CHAPTER If, SECTION 1 further modification of prepared design drawings for adaptation to the new location. The Service Tower, Station 6001, as first designed for Site How was a 90-foot-high, cor- rugated metal-covered, steel-frame structure, 24 feet square in plan, and was mounted on steel wheels for mobility on tracks. When this tower was later constructed at Johnston Island, the roof structure, sliding door, and tower siding were omitted and the foundation was redesigned to minimize procurement and construction time. The basic design problems were to provide a structure meeting the User’s several detail requirements: stability in motion in a 30-mph wind; resistance to a wind pressure of 30 pounds per square tuot when in fixed anchored position; provision for a system to move the standing Station 2250 at Site Sugar was the first requirement for a non-expendable, blast-resist- ant, steel, guyed tower structure at EPG. Essentially, the station tower was a 150-foot tower guyed at the top level and made up of 25-foot segments of a standard 300-foot shot tower de- veloped for EPG. An unusual aspect of Station 2250 was that it was supported at its base on the roof level of the Room D addition to existing Station 2200; this was also the first time at EPG for the erection of a significant steel tower upon a Scientific Station structure roof. The IBM Building, No. 453, designed to house a model 707 IBM computer system, was the first fireproof re-inforced concrete office build- ing to be constructed at EPG. The structure was structure to and from the firing and parking pad; ability to enclose the standing missile on all sides; and stability in resisting overpressures from the first events in Bikini Lagoon with the metal siding removed. The problem when first confronted seemed overwhelming and of doubtful feasibility because of the great size of the structure. Design was not particularly difficult from the engineering standpoint, but problems arose as a result of the unusual details for hinged platforms at tower work levels, tower tie-down anchors at the parking and firing pads, concrete counter-weights at the lower platform level, and the towing system rigging and winch. Pinex-type Barge Zero Stations were an entirely new type of barge modification develop- ment. The general configuration of the deck structure details, underwater collimating pipe, and access caisson were as suggested by the Users. The main design problems werein selecting design and details for an adequate and feasible bracing system support of a long, large- diameter, steel pipe below the bottom of the hull, the vertical removable steel caisson for access to the underwater lower end of thecollimating pipe, and a multitudeof details for underwater connections and water-tight joints. The barge facilities at Site Nan were more in the order of an unusual facility rather than a difficult design, once the over-all general planning concept was determined. The design objective was to provide two quiet-water, barge-mooring slips for outfitting shot barges. The gate construction to prevent water level surge in the two basins was the basic problem. The under- water gate sill construction initially suggested an obstacle, but this was surmounted by plan- ning to drive steel sheet-piling, cut-off walls topped with a level steel section. This was later revised during the construction period to provide a prefabricated sheet-pile, cut-off wall section lowered into an underwater excavation, back- filled and tied off by wire rope. Page 44 (Neg. No. W-V-243-5) Figure No. 2-3. Caisson Installation on Pinex Type Barge.