26 INFLUENCE DIAGRAMS 



The criterion for wheel loads producing maximum 

 moment is 



(60 



The Length of the Cut Stringer for trusses with sub- 

 struts or sub-hangers of the type considered above, can 

 be readily determined by the following rules. 



(a) For diagonal members: whenever the section cuts 

 the segment which is a part of the main diagonal and also 

 a part of the auxiliary truss, the length of the cut stringer 

 is the horizontal projection of the segment cut. 



(6) For diagonal members: whenever the section cuts 

 the segment which is a part of the diagonal of the main 

 truss and forms no part of the auxiliary truss, the length 

 of the cut stringer is the horizontal projection of the diagonal 

 of the main truss. 



(c) For chord members: whenever the section cuts the 

 chord which forms a part of the main truss chord and 

 also a part of the auxiliary truss, the length of the cut 

 stringer for this chord is the horizontal projection of the 

 diagonal segment cut by the section. Otherwise the 

 length of the cut stringer is the horizontal projection of the 

 chord, of the main truss, which is cut. 



(d) For vertical members of the main truss: whenever 

 the section cuts any portion of the auxiliary truss the length 

 of the cut stringer is the horizontal projection of the diagonal 

 of the main truss. In case the section does not cut the 

 auxiliary truss the length of the cut stringer is the horizontal 

 projection of the segment of the diagonal adjacent to 

 the vertical. 





