ternal-ballast tanks ruptured and all were seriously dished, resulting in some
loss of buoyancy. The SSK-3 was submerged at periscope depth and operated
by its 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 conclusiona may be made:
1.
A range for moderate hull damage to a submarine-like Squaw under
Umbrella conditions is 1600 ff at a depth of 50 ft.
2. A conservatively safe range for the SSK-S hull under Wahoo conditions is 7000 f 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 ff 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 S0- to 180-pai peak overpressure region from
a 1.4 Mt surface shot to determine empirically the response of such struc-
tures. A fourth structure was teated in the 90-psi peak overpressure region
from a 17-kt surface shot to determine the effects of short-duration blast
loading on a similar structure and environment. The 25-{ 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 shel] plates at a bolted horizontal seam
approximately 5 ft above floor level on the collapsed side of the structure.
The following resuits were noted on the other three structures:
1.
A 25-% span structure and the 38-ft span by 40-ff l-gage arch-
shell structure, subjected, respectively, to 78 and 100 psi peak overpressure
from shot Koa suffered a complete collapse symmetrically about the crown.
A third 25-ft span structure subjected to 180 psi peak overpressure collapsed
completely.
The dynamic behavior of deep (thick) reinforced concrete slabs in the
high overpressure regions of 175 to 600 pai 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 postahot radiation at the siab 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
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