INSTRUCTIONS TO DRAFTSMEN, C. M. & ST. P. RY. 221 



(1) Splices shall always be located at points where there is an excess of flange section. 



(2) No two parts of the ilaii^e shall be spliced within 2 ft. of each other. 



(3) Flange angles shall be spliced with a splice angle of equal section riveted to both legs of 

 the angle spliced. Where this is impossible, the largest possible splice angle shall be used, and the 

 difference made up by a plate riveted to the vertical leg of the opposite angle. 



(4) In splicing cover plates where one or more plates intervene between the splice plate and 

 the cover plate which it splices, the requirement of paragraph 57 of the A. R. E. A. Specifications 

 for Design shall be-observed. 



(5) Rivets in splice plates and angles shall be located as close together as possible, in order 

 that the transfer may take place in a short distance. 



(6) No allowance shall be made for abutting edges of spliced members of the compression 

 flange. 



6. Flange Riveting. Rivets connecting flange to the web shall be sufficient to resist at any 

 point the longitudinal shear combined with any load that is applied directly to the flanges. The 

 wheel loads where ties rest directly on the flanges shall be assumed to be distributed over 3 ft. 



The pitch of rivets between flange and web at any section may be computed by the formulas: 



For through girders, p = R d/S. 



D 



For deck girders, p 



P = longitudinal spacing of rivets in inches; 



R = value of one rivet in bearing or double shear in pounds; 



d = distance center to center of flanges in inches; 



S = total maximum shear in pounds at the section, reduced in the ratio of the net area of 



flange angles and plates to the net area of flange plus J the gross web section. 

 W = one wheel load plus 100 per cent impact. 



7. Maximum Spacing. Maximum spacing of rivets between flanges and web shall be: 



Top flange, deck girders 3^ in. 



Top flange, through girders f 4 J in. 



For convenience in shop work, spacing of rivets in top and bottom flanges shall be exactly 

 alike where possible. 



8. Rivets in Cover Plates. Where it is necessary to compute spacing of rivets connecting 

 cover plates to flange angles, the following formula may be used: 



p = n R d/S X Ala 



where R = value of one rivet in single shear or bearing; 



n = number of rivets on one transverse line through cover plates and flanges; 



a = total area of cover plates at section; 



A = area of entire flange at section; 



S and d, as in section 6, "Flange Riveting." 



The pitch as computed by this formula shall be diminished 15 per cent for every cover plate 

 more than one. Rivets in cover plates shall preferably stagger half way with the rivets in the verti- 

 cal legs of the flange angles. The maximum spacing shall be 6 in. 



9. Circular Ends. For through spans with circular ends, the end angles should be spliced near 

 the ends, as the full length angles cannot be handled in making the bends. 



Rivets through cover plates on circular ends must be spaced close enough to draw the plates 

 tight against the angles. The smaller the radius, the closer rivets should be spaced. 



10. Overrun of Angles. In plate girders whose top flange is composed of four or more angles, 

 about I in. should be allowed between the edges of angles to allow for overrun. 



11. Gage in Cover-Plates. On girders which are similar, but which have webs of different 

 thickness, the gage in the angles should be left the same and the gage in the cover plate varied to 

 suit the web thickness. 



GIRDER STIFFENERS. Intermediate Stiff eners. Intermediate stiff eners, except at con- 

 centrated load, may be offset, and shall bear tightly against top and bottom flange. The ordered 

 length of offset stiffener angles shall be the finished length plus the thickness of each angle over 

 which it is offset. 



Size of Stiffeners. In general, the minimum size of stiffeners bearings against 6" X 6" 

 flange angles shall be 5" X 3$" X I", and against 8" X 8" flange angles shall be 6" X 3i" 

 X I". 



Field riveted stiffeners at floorbeams of through girders may have J in. clearance at the top. 

 Fillers under end stiffeners and under concentrated loads must bear on bottom flange, but may 

 have i in. clearance at top. 



