54 
CONCRETE SILOS 
Foundations 
The site of the silo having been selected and its size determined, the 
excavation should be laid out. This may be done conveniently with a 
sweep similar to the one shown on this page. A heavy stake 
Laying Out jg driven in the center of the place selected for the silo and allowed 
the Work project above the surface about 1 foot. The arm of the sweep 
may be made of a two-by-four at least 2 feet longer than one-half the 
inside diameter of the silo. The arm swings about the stake as a center, 
being held to the latter by a large spike. A chisel-shaped board or tem- 
plate is placed as shown on the arm of the sweep, so that when the latter 
is swung around the stake, the chisel-shaped board will describe a circle 
with a diameter feet greater than the inside diameter of the pro- 
posed silo. This will give the outer line of the excavation and also 
foundation. 
Simple sweep, convenient in laying out excavation. 
The excavation should be carried to a depth not to exceed 6 feet below 
the floor of the barn where the silage is to be fed. The objection to going 
deeper is that it adds to the labor in removing the silage. In 
Excavating cases, however, the foundation should be established below 
frost. All of the earth within the line described by the sweep should be 
removed down to a point one foot from the bottom, and below this the 
excavation should be made the shape and size of the foundation, 2 feet 
wide by 1 foot in depth, so placed that the outer edge will come directly 
up to the edge of the excavation, assuming that the sides of the latter are 
perpendicular. 
If the silo is to be equipped with a concrete chute, the foundation for 
the chute should be put in at the same time as that for the silo. As the 
chute is rectangular in shape, no difficulty should be encountered in 
excavating for the foundation, which will be at the same depth as the 
silo foundation, and 2 feet in width by 1 foot in depth. 
The concrete for the foundations should be made in the proportion 
of one sack Portland cement to 3 cubic feet of coarse sand, to 5 cubic 
feet of screened gravel or crushed stone. The sand should be 
Placing the f ^^^^ qj. organic matter, and the gravel or stone should 
Concrete contain no particle smaller in size than 3^ inch. The materials 
