where A and B are empirical coefficients yielding runup trends very simi- 

 lar to those proposed by Ahrens and McCartney (1975). Their regression showed 

 similar trends and correlation, as indicated in Table 6 and Figure 13. 



Table 6 

 Runup Coefficients of Losada and Gimenez-Curto (1980) 



Armor Unit 



Riprap 



Quarrystone 



Quarrystone 



Tetrapods 



Dolosse 



Quadripods 



A 



1.789 

 1.451 

 1.370 

 0.934 

 1.216 

 1.538 



-0.455 

 -0.523 

 -0.596 

 -0.750 

 -0.568 

 -0.248 



Correlation 

 Coefficient 



0.96 



0.81 



0.61 



0.74 



0.74 



0.86 



DC\I 



RELATIVE RUNUP 

 R/H = A [1 -eB?] 

 | = tane/Al H/L 



RIP-RAP^ 



12 3 4 5 6 



SURF SIMILARITY PARAMETER, ^ 



Figure 13. Relative runup versus the surf parameter 

 (after Losada and Gimenez-Curto 1980) 



75. Irregular runup can be predicted, based on either of the above re- 

 lations, by applying a Joint cpd for the sea state (Longuet-Higgins 1975 and 

 Ochi 1980) to predict the runup of each wave as a function of its steepness 

 H/L . This process applies the principle of equivalence, first proposed by 

 Saville (1962), which assumes that the effects of each wave in an irregular 



50 



