DOUBLE INTERSECTION TRUSSES 



37 



magnitude but opposite in character. The magnitude of 

 this component is equal to the difference between the 

 horizontal components of the stresses in the chords in 

 the panel containing the diagonals being considered and the 

 adjacent panel opposite the point of intersection of the 

 diagonals. In Fig. 27 the horizontal components of the 

 diagonals UsM 2 and M 2 L% is the difference between the 

 horizontal components of the chords in this panel and the 

 panel immediately upon the right. 



FIG. 27. 



The influence diagram for the horizontal component 

 of U^Ut and L 3 L 4 can be constructed according to the 

 general rule by laying off CD equal to s + h 2 . On DB as 

 a base construct a similar diagram for the chords U 2 U3 

 and L 2 L 3 , the difference between these diagrams as shown 

 by the shaded areas in Fig. 27 being the influence diagram 

 for the horizontal components of the diagonals U 3 M 2 and 

 M 2 L S . The stress in any diagonal equals its horizontal 

 component multiplied by the secant of the angle it makes 

 with the horizontal. 



