RESPONSE OF BURIED CAPSULES IN THE HIGH-OVERPRESSURE REGION.
Final rept. Jan 68-Jun 69,
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CALIF
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This report describes tests of three capsule-shaped structures at the predicted 1,000-psi overpressure range in the 500-ton shot of Operation PRAIRIE FLAT. The purpose of the test program was to determine the effects of backpacking on the motions and stresses transmitted to near-surface buried structures in high-overpressure regions and to provide check data for relevant theoretical analyses. The capsules, designated C1, C2, and C3, were approximately 6 feet tall and 3 feet in diameter with 34-inch thick walls. C1 had no backpacking, C2 was backpacked with polyurethane foam, and C3 was backpacked with foamed cement. They were buried 3 feet below the surface of the ground at the same range with their axes of symmetry normal to the surface. Data from the 55 channels of electronic instrumentation showed that the backpacking reduced the peak air-induced accelerations by a factor of three and reduced the peak air-induced stresses and the relative displacements between the capsules and the soil by a factor of two. Direct-induced motions and stresses were small compared to air-blast induced stress and were not attenuated by the backpacking. The data provided checks for an empirical arching equation and a finite element computer code analysis. Author
- Structural Engineering and Building Technology