50 NOTES ON PLATE-GIRDER DESIGN 



For a web splic, :it M.me point other than tin center of 

 the girder, the numlx -r of rivets in the flange plates on 

 the side toward tin- center will In- the number required 

 for splicin.i: the web; on the side toward the end the 

 number will be the sum of those for connecting flange to 

 web plus those for web splicr. 



The extreme fiber stress on the web for a moim-nt 

 of 6,300,000 ft.-lb>. was Hi.0()0; fora moment of .'5,400,000 

 ft.-lbs. it is 8630. For the strip of web between the flange 

 angles tlie previous determination is evidently ample. A 

 study of the stress intensity at different points in the 

 web for this condition of loading would show that the 

 a intensity was nowhere as great as for the case for 

 which the splice was designed. 



A safe resultant rivet bearing of 9190 should not be 

 exceeded. 



The vertical component on a rivet at either edge of 

 the main splice plates will not exceed 75,000/54 = 1390 

 Ibs., the horizontal component =3.5 X & X8630X 38/48 Xj 



v : 



= 3480 per rivet. The resultant - v 1390" +3480" =3800. 



PROBLEMS 



9a. What is the relative efficiency of the unriveted plate of Fig. 

 9a to that of the section of the plate through the first vertical line of 

 rivets in the splice. 



Ob. Compute and compare the resisting moment of the rivets in the 

 splice of Fig. 9a with that of the net section of the web plate through 

 the first vertical line of rivets. 



9c. Make a sketch of a splice for the girder, using only two vertical 

 rows of rivets on each side of the splice. 





