STEEL FRAMEWORK OF BUILDINGS 9 



to the columns, whenever such occur, by means of connection 

 angles which must carry the entire load. Shelf angles may be 

 provided for convenience during the erection. The free end 

 of such floor beams must be securely anchored to the walls. 



29. Plate Girders (see Part IV). 



DETAILS OF DESIGN 



30. Minimum Size of Material. No rolled shape or metal 

 of less thickness than J in. shall be used except for fillers. No 

 angles shall be less than 2J"X2"Xi" and no rivets, except in 

 beam connections and lacing bars, shall be less than f in. in 

 diam. (Pars. 33, 38, 45, 46.) 



31. Details of Joints. Main members of trusses shall be so 

 arranged around the joints that their neutral axes will meet 

 in a common point. 



All joints in riveted work, whether in tension or in compres- 

 sion, shall be fully spliced. 



32. Details of Connections. The strength of connections shall 

 be such as to cause the main member to fail should the combina- 

 tion be tested to destruction. No connection, except for lattice 

 bars, shall have less than two rivets. 



33. Rivets. In main members composed of angles the maxi- 

 mum diameter of rivet used shall not exceed one-quarter (J) 

 the width of leg through which it passes. Three-quarter (J) 

 in. rivets shall not be countersunk in plates less than f in. in 

 thickness and |-in. rivets shall not be countersunk in plates 

 less than ^ in. in thickness. 



Except in bed plates, no rivet shall be of less diameter than 

 the thickness of the thickest plate through which it passes. 



34. Rivet Spacing. The minimum pitch shall never be less 

 than three diameters of the rivet and, if possible, not iess than 

 3" for I" rivets, 2" for |" rivets, 2J" for f" rivets, and If" for 

 i" rivets. 



The maximum pitch of rivets, in the direction of the stress, 

 shall not exceed 6 in., or 16 times the thinnest outside plate con- 

 nected, and not more than 40 times that thickness at right angles 

 to the stress, except when two or more plates in contact are to 

 be held together, where the pitch may be 12 in. in any direction. 



The maximum pitch at ends of built up compression mem- 



