h - H - lj..6 " 13 = Soil, below still water level. 







Accordingly, to obstruct the oscillating wave completely, the breakwater 

 should, rise to not less than 17o6 feet above still water level. 



39ij.. With d = 32 feet_, R and M may be found by 



(d + H + h^) M + P^) wd^ , ^^^^ 



\ = 2 " "2- 



(d . h^ -. H)^ (x^ * P^) _ ^3 , 



M = 



e 



R 

 e 



(32 + 17.6)fe2.5 (32) ■«• li90] _ 62.5 (32) 

 2 2 



R = 28,750 pounds. 



M = (li9.6)^ C62.5 (32) -^ 1i9Q) „ 62.5 (32)^ 

 e S"^ S ' 



M = 6795,630 foot-pounds 

 e • ' 



395 o The width of the concrete structure is found by setting up tbs 

 x^eight of the breala-rater in terms of the unknovm width, x, using submerged 

 weights below still water level. If l50 pounds per cubic foot is the 

 weight of the concrete in air and(l50 - 62,5)= 87.5 pounds per cubic foot 

 the weight of concrete in water, the equation is 



weight = 18X (150) ^- 32X (150 - 62.5) = 5500X (ll;5) 



If, for stability, it is required that the resultant of wave pressure and 

 weight must fall within the middle third of the base, then 



906.5X'^ - 163 c3X^ = 685,700 



X - 30 feet, 

 and the weight = 5500Z " 165;, 000 pounds 



192 



