162 X 2.92 = 470 psf. 

 The area of the residual passive pressure triangle is: 



470 X 2.92 X 2" = 690 pounds per lineal foot of wall; 



the tie rod reaction then becomes: 



2,290 - 690 = 1,600 pounds per foot of wall. 



d. Design Step : Bending Moment in Sheet Piling . Maximum moment 

 occurs at elevation of zero shear. Let "Z" = distance below MLW to plane 

 of zero shear. Then in the case of Figure 5 Z is found as follows: 



Shear at MLW = 1,600 - 540 - 200 = 840 pounds 

 2 



Z^ 

 262Z + IStj- = 840 pounds where Z = 2.92 feet 



Z2 

 262X = 763 18j- = 77 



|- = 1.46 I = 0.97 



Moments of forces above plane of zero shear taken with respect to 

 plane of zero shear are shown in the following tabulation: 



Force Arm Moment 







Clockwise 



Counterclockwise 



1,600 



4.92 



7,870 





540 



5.92 





3,200 



220 



3.39 





750 



763 



1.46 





1,110 



77 



0.97 





75 



1,600 5,135 



Bending moment in sheet piling per foot of wall length = 7,870 - 5,135 

 = 2,735 foot-pounds. 



This is conventionally called the "free earth support" moment. 



The free earth support moment may be reduced by a factor of 30 per- 

 cent to allow for beneficial effects related to flexibility of sheet 

 piling (Terzaghi, 1954). 



Hence, design bending moment = 0.7 x 2,735 = 1,910 pounds per foot. 



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