Dai and Kamel (1969) tested a permeable structure using quadripods 

 in conjunction with scale-effect testing. Tests were limited to a 1 on 

 1.5 slope» Data from other investigators indicate that consistent runup 

 values are difficult to obtain on a 1 on 1.5 slope, particularly on 

 rubble slopes. Dai and Kamel's tests also seem to have considerable 

 variance. Their structure configuration used for testing the quadripods 

 was basically the same as used by Jackson (1968a), and some of the 

 values were identical. The relative core height was approximately 

 h a /d s «l.l. 



After reanalysis of Dai and Kamel's data, comparisons with the 

 smooth-slope curves were made. Averages for each dg/H^ value and 

 scale combination were determined. These values indicate no signifi- 

 cant differences between the quadripods with "smooth" and "rough" sur- 

 faces (terms used by Dai and Kamel) ; also, no significant difference is 

 seen between scales. Individual values of r range from r ss 0.38 to 

 r = 0.70, but the extremes appear to reflect questionable runup values 

 as compared with other data. The overall average for the r values is 

 r as 0.57. Table 12 presents values of r for quadripods on 1 on 1.5 

 slope and for specific dg/H^ values, but each r value is an average 

 of values obtained for one to five wave steepnesses each. 



Table 



12. Values of r for quadripods on 1 on 1.5 slope (after 



Dai and Kamel, 1969). 



4* 





r (avg) 



dg = 0.305 m (1 ft) 



dg = 0.61 m (2 ft) 



dg ■» 4.57 a (15 ft) 



Smooth quadripod 



Quadripod 



Rough quadripod 



4.0 



4.5 



1 



0.57, rough (2 points) 

 0.55, smooth (3 points) 



0.63 (2 points) 





5-0 



3.6 



0.49 (1 point) 



0.55, rough (3 points) 

 0.57, smooth (3 points) 



0.57 (4 points) 



8.0 



2.3 



0.59 (5 points) 



0.61, rough (3 points) 

 0.60, smooth (5 points) 



0.46 (2 points) 



*N 



3 data. 









Vanoni and Raichlen (1966) tested a relatively high core structure 

 with relative core heights of h e /dg « 1.32 and h e /d s « 1„79. In the 

 latter case, runup did not exceed the core height (discussed in Sec. 

 V,2,b). The structure slope was first built with one layer of tribars 

 from below SWL to a point slightly below the core elevation, and then 

 the upper part of the structure was built of quarrystone. The tribar 

 section extended above SWL to a height approximately equal to the maxi- 

 mum wave amplitude at the structure toe. The tribars and quarrystone 

 were underlain by two filter layers. Nonbreaking waves were used; 

 runup was caused by surging waves. 



The slope tested by Vanoni and Raichlen was a 1 on 3 uniform slope; 

 test results for certain conditions are given as values of r in Table 

 13. Runup for d^/H^ > 5.0 was limited to the tribar zone, and extended 

 up into the quarrystone section for 2 < dg/H^ < 5. No noticeable dif- 

 ference in r values is seen which would be attributable to the water 

 passing over different armor unit types; e.g., comparison of r values 

 for dg/H£ = 3.0 and d^/H^ = 5.0. 



89 



