T =. I^.^ = 3[;50 pounds per foot of wall 



Sq = h9hB =■ T = II495 pounds per foot of wall 



Z^ = 1.8 feet 



3^2. Substituting these iralues in the expression for the niaxiraimi moments, 

 the maximum positive moment is found to be 



M„ = ^355 foot--DOunds per foot of wall 



and the maximum, negative moment is found to be 



M^ ^ 3680 foot-pounds per foot of wall 

 "2 



3^3 o By decreasing the value of T (that is, making E„ negative), these 

 moments may be equated. Through trial and error the con-ect values of T, 

 M_, Sp, and Z-. are found to be approximately 



T = 33^0 pounds per foot of wall 

 Mq = 1000 foot-pounds per foot of >7all 



Sp = 1?95 pounds per foot of wall 



Z-^ - 2.05 feet. 



The bending moments M^ - M„ ■= 5100 foot pounds per foot run of vra.ll. 

 "1 ^2 



35i|. For stability^ the forces below G must eqjial S„, aid the moments 

 below G must equal Mp„ It has been shown that the pressure p-^. for minimum 

 pile length m.ust be as great as can be generated by the earth at that point. 

 Now the maximujn passive pressure at the depth of p, p, is that due to a 

 •^surcharge" consisting of all the earth above point G, applied to an undisturbed 

 ground mass of height h^. This surcharge load is given by 



¥, 

 \ - ^., (\ * h^). ^ (125) 



where ¥1 ~ 1275 pounds -oer square foot = the surcharge load of the earth above 

 h, ^ 



'h 



■%- 



w^ - w^ = 



hr 



3 feet 



h^. 



2.36 feet 



pounds per cubic foot = the icmit weight of the 

 submerged ground 



172 



