i 5 6 



TOWERS AND TANKS FOR WATER-WORKS. 



Example. Find the proper pitch for double-riveted joint, 

 in. plate and f-in. rivet: 



P= 



3712 X 2 X 40,000 



-[-.6875 = 2.6671 or 2% in. 



.2500 X 60,000 



In the example above, 40,000 Ibs. is taken as being a con- 

 servative value for a rivet in single-shear, and as allowing some 

 latitude for irregularity in shop-work. 



Size of Rivets in Relation to Thickness of Plates. The 

 determination of the size of rivet to be used as a fastener for 

 certain thicknesses of plates is not governed by any hard and 

 fast rule, but varies considerably in the practice of different 

 manufacturers. 



From investigation made by the United States Govern- 

 ment, the relation of thickness of plates to diameter and length 

 of rivets has been established by the Bureau of Construction 

 and Repair, Navy Department, as follows: 



[NOTE. Centres of rivets are spaced not less than if times their diam- 

 eter from the edges. In double- and treble-riveting, their distance from 

 centre to centre of rows (horizontal pitch) to be not less than 2^ diameters 

 in laps, and 2^ diameters for straps.] 



In the above table the length includes length of shank 

 necessary to form the field-head measured under manufactu- 

 rers' head, and for a "grip" equal to twice the thickness of 

 plate assumed. 



In order to facilitate calculations for water-tight metallic 

 joints, the following table, providing an efficiency of joint suit- 

 able for metallic reservoirs, and an auxiliary diagram of 

 details, has been designed by the author. 



