•Crest of Clapotis 



Top of Wall 



TTPTTTTTTTTTI 



Yc 



SWL 



Figure 7-96. Pressure distribution on wall of low height. 



Similarly, the reduced moment about point A is given by 



M' = r^M 

 m 



where the moment reduction factor r^ is given by 



/, \2 / 



and 



'm= [y 



m 



3 - 2 - when 0.50 < - < 1.0 



y / y 



when 



- s 1.0 



y 



(7-80) 



V (7-81) 



The relationship between r^ and b/y is also shown in Figure 7-97. 

 Equations (7-78) through (7-81) are valid when either the wave crest or wave 

 trough is at the structure, provided the correct value of y is used. 



*************** EXAMPLE PROBLEM 32 ************** 

 GIVEN ; 



(a) Wall height b = 4.5 m (14.8 ft). 



(b) Incident wave height H^^ = 1.5 m (4.9 ft). 



(c) Depth at structure toe d = 3 m (9.8 ft). 



(d) Wave period T = 6 s (minimum) or 10 s (maximum). 



FIND; The reduced wave force and moment on the given vertical wall. 



7-174 



