structure would use lightweight concrete. However, the cold water pipe^ 

 upper portions of the structure, and congested reinforcing steel areas 

 could use lightweight concrete. 



Rapid Analysis of Fresh Concrete . Advanced development needs to be 

 conducted on equipment and techniques to analyze fresh concrete. Present 

 methods have not been field-tested and accepted to any significant degree, 

 and their processes require 15 minutes to analyze the concrete. This 

 time period should be reduced to 5 minutes, and the analyzing equipment and 

 techniques should be designed for the end application of inspecting every batch of 

 concrete placed in the OTEC structures. A program should be developed to 

 gain field experience and to validate the techniques by comparing the field 

 prediction with results obtained from standard control cylinders. 



Design 



Environmental Load Criteria . Environmental load criteria need to be 

 developed for OTEC structures. The entire structural design is aimed at 

 producing a structure with a given factor of safety under a given loading 

 condition. For ocean structures, the most difficult part of the design is 

 defining the environmental loads. Considerable effort is required on this 

 topic area, and the importance of the item is high. For example, the early 

 North Sea concrete structures were designed for a 100-year wave of 70 feet. 

 After four years of additional data collection, the size of the design 100- 

 year wave increased to 100 feet. Work is required to compile environmental 

 data on potential OTEC sites and reduce this data to loading criteria. 

 The use of probabilistic loading definition and design methods should be 

 considered. 



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