PE Te
+
The basse data {er the loadings on Structure 71.1 are taken from reference 2. The curves
of maximum free-cir overpressure vs distance ard duration of postive phase vs dictance for
shot Mike of Operation Ivy are reprudscca in Figs. 2.49 an 2.50, respectiveay. The fact tnat
Structure 3.1.1 was oblique io the shock from shot Mike of Operatsen Ivy was noi considered
significant and was neglected because the angle of incidence was small (see Fig. 2.51).
An alternate variation in front-fa_e overpressure was investigated, This variation, which
includes a finite time of rise, is shown in Fig. 2.52. No attempt waz made to modify the rearface and roof loads to include the rise time because sta effect om the ivadiny: would¢ sot significantly change the structural response. The magnitude of the time of rise '.as basza on the
phenomena recorded at the site during Operauon Grecnhouse.
2.3.4
Analysis
9
j
7
ze
a3
4
f
M
4
SECRET — RESTRICTED DATA
Rene
Pe ee
IePT SET IE
SOPOT
v2
ee
Jnrinaiinc tah Sek”Sic” iadnc ahd aa chet tah chan
ssbb taeda na
dbl Ph
TY
aentheehenemmneetntagnt atest ee
The idcalized system used to approximate the behavior of Buildings 2 and 3 15 uhown in
Fig. 2.53. The multi-aegree-of-freedom actual system is replaced by 2 system having nine
independent coordinates. One coordinate is used to describe the motion of each floor mass,
bhi bits inode cated mises fellas
= (3h’/creq)
U, = velocity of propagarion of shock front
Cafe th aA 2 Mo Ld SaliHS das
pezk dynam‘c pressure generated by blast wave
Guraiion cf posilive phase of blast wave
time, measured from inatant blast wave impinges upos surface tcing -casidered
time required to clear a surface of diffraction eifects
2
=
=
=
=
‘
G,
to
t
t.
eS ERoe Tene oe He we oe en erepee en rere
The following overpressure vs time variations for windowless structures !ocated in the region
of irregular reflection obtained from reference 1 were used to compute the loadings for the
analysis of the stricture. A more compicts discussion of the theoretical and empirical basis
for these methods of load actermination is contained in reference I.
The air-blast wave in the vicinity of Structure 3.1.1 may be approximated as shown in
Fig. 2.45. The variations in front, rear, and roof pressures with time are shown in Figs. 2.46
to 2.48, respectively.
The nomenciature and reiations used in figures are:
Cy = velocity of cound in undisturbed air
Cref velocity of sound in thereflected region
422 (168 + 38% — 5)/1.6, where £ = 1 + (Py9/14.7)
h’ = clearing height, taken ag the full height of the front face or half its width, whichever
is smaller
L = length of the structure in direction of propagation of blast wave
L‘ = distance along tue roof in direction of pi opagation of blast wave to point at which
local rouf uverpressure is being calculated
Pg = maxiraum incident free-air overpressure
P, = free-air overpressure at any time t (Fig. 2.45)
Pren = reflected overpressure produced by the impingement of a plane shock on a plane
surface
= 2Pagy ((102.9 + 4P5q)/(102.9 + Pso)]
q = dynamic pressure at any time t
=q{1- (t/to)je7 35t/ty
Ode Bete
Loading
Structure 3.1.1 was located in the region of Mach reflection fur shut Mike of Gperaiicn Ivy.
vad dead
2.3.3
eh in 5
and are continuous over the entire height of the structure. Detatied sketches of Building 3 are
shown in Figs, 2,42 to 2.44,
The aralyses of Buildings 2 and 3 were carried out by using certain basic material properties. These properties with some modification are an average of those used by Ammann and
Whitney in their study of the behavior of these structures during Operation Greenhouse."' The
actual values of the pertinent quantities are presented in Table D.6,