significant wave height corresponding to 0- to 5-percent damage, gener- 

 ally referred to as no-damage condition. Kjj is the stability coeffi- 

 cient for the respective armor unit and damage condition. 



Table 7-7. h^£)=Q and K^ as a Function of Cover-Layer Damage and Type of Armor Unit 



Breakwater Trunk, n = 2, Random Placed Armor Units, Nonbreaking Waves, and Minor Overtopping Conditions. 



The percent damage is based on the volume of armor units displaced 

 from the zone of active armor unit removal for a specific significant 

 wave height. This zone, as defined by Jackson (1968 a), extends from 

 the middle of the breakwater crest down the seaward face to a depth 

 equivalent to one zero-damage wave height ^d=o below the Stillwater 

 level. Once damage occurred, testing was continued for the specified 

 wave condition until slope equilibrium was established or armor unit 

 displacement ceased. 



The following example illustrates the ways in which Table 7-7 may 

 be used. 



************** 



EXAMPLE PROBLEM *************** 



GIVEN ; Rough two-layer quarrystone breakwater designed for nonbreaking 

 wave and minor overtopping from a no-damage design wave of H^..^ = 8 

 feet and a K^; = 4.0. 



FIND: 



(a) Anticipated percent damage from a wave height H = 9 feet, 



(b) anticipated percent damage from using a value of K = 8.2 in the 

 stability analysis instead of K = 4.0, and 



(c) appropriate values of wave height, H and stability coefficient, 

 K for acceptable 30- to 40-percent damage. 



7-178 



