Increases in ultimate strengths of 23.7 (Series I) and 24.6 (Series II) percent under dynamic loading were obtained. Theoretical slab strengths were determined. Modification of the equations used allowed good predictions of tensile membrane resistance of the static slabs. The equations were used to predict peak pressures sustained by the dynamic slabs.

This study was conducted in support of the Defense Civil Preparedness Agency's (DCPA) Crisis Relocation Planning (CRP) program in which existing structures will be upgraded to provide fallout shelters for a relocated population. A demonstration test was conducted in which a residential dwelling was upgraded by placing soil against the walls and on the roof of the structure. The shelter was large enough to house 80 people. Upgrading was accomplished partially by hand labor and machinery. The test showed that a conventional structure could be upgraded and that the shelter occupants using tools and materials found in most homes could if necessary upgrade their shelter during the expected 2- or 3-day period of crisis relocation preceding a nuclear attack.

The objective of the study reported herein was to determine the response, up to collapse, of a conventional floor and framing system typical of the systems which would be located over a basement fallout shelter in a steel frame building. Static and dynamic tests were conducted on two 1/4.5-scale models of the basement shelter area from a multistory steel frame prototype structure designed for this study.