Figure 36 also presents the total lateral load capacity, Ri_, of the 

 deadweight anchor with Z/B = 0.1 on category D soil. For these conditions, 

 the passive wedge resistance, R , comprises about 12 percent of the total 

 lateral load capacity, R.. The^fact that the nassive wedge is a minor 

 contributor to the lateral load capacity is quite fortunate. The passive 

 wedge, in some environments, especially in category D soils, could be sub- 

 stantially removed by scour. Because the wedge is a minor contributor, 

 its contribution to the lateral load capacity can be neglected without 

 drastically affecting the anchor block dimensions. 



Results . The lateral load capacity analysis suggests sizes reouired 

 for deadweight anchors in various soil categories. These are presented 

 in Table 15. The results of this phase are significant when considering 

 potential technicues for contsructing, transporting and installing dead- 

 weight anchors for OTEC. For example, if a deadweight anchor with a 

 lateral load capacity of 18 MN (4x106 lbs) were required at a particular 

 OTEC site with category C sediments (Figure 35), that lateral load caoa- 

 city could be provided by a square-olan deadweight anchor 22 m (72 ft) 

 on a side. This anchor could be transported in the well of the heavy- 

 lift ship Glomar Explorer (well width 22.5 m (74 ft). However, deadweiahts 

 of greater width could not be transported within the shin's well, and 

 other transport techniques would be necessary. 



Lateral Load Canacity as a Function of Cutting Edge Length and Anchor Width 



Assumptions . One possible way of increasing the lateral load canac- 

 ity of an anchor block of given plan dimensions is to increase the length 

 of the cutting edge. Increasing the length and embedment of the cutting 

 edaes moves the base shear plan downward into presumably stronger material 

 and increases the size and load capacity of the nassive wedge. 

 Unfortunately, the lever arm of the overturning moment is also increased, 

 and thus the lateral sliding failure mode may no longer be controlling. 



The review of lateral load canacity as a function of relative cutting 

 edge length, i.e., Z/B ratio, assumes that lateral sliding would be main- 

 tained as the dominant failure mode. This failure mode can be maintained at 

 the exoense of restricting the direction of load aonlication to only one 

 direction, i.e., by restricting the multi-direction anchor to a uni- 

 direction anchor. Reduction in the overturning moment is achieveH by 

 lowering the moorina line attachment noint as illustrated in Fioure 37, or 

 by re-distributina the anchor mass to better counter the overturning 

 moment. The uni-direction anchor is suitable for use in multi-noint moor- 

 ings and in areas of uni-directional loadina (e.g., moorings near the axis 

 of the Gulf Stream) . 



Results. Lateral load canacity predictions for deadweights with Z/B 

 ratios other than 0.1 were calculated using the sane assumptions and tech- 

 niques emnloyed above for deadweiahts with Z/B =0.1. The results are 

 presented in Fiaures 38, 39, and 40 for Soil Categories A, C, and D 

 resnectivelv. 



77 



