10 BULLETIN 789, U. S. DEPAETMENT OF AGRICULTUKE. 



DETERMINATION OF VERTICAL AND LATERAL PRESSURES IN GRAIN 

 BINS WITH HORIZONTAL REINFORCING FOR CYLINDRICAL CON- 

 CRETE TANKS BY MEANS OF PLATE H. 



By means of the four curves on the chart in Plate II, which have 

 been plotted from values given by Tables 1 and 2, the vertical and 

 lateral unit pressures may be determined for any bin, and in the 

 case of cylindrical concrete tanks the size and spacing of the hori- 

 zontal reinforcing may be obtained without the need of any calcu- 

 lations. 



The manner in which this chart may be used can best be explained 

 by means of several examples, which will be first solved mathe- 

 matically, using the values given by Tables 1 and 2, and then directly 

 from the chart. 



EXAMPLES SHOWING USE OF PLATE II. 



EXAMPLE 1. 



Requiredi: The vertical and lateral unit pressures at the bottom in 

 a round or square bin 15 feet in diameter and 75 feet in height. 



E_n_ 



77 



From Table 1: For -^=5 



V 



■^ = 49.66 and F= 15 X 49.66 = 745 pounds per square foot. 



L 



■^ = 29.79 and -L = 15 X 29.79 = 447 pounds per square foot. 



From Plate II: FoUow the vertical line at the right-hand side for 

 diameter 15 feet upward to its intersection with the oblique line 

 representing 75 feet for the height of the grain. This wiU be found 

 to be on the heavy horizontal line fourth from the bottom of the 

 page. Follow this horizontal line to the left to its intersection with 

 curve 1. Project from this intersection vertically to the line for 

 diameter 15 feet of the set of radial lines for pressures. This last 

 intersection will be found to be horizontally opposite a point on the 

 scale for pressures a little above the line for 750 or about 745 pounds 

 per square foot, which equals the unit vertical pressure. Returning 

 to the fourth heavy line from the bottom, continue to the left to its 

 intersection with cm-ve 4, again project vertically to radial line 15 

 for pressures, then horizontally to the right to a little above the line 

 for 450 or about 445 pounds per square foot, which equals the unit 

 lateral pressure. 



