PRESSURES IN STEEL GRAIN BINS. 



n.itural or hyperbolic logarithms. A brief table of hyperbolic logarithms is given in Table IV. 

 To find the hyperbolic logarithm of any number, using a table of Brigg's or common logarithms, 

 use tht- rrlat ion: The hyperbolic or Naperian logarithm of any number common or Brigg's 

 logarithm X 2.30259. 



The author has calculated the lateral pressures on steel plate bins, Fig. 2. 



Ca/cufafec/ 



Pressures 

 Wheat 50 lbs.cu.ft. 

 //* fan 4*0.552 



' 3 45 67 

 Pressure in Ibs.per sq. in. 



FIG. 2. LATERAL PRESSURE IN STEEL PLATE GRAIN BINS CALCULATED BY JANSSEN'S 



FORMULA. 



To use Fig. 2 to calculate the pressures in rectangular bins, calculate the pressure in a circular 

 or square bin which has the same hydraulic radius, R (R = area of bin * perimeter of bin), as 

 the rectangular bin. 



It will be seen in Fig. 2 that the pressure varies as the diameters, where the height divided 

 by the diameter is a constant. By using this principle the pressure for any other diameter within 

 the limits of the diagram may be directly interpolated. 



Problem I. Required the lateral pressure at the bottom of a cement lined bin, 10 ft. in 

 diameter and 20 ft. high, containing wheat weighing 50 Ib. per cu. ft. Assume /*' = 0.416, and 

 k = 0.6, also R will = 2\ ft., w = 50 Ib., h = 20 ft., and Jfe-/ = 0.25. 



Now from (8) 



5Q X 2.5 

 0.416 



300(1 - < 



(j _ g-0.26 x M/2.8) 



Now from Table IV the number whose hyperbolic logarithm is 2.00 is 7.40, and 



L = 300 ( I ) , 



V 7-40 9 



= 260 Ib. per sq. ft., 

 = 1.8 Ib. per sq. in. 



