in Figures 41 and 42. Note tiiat the structure head shown in Figure 41 (outer 

 20 ft along the structure crest) is approximately 3 stone-sized thick with no 

 primary underlayer. 



Stone VolumeA/Veight Estimate 



The total volume of each layer of stone was determined by reference to 

 Figures 40. 41. and 42. The layer volume was then multiplied by the stone unit 

 weight (165 Ib/cu ft) and assuming 37 percent porosity (multiplied by 0.63). The 

 volumes and weight of each layer are given in Table 8. 



Table 8 



Layer Volume and Weight of Total Stone 





Armor 

 (UV'=10to14tons) 



Primary Underlayer 

 (W= 1.0 to 1.4 tons) 



Bedding Layer 

 (W= 6 to 120 lb) 



Volume, cu ft 



71,400 



6,100 



23,600 



Weight, tons 



3,700 



320 



1,200 



There is a need for a tie-in to the existing structure to provide better groin 

 performance and enhance interlocking between the existing groin and the goin 

 extension. Quantities required for the transition sections will be determined from 

 detailed surveys of the existing groin taken during the preparation of construction 

 plans and specifications. 



Chapter 4 Structure Design 



53 



