STRESSES IN PRATT TRUSS 



Fig. 46, are found in the same manner as for a Warren truss. The 

 member f/ L acts as a hanger and carries only the load at its lower 

 end. The stresses in the chords are found by multiplying the coeffi- 

 cients by W tan 0, and in the inclined webs by multiplying the co- 

 efficients by W sec 0. The stresses in the posts are equal to the ver- 

 tical components of the stresses in the inclined web members meeting 

 them on the unloaded chord. 



U +4 U 2 +4| U3 + 26.S Ul +25.6 D! 



Rfl 



K--20-0--* 



Dead Load Coefficients Dead Load Stresses 



Dead Load =81bns per Joint- Sec9 = l-28- Tan 0=0-80 



(a) 



+ 4 Uz +4j U 3 +57-6 uk+5J.2 L)i 



RYT2 ~ 2 * Ll ~ 2 ^ u "^ U " ^ " "- 1 """"^|'R & 



Live Load Coefficients and Stresses 

 Live Load =l61bns per Joint- Sec0 = l-28-Tan9'0'80 



(b) 



+ 76-8 U 2 +86-4 Us +28 8 Uz +25-6 D! 



48 ' l ~ 48 ' ~ 76 ' 8 L ~ 25 ' 6 



Maximum Stresses Minimum Stresses 



(C) 

 FIG. 46. 



