Table 4. Equation 14 predicts the statistical mean trend of the experimental 

 data. Since this is the most probable damage level for a given H/Hj ratio 

 based on the empirical evidence available, it is appropriate for application 

 in estimates of expected damage. Designers should be sure also to consider 

 the damage predicted by the upper 95 percent confidence limit of the pertinent 

 model test (as shown in Table 4) and report these predictions in their docu- 

 mentation of the design analysis. 



Table 4 



Damage Level Predictions at Selected Design Wave Exceedances 



in Percent Displacement of the Armor Layer* 



H 

 "d 



Quarrystone 

 (Nonbreaking) 



Quarrystone 

 (Breaking) 



Quadripods 

 (Nonbreaking) 



Tribars 

 (Nonbreaking) 



Dolosse 

 (Nonbreaking) 



Dolosse 

 (Breaking) 



1.00 



3.0/24.7 



2.0/10.2 



3.0/18.6 



3.0/10.4 



2.0/4.3 



2.0/7.4 



1.05 



4.2/25.7 



2.4/10.6 



4.0/19.5 



3.8/11.1 



2.2/4.5 



2.4/7.8 



1.10 



6.0/27.2 



2.9/11.0 



5.5/20.7 



4.9/12.1 



2.4/4.6 



2.9/8.2 



1.15 



8.5/29.6 



3.5/11.6 



7.4/22.6 



6.2/13.4 



2.6/4.9 



3.4/8.7 



1.20 



12.1/33.1 



4.1/12.2 



10.0/25.1 



7.9/15.1 



2.8/5.1 



4.1/9.4 



1.25 



17.1/38.2 



5.0/13.0 



13.4/28.6 



10.1/17.3 



3.0/5.3 



4.9/10.1 



1.30 



24.2/45.5 



6.0/14.0 



18.1/33.3 



12.9/20.1 



3.3/5.6 



5.8/11.1 



1.35 



34.2/55.8 



7.2/15.2 



24.5/39.8 



16.5/23.7 



3.6/5.9 



6.9/12.2 



1.40 



48.4/70.4 



8.6/16.7 



33.0/48.5 



21.0/28.4 



3.9/6.3 



8.3/13.6 



* Displacement of more than 30-40 percent of the armor layer will often involve erosion 

 of underlayers, which in practice requires a repair effort of greater scope than re- 

 placement in kind. 



62. Tables 3 and 4 include predictions for only four types of armor 

 units, two of which do not include breaking wave conditions. This is unfortu- 

 nate, but it leaves the designer with no option but to apply subjective Judg- 

 ment to choose damage coefficients which are close to those of the most simi- 

 larly shaped armor unit in the same wave conditions. Slender concrete armor 

 units, including nearly all concrete types more complex than plain cubes, are 

 subject to breakage in place from impacts between individual units in the 

 armor slope. This breakage would presumably be accompanied by displacement of 

 the broken pieces during an extreme storm. An increase in S of 50-100 per- 

 cent would provide some allowance for this likelihood, but there are no data 

 currently available with which to more precisely predict breakage or its 



40 



