/ 



MCH08 CONCEPTS DEVELOPED 



Si&e and Loading Conditions 



The assumed site and anchor loading conditions are based on two 

 quite different environments: (1) a benign, deep ocean environment and 

 (2) a demanding, Gulf Stream environment. Also, the loading conditions 

 are based on two different sets of plant size and mooring configuration 

 with (1) one set applied during study Phase I, for the selection of 

 anchor types, and (2) a second, less-all-inclusive set applied during 

 study Phase Ila, for the selection of anchor installation techniques. 

 An explanation of the differences in the assumed loading conditions 

 follows. j 



P hase I ■ In the deep ocean environment, water depths range from 

 2,000 to 6,000 m (6,000 to 20,000 ft). The seafloor material is calcar- 

 eous ooze or pelagic clay. Wind and current load on the power plant was 

 estimated to be about 9 HN (2 x 10 lb) [4,5]. For the Phase I effort, 

 a safety factor of two was applied, yielding an ultimate horizontal 

 component of mooring line load at the anchor of 18 MN (4 x 10 lb). The 

 mooring line angle with the horizontal was assumed to range from to 

 1.4 rad (80 deg) , depending on the mooring system design (Figure 1). 

 Raising the mooring line angle from the horizontal introduces a vertical 

 load component at the anchor. At a mooring line angle of 1.4 rad, this 

 vertical load component amounts to 100 MN (23 x 10 lb). 



In the Gulf Stream environment, water depths expected are about 500 

 to 1,000 m (1,500 to 3,000 ft). The likely seafloor material is sand, 

 gravel, or rock. Loads on the power plants in the Gulf Stream environ- 

 ment are approximately 10 times those in the deep ocean environment 

 [4,5], resulting in an assumed ultimate horizontal component of mooring 

 line load at the anchor, with a safety factor of two, of 180 MN (40 x 10 lb). 

 For this environment, the mooring line angle with the horizontal was 

 assumed to range from to a maximum of 0.8 rad (45 deg), depending on 

 the mooring system design (Figure 2). The vertical load component 

 corresponding to a line angle of 0.8 rad is 180 MN (40 x 10 lb). 



