CHAPTER VII 

 MONOLITHIC CONCRETE SILOS 



In the building of silos in which the concrete walls are 

 moulded or as we generally say, monolithic silos, the common 

 thickness of wall is 6 inches. This is plenty heavy enough 

 for any reasonable size, up to a diameter of 25 feet and a 

 height of 50 to 60 feet. The mixtures used will of course 

 depend very largely upon the grade of gravel or other aggre- 

 gate. Mixtures of 1 to 4 and 1 to -3^ are, however, usually 

 found in the best silos. Stones should never be found in the 

 wall larger than one-third the thickness of the wall. 



Reinforcement. Vertical reinforcement is commonly 

 recommended for concrete silos, but it is of little or no impor- 

 tance, as there has never been a failure due to lack of vertical 

 reinforcement in any masonry silo, except where a very thin 

 wall has " en built or the horizontal steel placed over 3 feet 

 apart. 



The horizontal reinforcements may be determined from 

 the table on page 78. If other sizes of steel are used than 

 those shown in the table it will be a simple matter to 

 determine the equivalent amounts. One 5/g-inch rod is equal 

 to two ^-inch rods, while one J^-inch rod is equal to four ]/- 

 inch rods. 



Forms. In the building of a concrete silo a scaffold may 

 be arranged similar to that described in the building of block 

 silos, but in addition to this equipment, forms will be neces- 

 sary. Several kinds are on the market at present, and 

 usually reliable information may be secured concerning them. 

 The author has not had wide enough experience in their 



