(1) Preliminary Cross Section (modified from Figure 7-116) 



CREST ELEVATION VARIES 



Wr _ M/„ 



%/!^w^WM^)\y^'>jm^kk/'^-' V V ^K^ ^ ^mymi 



10 15 



BOTTOM ELEVATION -IZOm' 



Wa = WEIGHT OF INDIVIDUAL ARMOR UNIT 

 Wr = WEIGHT OF PRIMARY COVER LAYER IF MADE OF ROCK 

 r^ = COVER LAYER THICKNESS 

 rj = THICKNESS OF FIRST UNDERLAYER 

 e = ANGLE OF STRUCTURE FACE RELATIVE TO HORIZONTAL 



(2) Crest Elevation. Established by maximum runup. Runup (R) 



estimate: 



Hg = 6m 



d = 16.5 m 



T = ? (use point on runup curve giving maximum runup) 



16.5 



H 



= 2.75 (use Fig. 7-20) 



cot e 



R/H'l 

 o ^max 



R (m) 



Crest Elevation 



1 



1.5 

 2.0 

 2.5 

 3.0 



1.05 

 1.10 

 1.05 

 1.00 



6.3 

 6.6 

 6.3 

 6.0 



use 10.8 



use 11.1 



use 10.8 



use 10.5 



Waves over 6 m will result in some overtopping, 



8-48 



