SIMPLE TRUSSES 



19 



of the cut stringer. The graphical determinations of d' 

 and x are clearly shown in Fig. 10. 



The criterion for wheel loads producing maximum 

 moment is 





(49) 



Upper Segment of Diagonal in Sub-hanger Truss. The 

 member UV in Fig. 11, is a part of the diagonal UL" of 



FIG. 11. 



the main truss and also a chord member of the auxiliary 

 truss UVU". The influence diagram for UL" is DEF'BD 

 and that for the chord UV is D'FB'. The combination 

 of these two diagrams gives the influence diagram DEFBD. 

 This diagram is constructed according to the general 

 rule when the horizontal projection of UV is taken as the 

 length of the cut stringer. The graphical determination 

 of x' and d f requires no explanation as the constructions 

 are evident in Fig. 11. 



