the procedure is as follows: 



(a) The friction angle, 4', and unit weight, Y, , in the vicinity of 

 the anchor fluke should_be estimated (this may difficult) . 



(b) The parameter N is obtained from Figure 4, given <p and D/B. 



(c) The short-term Molding capacity, F , is obtained from Equation 6. 



Soil data unavailable. If strength data are unavailable, then the 



o 



use of a friction angle of 30 and a unit weight of 60 pcf is recommended. 



Design curves using these parameters are presented in Figure 10. The 



short-term static holding capacity, F , may be taken directly from the 



curves given L, B, and D. Linear interpolation between the curves may 



be used for values of B not presented. 



Field test . The measured holding capacity from a field test can be 

 considered to represent the proper short-term holding capacity, because 

 suction will not be significant in cohesionless soil. 



7. Determine Type of Loading . The type of loading should be 

 determined in a manner identical to that of Step 4 for cohesive soils. 



If the loading is short or long-term static, the estimated design holding 

 capacity is F as calculated in Step 6c, 6d, or as measured in a field 

 test. 



8. Determine Grain Size . If the loading type is long term repeated, 

 a grain size analysis of a disturbed sample should be performed. If 



the median grain size is found to lie between .02 and .2 mm, either a 

 different mooring system design should be developed (i.e., one which 

 reduces effects of repeated loading) or high factors of safety (greater 

 than 10) should be used. 



9. Determine Anchor Relative Embedment Depth . For other grain 

 sizes, it is necessary to determine whether the anchor is to be considered 

 "deep" or "shallow". This may be done by referring to either Figures 4 



or 10, and determining whether the particular range of design parameters 

 places D/B below or above the sharp breaks in the curves. 



(a) If the anchor is "shallow" the design repeated load holding 

 capacity is one-half F from 6c or 6d. 



(b) If the anchor is "deep", it is necessary to calculate the short- 

 term holding at the D/B at which "shallow" behavior changes to "deep". 

 This D/B corresponds to the break points in the curves of Figures 4 and 

 10. The same values of B, L, $, and Y, as used previously should be used 

 and Step 6 should be repeated with the new D/B. One-half of the short- 

 term holding capacity calculated using these parameters should be used 

 for design purposes. 



15 



