Vanoni and Raichlen tested various model-to-prototype scales. Scales 

 were 1:40 and 1:45 in the cases discussed above; however, the scales are 

 not appreciably different and observed runup values were comparable be- 

 tween scales. The principal reason for using different scales was the 

 ability to model prototype armor units of varying weight (and stability) 

 with the same model armor unit. 



Results from Vanoni and Raichlen (1966), Jackson (1968a), and Dai 

 and Kamel (1969) for selected armor units are summarized in Table 14. 

 The Vanoni and Raichlen tests were for rather small scales; Jackson, and 

 also Dai and Kamel, had intermediate scales, and Dai and Kamel included 

 tests at a large scale. Quarrystone values are included in the table 

 with Jackson's test results for size comparison with the quarrystone 

 used by Vanoni and Raichlen. 



Dai and Kamel' s tests for quadripods, including tests at the same 

 scale, give r values slightly higher than Jackson's. The difference 

 may be partly attributable to different experimental setups and partly 

 to different relative sizes of the quadripods. 



The tribar tests of Vanoni and Raichlen give r values comparable 

 to those of Jackson. Lower r values would be expected for the former 

 because of lower H'/k values (or larger armor unit size relative to 

 the wave) but the effect (if present) is apparently offset by the higher 

 core of Vanoni and Raichlen's structure- -which would increase runup 

 somewhat by reducing wave transmission—and because Vanoni and Raichlen 

 tested one layer of tribars compared with the two layers tested by 

 Jackson. 



(2) Impermeable Structures . Testing of concrete armor units on 

 impermeable slopes has been rather limited; most testing has involved 

 permeable rubble-mound structures designed for high-energy environments. 

 Only two sets of tests for concrete armor units on impermeable slopes 

 are discussed here, one for runup on tribars and the other for runup on 

 Gobi blocks. 



Vanoni and Raichlen (1966) tested a structure with a 1 on 3 slope 

 : ronted by a horizontal bottom and armored with a combination of tribars 

 and quarrystones. Tribars extended from below SWL to a distance above. 

 SWL, but the distance varied depending on the water depth. Quarrystones 

 extended the rest of the way to the structure crest. 



One set of the experiments was for a relatively low water level, for 

 which all runup was both below the quarrystone level and below the crest 

 of the core. These conditions essentially constitute an impermeable 

 structure. The correction factors (r) given in Table 15 can be com- 

 pared with values in Table 13. Values of H^/k^ in Table 15 are 

 markedly lower than those in Table 13, and the greater roughness is 

 certainly a major reason for the lower correction factors in Table 15. 



