CHAPTER II, SECTION 2 activities occurred. Through somesacrifices by User personnel in shortening oeneficial occupancy time and partially eliminating their pre-test dry runs, all stations were readied in time. This may be noted from Figure 2-3, which indicates that by 1 May 1955 much ofthe lag in progress had been overcome and that the schedule for scientific Test facilities was essentially met. The construction progress of permanent base projects is shown in charts at end of this discussion. Due to the urgency that developed in construction of expendable test facilities, it became necessary to concentrate men and equipment on this work and to defer the con- struction of less vital permanent base projects. Therefore, the actual progress attained on overall permanent base construction was not in phase with predicted progress. However, when men and equipment could be spared from work on scientific facilities, the work on deferred projects was undertaken again. away from the main bases throughout the construction period as the supporting vessels made only one call at each site. The over-all problem was overcome by carefully planning equipment usage for the construction phase of each structure with the idea of utilizing all equipment. This involved a considerable movement of equipment between sites in order to meet require- ments. It also necessitated rigid scheduling of the various crafts in order that placement of reinforcing steel, and electrical, mechanical, and other related items would fit the plan for equipment usage. Extensive construction activities were re- quired on the reefs at both Eniwetok and Bikini Atolls. Tidal conditions and weather were important factors. To overcome the difficulties inherent to working in sea water of varying depths, various measures were employed. Concrete was precast where practicable. In some cases forms were prefabricated, then set at low tide, and concrete was poured using tremies. Equipment had to be serviced frequently and even with the most thorough preventive main- tenance, salt water action seriously impaired its life. To reduce shutdowns because of breakdowns, mixers of two transit-mix trucks were removed from their chassis and installed on trailers. Wagon drills and compressors used in aggregate production and a crane used for pile driving were similarly mounted. This not only reduced breakdowns but permitted work to proceed on the reefs for longer periods. tay During December 1955, the Proving Ground was subject to heavy seas, which periodically occur in this area. This caused considerable damage to construction in place on the reefs, the deadlining of some heavy equipment, and the loss of a number of small tools. These conditions occurred during a period of intense activity. By concentrating men and equipment on the affected projects, the temporary setback in progress caused by these high seas was overcome without © a serious effect on the over-all program. Figure 2-17. Placing Planking for Bulkhead One of the most difficult problems experienced was that of scheduling the use of con- struction equipment, since sufficient equipment was not always available to adequately outfit the construction crews at each site. This was especially true of concrete-placing and welding equipment, trucks, cranes andtrailers. Of parti- cular significance in this respect was the requirement for such equipment at off-atoll construction sites. This equipment had to remain Page 2-18 Exploration was made early in the program to determine suitable sources of coral aggregate; possible reef locations were selected from samples tested by the Field Engineering Force. As the aggregate was generally obtained from these reef locations, the rate of production was necessarily slow due to normal difficulties encountered in subaqueous excavations. The use of wagon drills and compressors mounted on trailers permitted operations to proceed at higher tide levels than normally possible had standard wheel-mounted wagon drills been used. To ensure maximum production with minimum op- erational interference, all blasting was performed after the regular working day. Stockpiling of the aggregate was both logical and economical. The testing laboratory made two gradation checks on each day’s operation to ensure that aggregate was within specified gradation limits.