14 



INFLUENCE DIAGRAMS 



Bottom Chord of Curved-chord Warren Truss. If both sets 

 of web members are inclined as shown in Fig. 7, the 

 influence diagram remains unchanged in its construction, 

 but the line EF does not coincide with the line DA as in 

 the previous case. 



FIG. 7. 



The criterion for the maximum moment produced by 

 wheel loads is found as follows : 



oX 



3 )+TF 2 (-tan 2 -{-tan 3 ) 



+ TF 3 tan 3 =0. (37) 



= (Wi+W 2 +Wz) tan 3 -TFi tan 0i 



-W 2 tan 2 =0, (38) 



Substituting the values of the tangents, equation (38) 

 becomes 



I. . . (39) 



