to the design wave height for both blocky quarrystone and rounded boulders. 

 Also compute the overlay weight per meter of revetment length based on the 

 selected maximum runup. 



SOLUTION ; To compute the zero-damage median weight, use Table 3 to calculate 

 the local significant wave height at the toe of the structure. To use Table 

 3, compute 



5° - -Js = LI? = 039 



L (gT 2 /2iT) 9.8(5.0) 2 /6.28 



£s _ 1.83 

 H 1.52 



= 1.20 



and the offshore slope = 1 on 100. 



Use Table 3 for H^/L = 0.040, since interpolation Hq/L would not 

 change values of H s /H or H^ax/H^ appreciably, and then interpolate on 

 d s /H^ to get 



H s 



77T = 0.71 (to be used to calculate H„) 



Ho & 



and 



— - — = 1.25 (to be used for runup calculations) 

 H s 



The local significant height is 



H s = 0.71(H£) = 0.71(1.52) = 1.08 meters (3. 54 feet) 



The considerable reduction in the significant height from the deepwater value 

 is due to breaking of the larger and steeper waves over the shallower parts 

 of the 1 on 100 offshore slope. Solving equation (5), using cot 9 = 1.5, 

 gives 



N sz = 1.45(1.5) 1/6 = 1.55 



and using this value in equation (4) with H s = 1.08 meters gives 



1.08 



/ w 50 y/3 



V2.644/ 



= 0.424 



n 55) / 2,644 _ \ 



*• ; ^l.ooo 7 



and W5Q = 202 kilograms (445 pounds) . 



The minimum armor layer thickness for this stone size is computed using 

 equation (2) 



rmin = 2.0 (y^) 1 ' ' 3 = 0.85 meter (2.79 feet) 



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