Construction 



Construction Methods . Three approaches are available for the con- 

 struction of large concrete structures: (1) slip-forming, or similar 

 methods in which the concrete is cast in an essentially continuous manner 

 without construction joints; (2) conventional sequential concrete pours 

 with water-stop cast in the construction joints (or other waterproofing 

 methods used); and (3) joining precast elements together to build the 

 main structure or subassemblies which are then in turn joined to each 

 other or to the structure. 



Construction Sites . As described above, construction is usually 

 started on land and then continued afloat. The critical i£em for con- 

 struction of OTEC structures is the availability of deep, protected 

 waters for the construction site and natural deep waterways leading to 

 the open ocean. For OTEC, the water depths may need to be as great as 

 400 feet. A preliminary search for construction sites in United States waters 

 found no such sites. If none are available then other construction 

 approaches will have to be developed, such as reusable auxiliary flota- 

 tion structures to supply buoyancy in shallow waters or the use of 

 modular assembly in the deep but less protected waters. 



Political considerations, effects of which are not known at this time, 

 may also strongly influence construction site availability. States such 

 as California have legislation for the conservation of shoreline that 

 might prohibit the construction of new flooding basins. 



Other Considerations . Manpower, construction materials, and construction 

 equipment are available and in abundant supply for building OTEC structures. 



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