Concrete Silos 



61 



Excavation, Floor and Footing 1 . Earth Wall Can Be Made 

 Vertical Where Ground Is Firm. 



a line of drain tile. This drain will carry off any water 

 which may accumulate in the silo, and which, in some 

 cases, has been known to rise to such a height as to 

 exert a pressure on the silo walls greater than they 

 were designed to resist. If a drain is used, the floor of 

 the silo should have a pitch toward the center of about 

 i/4 inch to 1 foot. The drain should also be covered 

 with wire netting to keep it open, and should be pro- 

 vided with some form of trap so that the air cannot 

 enter from the outside. 



If the foundation walls on the silo are made thicker 

 than the walls of the superstructure, they should line 

 up with each other on the inside rather than the out- 

 side. A few years ago it was thought proper to place 



Correct Method of Alignment Between Wall and Foundation 

 Shown at A. Incorrect Method at B. 



