Ns 3 VS d1/ds 



ALL TESTS [INCLUDING SPECTRAL TESTS] 



LEGEND 



MONOCHROMATIC TESTS 



H[J= MEASURED MAXIMUM BREAKING WAVE HEIGHT 

 SPECTRAL TESTS 



Hd= MEASURED Hmo 



Hd= THEORETICAL MAXIMUM Hmo 



L J tn 

 □ H 



B ¥ 



% 



D D □ 



□ B D 



RELATIVE BERM DEPTH, d1/ds 



Figure 17. Stability number cubed versus relative berm depth 

 for all toe berm stone tests including spectral wave tests 



general spectral design guidance can be developed. The data show that if 

 shallow-water spectral H^ values were used in Equation 2 in conjunction 

 with stability numbers associated with breaking wave height (Figure 14) , the 

 toe berm armor stone would likely be undersized. Thus, once spectral design 

 conditions are known, an estimate of the maximum breaking wave height asso- 

 ciated with the spectrum must be used in sizing the toe berm stone. 



Buttressing Stone Tests 



31. Results of the four stability tests of tribar overlays with toe 

 buttressing stone are presented in Table 2. For the limited tests conducted, 

 the stability of the toe buttressing stones seemed to be independent of 

 d s /L s , d 1 /d s , and H D /d s . Average stability numbers for the tribars and 

 toe buttressing stones were 2.2 and 1.6, respectively, confirming the US Army 

 Engineer Division, Pacific Ocean, design decision that toe buttressing stones 

 need to be approximately 1.3 times the weight of tribar needed for stability 

 in a breaking wave environment. 



29 



