Concrete Silos 123 



it strength and stability. The type usually recom- 

 mended for silos is made from 24 gauge metal, has the 

 ribs 4 inches apart and 15/16 inch high, and comes in 

 sheets 24 inches wide and 10 and 12 feet long. For 

 silo work these sheets are curved at the mill to the de- 

 sired radius. These sheets can either extend down into 

 the foundation, as shown in the illustration, or can 

 begin at the top of the foundation. In the latter case 

 dowel pins are set in the foundation, and allowed to 

 extend several inches above it, for attaching the first 

 ring of Hy-Rib. The construction as shown in the illus- 

 tration is recommended, however, carrying the metal 

 down to the footings. 



It will be noted also that rib bars are used to give 

 stability to the walls while being plastered. These are 

 % inch ribs, wired to the metal sheets, and left in as 

 a permanent part of the silo. Plaster is applied on both 

 sides of the metal to a total thickness of 3 or 3% inches. 



In this type of construction the builder may erect 

 the metal to a height of 30 feet before beginning to 

 plaster, or he may erect it in sections and plaster, as 

 desired. After any plastering is done, however, it will 

 require at least a half day to harden before any more 

 metal is placed. 



The roof of a Hy-Rib concrete silo may be of a cone 

 shape, a dome shape, or an octagonal hip, which are all 

 constructed of Hy-Rib covered with 2 inches of con- 

 crete, back-plastered underneath. The chute may be 

 built in connection with the side walls using Hy-Rib of 

 any desired size, thereby making the chute, side walls 

 and roof of silo one complete unit with the foundation. 



A silo similar to the above is made by the use of 

 Trusridge expanded metal, made by the Edwards 

 Metal Structures Company, Kansas City, Mo. In this 



