SIMPLE TRUSSES 



21 



Vertical of Sub-hanger Truss. In Fig. 13, the cut stringer 

 for the vertical UL is the horizontal projection of LL', 

 since no part of the load on L'L" is supported at L. The 

 construction of the influence diagram follows the general 

 rule. In determining x' and d' from the truss diagram, h' 

 and the diagonal UL' form no part of the truss proper. 



. 



The criterion for wheel loads producing maximum 

 moment is 



W 



d' 



(52) 



Bottom Chord of Sub-strut Truss. The bottom chord L 4 Ls 

 in Fig. 14 is a part of the chord of the main truss and also 

 a part of the chord of the auxiliary truss L 3 FI/5. Con- 

 sidering only the chord L^Ls of the main truss the influence 

 diagram is DABD. Now considering the chord LLs 

 of the auxiliary truss L 3 VLo and taking the center of 



