GRAIN PRESSURES IN STORAGE BINS. 11 
EXAMPLE 2. 
Required: The area of steel in square inches per foot in height for 
horizontal reinforcing for a cylindrical concrete tank 25 feet in 
diameter and 100 feet in height at four levels, (1) at bottom, (2) at 
height of 25 feet, (3) at height of 50 feet, (4) at height of 75 feet. 
« (fa=18000). 
From Table 2: 
H 
At bottom 5=5e =4; 73 = 0.000818 AS Oallsqe in: 
At 25’ "a= 2 23; = 0.000792  A=0.495 sq. in. 
pn. 30 
At 50’ 0 Di 9523 Je 9.000720 A =0.450 sq. in. 
la OD, 
At 75’ 0" = 52=1; Fo=0.000527 = A= 0.329 sq. in. 
From Plate IJ: As before, follow the vertical line at the right- 
hand side for diameter 25 feet upward to its intersection with the 
oblique line representing 100 feet for the height of the grain. From 
this intersection project horizontally to curve 2 for f,=18000, then 
vertically to the line for diameter 25 feet of the set of radial lines for 
steel. This last intersection will be found to be horizontally opposite 
a point on the scale for steel areas a little above 0.5 or about 0.51 
square inch, which equal: area of steel per foot in height at the 
bottom. 
In the same manner by starting in turn with the intersections of 
the vertical line for 25-foot diameter with the oblique lines for 75 
feet’ height of grain, 50 feet height of grain, 25 feet height of grain, 
the steel areas may be determined for these levels. 
The left-hand section of the plate provides a means of determining 
~~ the spacing of any size bar there listed to give a required area of 
steel per foot in height. 
Any horizontal line through a required steel area will intersect the 
oblique line for any chosen size bar on the vertical line giving its 
required spacing. 
For the present example, by reading on the horizontal line through 
0.51, it will be found that any of the following combinations of bars 
and spacings will give the required area of steel at the bottom of 
the tanks: 
Pee OMMmaSuaifeee 24 So ee se 7” on-center. 
eigen Orde by a, fats ats ...2..-2:__.-.--7’’ on center. 
2’’ by #5’ or 14”’ by 3” or 1” by 2” flats at___-___9’’ on center. 
peecolites gee seme te 2. e297 on-center. 
Payee etsnteee.s 2 10” on center. 
Dae? by ad or pats by pe’! or see by By flats ain Nae ae on center. 
1 Height of grain equals distance from level of reinforcement to top of grain. 
