And you wonder about our concern

[tugboat]

Originally Posted by wellmer

as said in the previous threads

Submarine Yacht project


Concrete submarine

...it makes little sense for me to fuel forums dedicated to badmouth my projects with my presence - so i will let go this thread (and his fastidius participants that will not allow me to have a quality discussion) down the drain as it deseves...

Wil- i dont know how this ended up getting you involved--it was just a question for those of us believers out there...i offer my apologies.
if i could close the thread i would..

[RHP]

Good news lads, theres a sub engine available on eBay !!

http://cgi.ebay.co.uk/Vickers-Armstr...item35adbfe1c8