+)os
203.2
SSSEE
a
Previous Lxperiet
wo
Som? estim:tes for the damara on structures at differer.
pressure levels are given in "bffects of Atomiz Weapons"; a mre
complete table is available in Par, 5 and Table ? of "Cepabliities
of Atomic s.eapens", Department of the Army, Tech Manual TM+23- 200,
Department ef the Navy, OPNAV-P-36-00200. Department ef the Air
Fores, AFOAT 385.2, July 1951.
It should be noted thet structures fail from two
causes; from peak preesure and frem tha winds fosiowing the blast
wave,
From the standpoint of pressures, tne Mike snot presenta no
pressures much beyord present experience.
Accerding te Fig, 1; pressures
on Parry and cniwetok wilh be about 0.75 pai; pressures of G- 3 psi
were observed on Party and eniwetok from Dog and Georgs shote during
Operation Greenhouse, A presaure of 0.8 was observed on Bijiril
from Deg shot. In both cases, numereus strictures vere pvOIv eC wnilen
should furnish pertinent dsta, The reasen for this smi ine
in peak pressure is besauss the increase in yield ( Pou W 1/ } “a
offaet by the greater distance, (Elugeiab is approximately 22 miles
from Parry, compared with 9 miles on nurit.j with respest to wind
leading, ,the situation is more sericus because the positive durations scale
3, and are not offset by an increase in distance. The positive
like W 1/3
durations for 5 MT are 10 times longer than for 5 KT at the sare
distance,
2.3.3
Structures
Some gengral contiusions may be dram with regard te
structures, All ordinary window or plates giasses, especially in sizes
over 12 in. are nearly bourd te break, on Parry and sniwetok, Where
possible, walls fesing the blast wave should be removed as well as walls
directiy behind it, in order to allow pressures to build up more rapidly
within the structure, and to relieve the force from normal reflection of the
dlast. If this is not feasible ali windows and doors should be left
open, No camvas can be used unless it is strongly secured with af.
least gromnet-type fastening; plenty of sleck should be allowed,
without. taut surfaces: no large unsupported separations of canvas
should 2s draped over frams work, All tenta should be struck,
{although tents were observed to surve at Nevada Test Site at
approximately this preseure level, but much shorter duration).
The use of berms or sandbagging to protect structures is of
doubtful value; the waveform is so long that the peak pressur can
build up behind the berm before any cepreciably decay has occured;
of course, some protection is affordad from the dynamic wimi.
Small plywood structures have been observed te withstand
2 pai during some previous tests and although they failed at slightiy
higher preseures, they did ao through multiple reflections from
corners. Door frames and hinges fail readily if exposed to the
blast much above 1 psi. Holmes and Narver reports no damage
on the hanger at Lniwetcok from 0.3 psi on previow shots. At
the 0.8 psi level they report that structures bowed on a large wall facing
the blast.