CHAPTER II, SECTION 1 designed to resist 0.75 psi side-on and 1.5 psi reflected overpressures without temporary shoring or bracing. Dependable air-conditioning and power supply were the most important design © feature considerations to ensure protection of the electronic components of the computer from corrosive action and equipment shut-down due to powerfailure. sea-wall problem was to provide a design that would permit construction during all tide stages on the ocean reef and was resolved by using precast concrete wall sections between vertical steel H-piles. Operational requirements of the submarine cable telephone and signal systems at Eniwetok and Bikini Atolls, together with a complete ex- amination of all existing cables made at Job- site, provided design criteria for the analysis of each system to determine the extent of rehabili- tation and new installations necessary to bring the systems up to the stipulated HARDTACK capability. The new criteria included desirability of separating the communication and signal systems, both in cables and at land terminals, for safety and maintenance reasons. In addition, new signal requirements included thestipulation that an adequate number of pairs be provided to accomplish the simultaneous firing of three separate events at each atoll, with a minimum of 50 per cent of the allocated pairs as back-up. Continuity and insulation-resistant tests were conducted on 2,112,800 feet of existing cables, as follows: 5 pr. #14 oe. 549,800 feet 5 pr. #19 0. 122,400 feet 16 pr. #19 1,417,100 feet OL pr. #19 2. 23,500 feet Total... 2,112,800 feet Based on the results of these tests and the known operational requirements, an engineering (Neg. No. W-V-241-7) Figure No. 2-4. Typical Submarine Cable Vault — 50% Complete. The Multi-story Barracks, Buildings Nos. 456, 457, 459, and 460 constructed at Site Elmer, were the first two-story (128-man) barracks buildings to be built at EPG. An extensive design and cost study was prepared to determine the most feasible and economical design. The results of the study andlater investigations determined the selection of a final design having precast concrete first-story frame bents, precast flat slab second floor, all-aluminum second-story bents, and corrugated aluminum roofing and siding, This was the first use of precast concrete as an element of permanent building construction at EPG. The Airstrip Extension and Warm-up Apron at Site Fred was the largest FY 1958 PAC construction project. Design problems included de- termination of asphaltic concrete and unre-inforced portland cement concrete pavement design sections, design of a 855-foot-long concrete seawall, and newairfield lighting systems. The analysis was made and a report was submitted to the AEC containing proposals for modifications and additions to the existing cable plants. Permission to use approximately 400,000 feet of 16 pair +19-gauge submarine cable in warehouse stock at Jobsite, and authority to procure an additional 1,000,000 feet of 26 pair +19gauge submarine cable were requested. Upon approval, purchase specifications for the 26-pair 219-gauge submarine cable were prepared and procurement wasinitiated. Two types of submarine cable terminating vaults were designed, predicated on anticipated overpressures at the individual sites. Each vault contained two separate compartments, with terminating facilities in one for the telephone pairs and in the otherfor signal pairs. To ensure operation of the communications and signal systems immediately after each event, the vaults were designed as a below-grade structure with a waterproof hinged roof. Waterproof terminal boxes were positioned just below the covers in a horizontal configuration, mounted on hinged frames to allow their movement to an upright position above grade when the covers were open. This facilitated the connecting and checking Page 45