where d =2.3 is the depth at the toe of the wall when the SWL 

 is at MHHW. The hydrostatic force and moment are given by 

 Equations 7-90 and 7-91, 



^i^^i + M^ 64(2.3 + 7.02)2 „ ,^ 



R = — ^ = ^^ = 2,780 Ibs./ft., 



'2 2 



(d^ + h) 2.3 + 7.02 „ ,^^ Ib.-ft. 



M, = R, ^ = 2,780 = 8,640 -^- . 



^ * 3 3 ft; 



The total torce and moment are therefore, 



R^ = R^ + R^ = 2,200 + 2,780 = 4,980 Ibs./ft. , 



Ib.-ft. 



M, = M + M = 12,900 + 8,640 = 21,540 -7— • 

 t m s jj_ 



(b) When the SWL is at MLLW, the structure is landward of the still- 

 water line. The distance from the Stillwater line to the struc- 

 ture X is given by the difference in elevation between the 

 SWL and the structure toe divided by the beach slope, 



X = ^ = 40 ft. 



' 0.05 



The limit of wave runup is approximately, 

 2Hb 2 (9.0) 



0.05 



360 ft. 



The dynamic component of force from Equation 7-97 is, 



^dfeh / X \3 64 (9.9) (7.02) / 40\ „ ^ 



R^ = 1 = — '^ — 1 = 1,560 Ibs./ft., 



2 \ xj 2 \ 360j 



and the moment from Equation 7-98 is. 



hK j ""i^ _ 64 (9.9) (7.02)2 / 4o\4 ^ Ib.-ft. 



M^ = 1 = ' — — 1 = 4,870 ^ 



<-2l 4 \ 360/ ft. 



The hydrostatic force and moment from Equations 7-99 and 7-100 

 are, 



"^K I ^iV 64(7.02)2 / 40 V „ . 



R, = -— 1 = — ^^ 1 = 1,250 Ibs./ft., 



^ 2 \ x^l 2 \ 360/ 



and 



, ^i\' 64(7.02)3 / 40V Ib.-ft. 



M^ = -— 1 = — 5- 1-—- = 2,590 



6 \ xj 6 \ 360/ ' ft. 



7-163 



