INTRODUCTION 

 Objective 



The purpose of this study was to assess the state of the art of 

 concrete technology and construction practices as they are related to 

 the construction of massive floating structures to house ocean thermal 

 energy conversion (OTEC) systems. The relevant capabilities and limita- 

 tions of available concrete technology and construction practices are 

 described and deficient areas are identified. Recommendations for 

 research and development are given by which reasonable improvements can be 

 made in the near term to provide greater assurances of lone-term safe and 

 reliable operation of the OTEC systems and to provide lower cost 

 structures. 

 Background 



OTEC power plants are being developed to convert solar-derived 

 energy stored as heat in the world's oceans to electrical or other man- 

 usable forms of energy. Since the temperature differences between the 

 warm ocean surface waters and the cold deep waters are small, the size 

 of the thermal engines and the quantities of warm and cold water needed 

 are very large. Therefore, the OTEC power plants are not standard con- 

 struction items but represent a new type of ocean facility that has 

 never been built before: huge floating structures on the order of 

 several hundred feet in both vertical and horizontal directions. From 

 the main platform hangs a cold water inlet pipe at least a thousand feet 

 long and perhaps one hundred feet in diameter. Both moored and free 

 floating (dynamically positioned) concepts have been proposed. The 

 main platform may be a surface vessel, a semisubmersible, or a structure 



