Hence 



SIMPLE TRUSSES 



W W, -& 



15 



(40) 



If s-b=%d, then 



Trusses with Sub-divided Panels. The usual type of truss 

 with sub-divided panels has one set of web members vertical. 

 The trusses here considered will have one set of web mem- 

 bers vertical and the chords not parallel. The only dif- 

 ficulty in constructing the moment influence diagram is 

 the determination of the proper length of the cut stringer. 

 This once determined the construction of the diagram follows 

 the general rule. 



Lower Segment of Diagonal in Sub-strut Truss. Let VL", 

 Fig. 8, be the lower segment considered. This is a portion 

 of the diagonal UL" of the main truss and also forms a 

 chord member of the auxiliary truss LVL". 



Considering the member VL" as a part of the diagonal 

 of the main truss, the influence diagram DD'FBD is 

 constructed in the usual manner. The auxiliary truss 

 LVL" may be considered as a simple truss supported at 

 L and L". The center of moments for VL" may be 

 taken anywhere in LL" or LL" produced and in order 

 that the lever arm of VL" shall be the same as that for 

 UL" the center of moments will be taken at the inter- 

 section of UU" and LL" produced, the center of moments 

 for UL". The influence diagram, constructed according 

 to the general rule, is D'EB'. Combining the two diagrams 

 just constructed, the final influence diagram for VL" 

 is DEFBD. This diagram is the same as if constructed 



