DATA FOR DESIGN OF BINS. 



311 



, for a bin level full 



(26) 



: ' w Vl + ol 



The length of the curve of a suspension bunker is given in Table VIII. 



TABLE VIII. 

 LENGTH OF ONE-HALF CURVE, L. 



The curve may be constructed graphically as follows: In (c) Fig. n it is required to pass 

 the curve through the points A and B. The loads I, 2, 3, 4, etc., are laid off in the force polygon 

 (d), and a pole is taken. The equilibrium polygon A-B' is then constructed in (c). Now we 

 know from graphic statics that if two poles be taken for the force polygon in (d), and corresponding 

 equilibrium polygons be drawn through A, the strings meeting on the same load will intersect on a 

 line through A parallel to the line 0-0'. Now D is determined by the intersection of rays D-B' 

 and D-B. The true curve is then easily constructed and pole 0' is located. 



If the bunker is surcharged by vertical walls as shown in (e) the curve is extended until it 

 meets the slope of the material, and the span and sag are to be used as shown. 



Deep Bins. For the calculation of the stresses in deep bins, see the calculation of the stresses 

 in grain bins, Chapter IX. 



For methods of calculating the stresses in hopper bins with the top surface surcharged, and 

 the calculation of the stresses in bin bottoms and circular girders, see the author's "The Design 

 of Walls, Bins and Grain Elevators." 



Angle of Repose. The angle of repose and the weights of different materials are given in 

 Table IX. 



DATA. For angles of internal friction, see Table IX, and for angles of friction on bin walls, 

 see Table X. 



TABLE IX. 



WEIGHT AND ANGLE OF REPOSE OF COAL, COKE, ASHES AND ORE. 



