atructural damage was discerned. See Figs, 2.6 to 2.8 for pretest views and Figg. 2.9 and 2.10 for posttest views. (b) Building 2, The back-wall corrugated metal sheathing cn Building 2 was deflected inward between supporting beams. The large deflection of the sheathing caused the girtflanges to become distorted and twisted. This building was obviously deflected away from the blast, but the main supporting steel columns remained undamaged except for plastic rotation of their ends, The roof was undamaged. See Figs. 2..1 and 2.12 ior pretest views and Figs. 2.13 and 2.14 for posttest views. (c) Building 3, Building 2 was deflected away {rom the blast in 2 manner similar to Building 2. The concrete cclumns were crackeu and apalled at the top and bottom owing to plastic hinge action. The roof was essentially undamaged, Pretest photographs are shown in Figs. 2.15 and 2.16; the only posttest views available are in Figs. 2.9, 2,10, and 2,13. ANT (e) Buslding 5. The rear wall of Building 5, which had been badly damages by the Easy shot of Operation Greenhouse, was destroyed by Operation Ivy. The wall slab was detached at the roof and floor levels and rotated about th~ top of the footing until it lay tiat on the ground at the rear of the structure. Except ‘or the lateral deflection of the structt+, no additional damage waa noted. Pretest views c. Building § are given in Figs. 2.27 ana <.28, and posttest views are given in Figs. 2.26 io 2.21, Fe id) Building 4. Building 4 was undamaged with the exceptior of the roof. Large cracks were opened in the roof slaba adjacent to the shear walls and roof girders, On the underside of the roof these cracks appear to be located along the ends of reinforcing Lara placed in the bottom of the roof slab aud terminating about 3.3 in. from waits and girders. These bars are oriented normal to the shear walls. The roof cracks originated in Operation Greenhouse {ullowing the Item shot and were widened by Operation Ivy. Several interior views uf Budding 4 are given in Figs. 2.18 to 2.26. Exterior views of Butiding 4 are shown in Figs, 2.9, 2.10, 2.17, 2.29, and 2.34, (f} Buildings 6 and 7, Sulidirgs 6 and 7 received no apparent damage beyonra [hit observed in previous operations, Pretest ard ;osttest views of these buildings are containcd in Figs. 2.32 to 2.38. 2.3 2.3.1 DYNAMIC ANALYSI3 Uf STRUCTURE 3.1.1 Introduction Section 2.3 deala whi. ike general features cf the analysis of Bullaings 2 aud 2 of Structure 3.1.1. Attention 15 given to the over-all struciural configuration, the fancanertal load vs time variations, and the bagic concepts used tc turmulate and solve the equiticng of motion. Methods for evaiuating reSouad and aetcrmintng frt-ce -< tistances are adopted on the basis of an investigation of data from Cpe. ation Greenhouse. The cesuita Uf the varjoiz analyses are presented in graphical fors:. 2.3.2 Structural Properties Building 2 ts a three-atory steel-frame structure, one bay wide and three bays long. The structural frame consists of two rigid {frames constructed of standard rotied sections throvghout. Welded connections ace used to ensure continuity at all the Joinia of the frar . The coof and foors are one-way reinforced-concrete slabs sr*nning betweea frames. Steel V-beam sheeting is used as the covering material fur the front ard rear faces, The V-vcau ts supported on girts of standard roiled sections which span between floors, Detailed sketches of Building 2 are shown in Figs. 2.39 to 2.41. . Building 3 (g a three-story reinforced-concrete frame structure, one bay wide and three bays long. The roof and floors are one-way reinforced-concrete slabs spanning between frames. The front and rear faces are one-way reinforced-concrete slabs spanning vertically 18 dM La SECRET - RESTRICTED DATA