If waves act on both sides of the structure, the maximum net horizontal 

 force will occur when the clapotis crest acts against one side when the 

 trough acts against the other. Hence the maximum horizontal force will 

 be F^ - F^, with F^ and F^ determined for the appropriate wave 

 conditions. Assxoming for the example problem that the wave action is 

 identical on both sides of the wall, 



F„^^ = 1.25 (64) (10)2 _ 29 (64) (10)^ 



^net ^ (1-25-0.29) (64) (10)^ = 6,144 Ibs./ft. 

 say 



^net = ^'100 ^bs./ft. (T = 6 sec.) 



The moment about point A at the bottom of the wall (Fig- 7-64) may 

 be determined from Figure 7-67. The procedures are identical to those 

 given for the dimensionless forces. However, in this case the hori- 

 zontal line, M/wd^ = 0.167 indicates the hydrostatic moment about the 

 toe resulting from still water of depth d. Continuing the example 

 problem, from Figure 7-67, with H^/gT^ = 0,0043 and H^/d = 0.50 



—77 = 0.755 ; — — = 0.80 (T = 6 sec.) 



Therefore, 



lb. -ft 

 M^ = 0.755 (64) (10)3 = 48,300 



ft. 



(T = 6 sec.) 



Ib.-ft. 

 M, = 0.080 (64) (10)3 = 5 120 — -— 

 ^ ft. 



When there is still water of depth d on the leeward side, the maximum 

 moment 



Ket = ^c' 0-167 wd3 . 



Therefore, the resultant moment about A is 



^net " ^-"^^ (64) (10)3 _ Q 167 (54) (lo)^ 



Ib.-ft. 

 ^net = (0.755-0.167) (64) (10)^ = 37,600 -7— (T = 6 sec.) 



The maximum moment when there is wave action on the leeward side of 

 the stnacture will be M^ - M^ with M^^ and M^ evaluated for the 

 appropriate wave conditions. For the example problem, if identical 

 wave conditions prevail on both sides of the structure 



^net " (0.755-0.080) (64) (10)^ = 43,200 — ^ (T = 6 sec.) 



Figures 7-68, 7-69, and 7-70 are used in a similar manner to determine 

 forces and moments on a structure which has a reflection coefficient 

 of X = 0.9. 



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7-138 



