6 BULLETIN 789, U. S. DEPARTMENT OF AGRICULTURE. 
If 4xkxp’=N, not equal to 1, 
V=5x W o) 
N 
D 
Let W 
=D’, then the formula becomes, 
L=kV 
For values of W other than 50 pounds V and LZ may be determined 
by direct proportion. (See Example 4, page 14.) 
HORIZONTAL REINFORCING FOR CYLINDRICAL CONCRETE BINS. 
In a cylindrical tank the total pressure on any diameter for 1 foot 
in height is equal to the lateral pressure per square foot at that level 
times the diameter in feet, or LX D. This pressure, tending to burst 
the tank, produces tension in the walls, and, since two cross sections 
of the wall are cut by each diameter, the total tensile stress on each 
L : Ds Re. 
suming that all of the tensile stress is taken by the steel reinforcing, 
and indicating the allowable unit stress in the steel by f,, the cross- 
sectional area of steel required in square inches per foot in height at 
that level is given by the formula: 3 
cross section of the wall for 1 foot in height is equal to 
EXD 
RPE Deeg 
This formula may be written, 
Lee 1 
PD OE 
Since the pressure factor z is determined by 7 we can tabulate 
values for the steel factors pator different values of - (See Table 2.) 
