366 STEEL STAND-PIPES AND ELEVATED TANKS ON TOWERS. CHAP. XI. 



The stress per lineal inch will be 



S" = I.o6h*/d 



(8) 



If the allowable stress in the net section of the plate is 12,000 Ib. per sq. in., and e = efficiency 

 of joint, then from (2) 



t = 2. 6h-d/ (12,000 X e) (9) 



where values of e for different conditions are given in Table I la. 



Formulas for Stresses in Elevated Steel Tanks. The stress per lineal vertical inch of plate 

 is the same as in stand-pipes 



S = 2.6h-d (i) 



and the unit stress in vertical joints is 



5 = 2.6h-d/t (2) 



Stresses on Radial Joints. Spherical Bottoms. In a hemispherical bottom the radial 

 stress per sq. in., TI, "will be one-half the stresses in a cylinder of the same radius and the same 

 internal pressure. 



TI = 2.6h-d/(2t) = 2.6h-r/t (10) 



In a segmental bottom (b) Fig. I , the stress 7Y will be 



TF-cscfl T 



2 X I2ir'b't 247TT1'/ 



Now W = 62.5&-7T-& 2 = 62.5&-7r-ri 2 -sin 2 0, and 



(II) 



(12) 



which reduces to equation (10) for a hemispherical bottom when r\ r. 



- A 



CONICAL BOTTOM 



(b) 5EGMEHTAL BOTTOM 



FIG. i. 



