Behavior of 66-Inch Concrete Spheres under Short and Long-Term Hydrostatic Loading.
Technical rept. Jun 68-Jul 71,
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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Fourteen unreinforced concrete and mortar spheres, 66 inches in outside diameter OD and 4.125 inches in wall thickness, were subjected to simulated deep-ocean loading conditions. The average short-term implosion pressure for wet-concrete spheres was 2,350 psi and for the dry-concrete spheres was 2,810 psi the average uniaxial compressive strength of the concrete was respectively 7,810 psi and 9,190 psi. Under long-term loading, the concrete spheres failed by static fatigue where the relation between level of sustained pressure and time to implosion was similar to that known for concrete under uniaxial loading. Wet-concrete spehres under seawater pressure as high as 1.670 psi showed an average DArcys permeability coefficient, K sub c, of 10 to the minus 12 power ftsec this K sub c value was also similar to that known for concrete under freqhwater pressure as high as 400 psi. Design guides were developed to predict the short- and long-term implosion pressures and permeability rates of concrete spheres. Author
- Marine Engineering