CONCEPTION, DESIGN, AND SITE CRITERIA 



The initial action to consider procurement of a tower was 

 a memorandum by the author (Memo 2242-49-55) of 29 June 1955 

 which pointed out the advantages of such a facility to the Labora- 

 tory's mission. It also contained a preliminary structural draw- 

 ing of the tower. At that time it was difficult to obtain and use 

 ships for shallow-water oceanographic and acoustic work. 



The proposal was carefully reviewed at the Laboratory and 

 the Bureau of Ships. Funds were budgeted and eventually approved 

 for final design and construction. 



The contract to prepare plans and specifications for con- 

 struction of the oceanographic tower was awarded on 18 April 1957 

 to Moffatt and Nichol, Inc. , Consulting Engineers, Long Beach, 

 California by the Bureau of Yards and Docks. 



After selection of the site (approximately 0. 8 mile offshore 

 from Mission Beach) exploratory studies of the subbottom were 

 made by the Rand Corporation. Jet probes and drilling techniques 

 were used to produce a 63-foot vertical picture of the subbottom. 

 From this information it was determined that the tower could be 

 anchored to the sea floor with 63-foot-long steel pins. 



The tower construction contract was let to McDonald Con- 

 tractors, Inc. , Los Angeles on 17 November 1958. Construction 

 was completed 2 July 1959. 



Sample Depth 

 (Ft) 



Soil Type 



Type of 

 Test* 



Surcharge 

 (Lbs/sq ft) 



17 



Medium to 

 coarse sand 

 and shells 



F 



700 

 1,200 



25 



Coarse sand 

 and shells 



F 



1,000 

 1,500 



41 



Silty loam 



DS 



1,500 

 2,000 



41.5 



Silty loam 

 with fine 

 sand 



F 



1,500 

 2,000 



58 



Coarse sand 

 and shells 



M&D 





*F = Friction tests on steel; DS = Direct shear tests; 

 M&D = Moisture and density determinations. 



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