ternal ballast tanks ruptured and all were serious.y dished, resulting in some
loss of buoyancy.
The SSK-3 was submerged at periscope depth and operated
by ite crew at 18,000 ft from Wahoo surface zero. In Umbrella, the SSK-3
was unmanned and located bow-on at a range of 2900 ft. No permanent hull
deformations occurred from either shot. The following preliminary conclusions may be made:
1. A range for moderate hull damage to a submarine-like Squaw under
Umbrella conditions is 1600 ft at a depth of 50 ft.
2. <A conservatively safe range for the SSK-3 hull under Wahoo conditions {is 7000 ft at a depth of 50 ft; later analysis will permit determination
of the minimum safe range.
3. The SSK-~3 under Umbrella conditions at 2900 ft range and at a
depth of 50 feet was shown to be well beyond the minimum safe range for
hull damage.
Failure criteria for prefabricated, corrugated steel, flexible arch-shell
structures confined within non-drag-sensitive earthwork configurations of
coral sand simulating partially underground structures was studied. Three
structures were tested in the
region from
a
shot to determine empirically the response of such structures.
A fou
structure was tested in the 90-psi peak overpressure region
from a
urface shot to determine the effects of short-duration blast
loadig*on a similar structure and environment. The 25-ft span by 48-ft
10-gage arch-shell structure subjected to 90 psi peak overpressure partially collapsed on the side away from ground zero. The collapse apparently was
initiated by bearing failure of the shell plates at a bolted horizontal seam
approximately 5 ft above floor level on the collapsed side of the structure.
The following results were noted on the other three structures:
1. <A 25-ft span structure and the 38-ft span by 40-ft l-gage arch-
shell structure, subjected, respectively,
,
‘
<p>
yo
The dynamic behavior of deep (thick) reinforced concrete slabs in the
high overpressure regions of 175 to 600 psi was studied to provide the basis
for establishing design criteria for massive reinforced concrete structures
under blast loads. Thirty one-way and 15 two-way slabs mounted flush with
the ground surface were tested. The clear span was 6 feet and the ratios of
depth to span varied from 0.15 to 0.78. Because of excessive postshot radiation at the slab locations, data recovery has not been completed. However,
preliminary resulta indicate that the resistance of the slabs to high blast
pressures was considerably greater than expected.
Program 5, Aircraft Structures
-
The Air Force was concerned with determining the structural response
of a B-52D aircraft subjected to side loads. This determination had as an
ultimate objective the definition of the delivery capability of the aircraft for
multiple delivery tactics.
A range of angles with respect to ground zero
from 35° head-on to 180° tail-to in azimuth, including three different elevation
angles, were utilized in verifying the analysis and predictions.
It was con-
cluded that the data obtained were sufficient to verify the method of analysis
used to predict structural side loads from which the nuclear weapon delivery
31
SECRET
Ar WAG