















P=0.1 







P = 0.4 





















/^M0^ 



/<53^\ 



D n50 A/D n50 F=4.5 /^ 



D n50 A/D n50 F=2 



^> 





D n 50 F/D n 50 C = 4 



(a) 



(b) 





P=0.5 







P = 0.6 





^s' No Filter 



















P^CJ-CyT\ No Core 



/0s 



D n50 A/D n 50 C = 3.2 







(0 



(d) 





D n 5Q A = Nominal Diameter Armor 







D n 5Q F = Nominal Diameter Filter 







D n 5Q C = Nominol Diameter Core 







Structures on Fig. 5a, 5c, and 5d 



Have Been Tested 





The Value of P for Fig. 5b Has Been Assumed 



Figure 47. Permeability coefficient P (Van der Meer 1987) 



of breakwater armor layers; however, each has limitations and assumptions 

 which need to be considered in design. 



Statically stable low-crested breakwaters 



Low-crested breakwaters are similar to conventional non-overtopped 

 structures, but are more stable due to the fact that a large part of the wave 

 energy can pass over the breakwater. The increase in stability can be 

 physically explained by the different wave motion which acts on the 

 structure's slope. For non-overtopped structures, the majority of runup water 

 will return during the down-rush (except for the part that penetrates the core). 



Chapter 4 Structural Design Guidance 



83 



