SOLUTION: An estimate of the reflection coefficient can be obtained froii 



Figure 2 or 3. Calculate 



1 6 



= 0.30 



2d 2(10) 

 From Figure 2, with H^/2d = 0.3 and a = 30°, read Hj^g/2d = 0.47. Therefore, 



\s " 0.47(2d) = 9.4 feet (2.87 meters) 



Alternatively, from Figure 3 for a = 30°, li,^/^-; = 1-61 or 



\s " 1-6U6) = 9.7 feet (2.96 meters) 



This estimated Mach-stem wave height is subject to limitations imposed by 

 the maximum breaker height that can exist in the given water depth. This 

 breaking wave height is given approximately by H./d = 0.78 or, for the 

 example 



\ = 0.78d = 0.78(10) = 7.8 feet (2.38 meters) 



The wave at the structure is thus limited to a height of 7.8 feet. The 

 remainder of the calculations are based on this maximum wave height. 



The maximum wave force (crest at the wall) can be estimated using SPM 

 Figure 7-70 by assuming that the maximum wave height of 7.8 feet is the sum 

 of an incident wave and a reflected wave, each 3.9 feet (1.19 meters) 

 high. Calculating 



"i 3.9 



and 



3.9 

 '-J = K = 0.00189 



gT (32.2)(8)- 



From SPM Figure 7-70, read from the top part of the figure, 



F 



wd 



and from the bottom part of the figure, 



F 



-^ = 0.38 



wd 



II 



