Where 



g = gravitational constant 



T = wave period 



it = 3.14 



d = local water depth 



Given the wave climate, it is pertinent to remember that the average waves are 

 not the ones which contribute to the destruction of the breakwater. The peak 

 waves or the care, extreme occurrences are the parameters the structure must 

 be designed to withstand. Once the incoming wave climate has been ascer- 

 tained, the acceptable wave heights which can be tolerated in the sheltered 

 area must be determined. When the acceptable transmitted wave has been deter- 

 mined, the transmission coefficient is fixed. 



b. Anchoring Systems. As discussed by Giles and Eckert (1979), the type 

 of system selected for anchoring a floating breakwater depends on the peak 

 mooring forces estimated for the structure, the bottom conditions at the site, 

 and the methods available for installing the anchor. The two most commonly 

 used methods for anchoring any type of floating breakwater are the deadweight 

 anchor and the pile anchor. Embedment anchors and screw anchors have had 

 limited use, primarily because they have fairly short lengths and are diffi- 

 cult to install in firm marine soils. 



The deadweight anchor is usually a concrete block cast at the site. The 

 design anchor weight, W t , is determined by the forces available to cause 

 movement and the degree of resistance produced by the static friction of the 

 bottom conditions (mud, sand, or rock bottom). Based on a static analysis, 

 the relationship between these variables is 



F. F 



(A) 



-ffi 



where 



F = lateral mooring line peakload 



F = factor of safety 



y = coefficient of soil static friction 



Y = unit weight of water 



Y = unit weight of concrete in air 



Anchor piles are designed by finding the ultimate lateral resistance of 

 the pile-soil system and increasing the lateral mooring load, F t , by a fac- 

 tor of safety, F , to determine the design lateral load on the pile. The 

 ultimate lateral resistance of the anchor pile is reached when either the 

 passive strength of the surrounding soil is exceeded or when the yielding 



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