SIMPLE TRUSSES 



the vertical through the right end of the cut stringer is the 

 value of d'. This is easily shown as follows: Fig. 1. 



mn:h::d':d, or d' =-mn=MN; . . (17) 



but 



MN :s::h : s+6, or MN = } -h; . . . (18) 



therefore 



(19) 



which is the value given in (16). 



Neutral Point. The position of a load which produces 

 no stress in the web member UL' is indicated by the point 

 G in the influence diagram, Fig. 1, since a load in the truss 

 immediately above G produces no stress in the member 

 as shown by a zero ordinate in the influence diagram. 

 The point ra'shown in the truss diagram is directly above 

 G. This point is located by the intersection of the line 

 MN' and the diagonal drawn as explained in determining 

 d'. Let x' be the horizontal distance from m' to the vertical 

 through the right end of the cut stringer, and H+x r the 

 horizontal distance of m' from the vertical through the 

 right support of the truss. Then in Fig. 1 



m'n'ihiix'id, or m'n' ~x' =MN(H+x')\', (20) 



but 



MN :s::h:s+b, or 



(21) 



