The interior dimensions are approximately 90 by 90 feet, with the centerline of the ramp radial to ground zero. The structure had a 30-inch roof slab which was supported by 9 columns and was covered with 3 feet of earth to attenuate the nuclear radiation. (See slide No. 32.) SLIDE NO. 32.-Construction view of underground garage and shelter. A 100-ton reinforced concrete door about 4 feet thick was provided to give protection from radiation and to provide a pressure seal. After receiving approximately 40 pounds per square inch, the only apparent damage to the garage was that of breaking away the end retaining wall and cracking the side retaining wall of the ramp. (See slide No. 33.) The results indicate that occupants of the shelter would |