24 



INFLUENCE DIAGRAMS 



The criterion for wheel loads producing maximum 

 moment is 



(57) 



FIG. 15. 



Top Chord of Sub-hanger Truss. Referring to the expla- 

 nations given for Fig. 14, the horizontal projection of 

 UV, Fig. 16, is taken as the length of the cut stringer 

 and the influence diagram constructed according to the 

 general rule. 



The criterion for wheel loads producing maximum 

 moment is 



W_Wi W 2 (s-b) 



I " s + " sd ' 



(58) 



If s-6=2d, then 



W Wi+2W 2 

 I " s 



(59) 



