CHAPTER 5.11 TOWERS Engineering work to provide the facilities for the scientific program and experiments at the Eniwetok Proving Grounds was very extensive and re— quired the solution of many unusual engineering problems. Furthermore, the criteria were supplied piecemeal, starting in September 1948 and continuing until December 1950. J-Division coordinated the requirements of the various scientific agencies involved, and Holmes & Narver supplied the engineering designs to meet these requirements. 300_ FOOT TOWERS In a series of meetings at Los Alamos, September 12 to 18, 1948, group discussions were held as to the philosophy of coming tests. One such meeting concerned the criteria for design of scientific structures and another such meeting concerned the requirements, both scientific and structural, for the design of towers, The design of towers was of particular concern to J-Division personnel because the uncertainties of design, manufacture, and erection for the sort of towers then contemplated would leave no time to lose if the proposed 1951 test schedule was to be realized, It was also important to the scientific development going on to know whether practical engineering limitations existed to the scope of experiments cesired by varlous groups. Studies were therefore started concurrently witn the departure of the reconnaissance party to examine the Project site. At the Los Alamos meeting on towers, it was stated by a group leader that it was desirable for the new experiments that the towers be at least 250 feet in height. The towers used for Sandstone had been 200 feet high and free standing. It was stated that the 250 foot height was a minimum and greater height would be highly desirable, It was developed that the hesitation on the part of the scientists for going higher was that they thought that the higher towers would require such a great amount of steel that it would affect the results of their experiment by introducing so much ferrous material into the clouds. H& N suggested that this might be overcome by the use of a guyed tower which would require a very much smaller quantity of material and that almost any height that would be satisfactory to them could be obtained. It was determined that the guys would not be detrimental to the experiment if they were kept down a proper distance from the top of the tower, The result of this meeting was an agreement to make some comparative preliminary designs to determine the amount of material in guyed towers versus free standing towers. The H & N representatives pro- posed that if the space planning could be arranged to suit the test require- ments, a triangular tower would probably be of advantage over a square tower in that there would be less material required. Comparative studies for towers started immediately, and these studies were presented to J-Division. In the meantime, it had been developed that a triangular tower could be built that would be entirely satisfactory. The tower design was developed entirely within the Holmes & Narver Engineering Division. Considerations of feasibility, mass, and adequacy 5128