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,