60 
CONCRETE SILOS 
boards vertically on the outer edge of the ribs, the latter being placed two 
feet apart center to center. This will bring the center of the lower rib 6 
inches from the bottom of the form and the center of the other rib 6 inches 
from the top of the form. The floor boards should be securely nailed to 
the ribs. The surface will then be covered with galvanized sheet metal. 
Each of the eight segments may be made up in a similar manner and when 
bolted together, and if accurately made, they will form a true circle. 
At two points in the circle the ribs and cleats should be cut to permit 
inserting wedges. The flooring boards must also be beveled to fit wedges 
2x4 inches at the top, tapering to 2x3 inches at the bottom, as on page 59. 
After the segments of the form are bolted together, the wedges should be 
driven down. In removing the form, the wedges are first withdrawn and 
the segments then unbolted and loosened as much as necessary to make 
removal easy. 
The inner form is provided with a very simple arrangement for sup- 
porting and also for raising and lowering. Through the 4x43^-inch holes 
centrally located in each rib, a 4x4-inch upright, made of two 2x4 inch 
nailed together, passes. One-half inch holes are drilled in these uprights 
at intervals of feet, corresponding holes on all of the uprights being at 
the same level. The form is raised 2^/2 feet each day. After raising to a 
new position the bolts are inserted in the holes directly under the bottom 
ribs of the form. As the work progresses upward, additional 2x4 's are 
spliced on alternately. 
The outside is made of heavy (No. 18 or 20 gauge) galvanized sheet 
steel, 3 feet in width. The form is made in two or more pieces, strips of 
heavy band iron being 
riveted to the ends of 
each piece, the ends be- 
ing turned out at right 
angles and provided 
with holes to receive 
the bolts by which ad- 
joining sections of the 
form are drawn to- 
gether. One-half inch 
threaded bolts 12 
inches long are used. 
These strips are clearly 
shown, although some- 
what exaggerated, in 
the illustration on page 
56, A heavy iron 
handle is put on the 
outside form opposite 
each pair of 2x4-inch 
uprights to facilitate 
raising. This can be 
done with a simple 
derrick arrangement 
Third stage in the use of University of Wisconsin silo forms, sliow- attached tO the Up- 
ing method of building scaffolding, hoisting material and other irrVita 
essential details. rigntS. 
