l6o TOWERS AND TANKS FOR WATER-WORKS. 



The sizes and spacing of rivets for marine-, boiler-, and 

 tank-work, requiring water- and steam-tight joints, is some- 

 what different from that demanded for structural work, such 

 as bridges, buildings, and towers. For structures of the latter 

 type, the following general rules are applicable : 



RIVET-SIZES AND SPACING FOR STRUCTURAL WORK. 

 (DU BOIS.) 



Diameter of rivet-hole : Not less than thickness of thickest 

 plate through which it passes. For cross-girders, stringers, 

 compression-members: f- to J-in. rivets. 



General rule: Diameter of hole = ij thickness -\- T 3 ^ in. 



Number of rivets: Divide total .stress transmitted by joint 

 by product of diameter of rivet by thickness of plate by safe 

 bearing-value per square inch of rivet material. 



For number of rivets to resist shear: Divide total stress 

 by product of area of rivet, by safe shearing-value. (Shearing- 

 values used in practice are 6000 to 7000 Ibs. per square inch.) 



RIVET-SPACING FOR STRUCTURAL WORK. 



Assume shearing strength equal to tensile strength. 



/ = pitch ; d = diameter of rivet ; / = thickness of plate, 



ci 

 and a = section of rivet. / = --- -|- d. 



Practical restrictions: Rivets should not be closer than 3 

 diameters, nor more than 6 inches, centre to centre. In com- 

 pression, never more than 16 times thickness of thinnest out- 

 side plate. Distance from centre of rivet-hole to edge, end, 

 or next row of rivets should not be less than 2 diameters of 

 rivet. The following table is the Carnegie Steel Company's 

 practice for structural work : 



