concrete is several times that of regular concrete. 



Damaged sections of the concrete hull can be repaired by removing 

 cracked or crushed concrete from the damaged area. Reinforcing or pre- 

 stress steel is exposed so that new reinforcement can be attached by 

 welding or mechanical means. Prestress steel can be stressed to proper 

 levels by jacks or screws. New concrete is cast in the damaged section. 

 Similar repair procedures have been conducted on concrete ships and 

 vessels built in WWI and II. Recently, the Italian government required 

 that repair procedures be proven effective in returning a concrete dry 

 dock to its original conditions of strength before approval was granted 

 to build the drydock.L 51 J Repair methods were proven for reinforced and 

 prestressed concrete and the drydock 1S presently under construction. 



Buoyancy Changes . Buoyancy changes in an OTEC concrete structure 

 can occur from animal and vegetation growth on the structure. One cause 

 for buoyancy change that is special to concrete is water absorption with 

 time. The designers of the structure must incorporate means for adjusting 

 the buoyancy as water is absorbed into the concrete. 



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