Stachiw 



APPLICABILITY OF CONCRETE TO OCEAN BOTTOM HABITATS 



There are several very good reasons why concrete will find 

 application for the construction of ocean bottom habitat foundations 

 and pressure hulls containing atmospheric shirt-sleeve environment. 

 The major reasons are low cost of material, ease of forming double 

 curvature shells, strength to weight ratio (Figure 1) equivalent 

 to steels with a 45,000 psi yield point, and excellent resistance 

 to corrosion. Other reasons also important, but considered minor 

 in respect to the previously enumerated ones, are high elastic 

 stability eliminating the need for rib stiffeners in spherical hab- 

 itats for depths beyond those 100 feet (Figure 2) , excellent blend- 

 ing in with the ocean bottom making it difficult to detect the 

 habitat by hostile personnel with standard submarine detection gear, 

 and excellent resistance to underwater explosions or impacts created 

 by hostile forces. 



The thick walled concrete hulls for ocean bottom habitats 

 make it relatively easy to incorporate window, hatch, and feed- 

 through penetration flanges without additional thickening of con- 

 crete wall around the penetrations- The low heat and sound con- 

 ductivity of concrete make it unnecessary also to insulate the 

 interior of the structure against heat losses and noise emission 

 which is helpful in detecting the habitat by hostile personnel. 

 Properly formulated concrete serves also as an excellent radiation 

 shield for nuclear power generators with which future ocean bottom 

 habitats will be equipped. 



The two drawbacks that concrete possesses is its permeability 

 to sea water and tensile strength of less than 500 psi. These 

 drawbacks can be overcome by taking them into consideration during 

 the design of the habitat hull, and by the use of proper steel 

 reinforcements and waterproof coatings during the fabrication 

 process . 



Although concrete will be also used in the construction of 

 habitat foundations and columns supporting the pressure hull, all 

 of the discussion in this paper and subsequent experimental work 

 has been devoted only to pressure hulls, as they represent a more 

 demanding application for concrete. 



EXPERIMENT DESIGN 



Literature search failed to disclose any previous experimental 

 work with concrete pressure hulls under external hydrostatic loading 

 simulating deep ocean environment. Therefore it was decided first 

 to conduct an exploratory investigation into the use of concrete 

 hulls for deep ocean pressure environment to determine the avenues 

 along which it would be most profitable to direct future studies. 

 Many avenues of investigation are open in such an exploratory 

 study. Not only may different hull shapes be selected, but also 

 the composition of concrete mix, the thickness of the walls and 

 types of joints. In addition, once the hull shape has been select- 



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