UNITED STATES DEPARTMENT OF AGRICULTURE 
/ BULLETIN No. 789 ¥ 
Contribution from the Bureau of Markets, 
GEORGE LIVINGSTON, Acting Chief. 
Washington, D. C. PROFESSIONAL PAPER October 6, 1919 
NOTES ON GRAIN PRESSURES IN STORAGE BINS. 
By W. J. Larkin, Jr., Consultant in Bulk Grain Handling. 
CONTENTS. 
Page. Page. 
Infroductiony so <2-hsce2. Sl Sb ese. ce ee 1 | Horizontal reinforcing for straight walls of 
Janssen’siformula:ss 22. eee ese. es 1 Concrete Dimse ioe ie ee So eee 7 
Pressure factors for wheat in round or other Determination of vertical and lateral pres- 
regular concrete bins. .....-..------------- 2 sures in grain bins with horizontal re‘nforc- 
Explanation of PlateI...................... 3 ing for cylindrical concrete tanks by means 
Determination of unit pressures in rectangular OWPla Ge Pigs eek eid eee Sas yee gees 10 
onotherirreswlar binsey.. 4.5.22 52.255- 2 2 Dee TACT TO CTI Cx ah or weit Ce ie sy eee 14 
Determination of unit pressures for various Selected list of publications on the pressure of 
grains in bins of different materials ....... 5 SLORCG! Praline ae Ce ace 15 
Horizontal reinforcing for cylindrical con- 
Grete binses pes eee weed oe ce se hee oe 6 
INTRODUCTION. 
The formula derived by Janssen for the determination of the 
vertical and lateral pressures of grain in bins is one commonly used 
by grain elevator engineers. Most engineers, in their calculations, 
have also made use of a table of values similar to the one here given, 
by means of which the unit pressures are more quickly and easily 
determined (see Table 1). In this bulletin are given rules for the 
more advantageous application of this table, together with addi- 
tional tables and graphical charts which should further facilitate the 
designing of grain bins. 
JANSSEN’S FORMULA.' 
In Janssen’s formula the following nomenclature is used: 
A =area of bin in square feet. : 
P=perimeter of bin in feet. 
fi =hydraulic radius of bin= = 
Notr.—This bulletin is of interest to engineers, particularly those having occasion to design grain storage 
bins. 
1 For the derivation of Janssen’s formula together with descriptions and results of different experiments 
to determine values for the coefficient of friction of grain on bin walls and the ratio of the lateral to the 
vertical pressure at any point, see Ketchum, Milo S., The design of walls, bins, and grain elevators, 2d ed., 
_New York, 1911. 
- 108882°—19 
