48 
The Coeorado Experiment Station. 
BUILDING MATERIALS. 
The following table shows the quantity of cement, rocks and 
reinforcing required for the foundation and main wall of silos of 
different dimensions. When the sand and rock are obtained togeth¬ 
er in gravel form, the quantity will slightly exceed the number of 
cubic yards of rock designated. Theoretically the sand should just 
fill the voids between the rock particles without increasing the bulk, 
but it is well to add one-sixth to the cubic yards of rock when sand 
and gravel are obtained together. 
BUILDING MATERIAL REQUIRED. 
Dimensions Thickness Cubic yards 
of silo 
of wall 
Tons capac¬ 
in wall and 
Sacks 
Cu. yds. 
Cu. yds. 
♦Rods 
in feet 
in inches 
ity 
foundation 
cement 
rock 
Sand 
Reinforcing 
10x25 
5 
36 ■ 
14.1 
70 
13 
8 
19 
10x28 
5 
42 
15.6 
75 
14 
9 
20.4 
12x28 
5 
61 
18.6 
90 
16 
10 
25 
12x32 
5 
74 
20.4 
100 
18 
11 
26.5 
14x32 
6 
100 
28.7 
136 
26 
16 
32 
14x34 
6 
109 
30.4 
145 
27 
17 
30 
15x34 
6 
126 
32.5 
156 
29 
18 
40 
16x34 
6 
143 
35.5 
166 
32 
20 
43 
16x40 
6 
180 
38.4 
195 
36 
23 
45.5 
18x36 
6 
196 
42.0 
200 
37 
23 
58 
18x40 
6 
229 
46.3 
217 
41 
25 
65 
20x40 
6 
281 
51.2 
240 
45 
28 
72 
* Reinforcing doubled in lower two courses of 15x34-foot silo; in lower three 
courses of 16x34 and 18x36-foot silos ; in lower four courses of 16x40 and 18x40-ft. silos. 
Sheet Iron Forms .—Building forms are constructed of eigh¬ 
teen or twenty gauge black sheet iron, thirty-six inches wide. Each 
set of forms consists of an inside and an outside band. The inside 
band is made up of four sections of equal length. The iron is kept 
in stock in 8-foot lengths and special request should be made to 
have it made up into the required length at the factory. This ap¬ 
plies particularly to the four pieces for the inside form. The out¬ 
side band is either riveted or bolted together with stove-bolts into 
one long sheet. This may be done easily on the farm and hence for 
the outside band the 8-foot sheets may be ordered, with a short 
extra piece when required to make up the total length. The cutting 
with ordinary farm equipment is difficult, however, and for this 
reason inside pieces should be made up at the factory. 
One set of forms can be used in building several silos and the 
farmer should ascertain by correspondence with this college (see 
preface) whether or not there are available forms in his commun¬ 
ity before he himself builds. 
The following chart shows the lineal feet of sheet iron needed 
for both inside and outside forms for silos of different diameter. 
