142 W. H. WARREN. SOME APPLICATIONS OF THE 



Section. Tons. 



6 -F 8 * 160-14(1 (7 + 6)100- 



(120 + 140)^ = r 3 = + 8;53 



7 -X 4 x 24 + 14{(f 60-40) + (-«,60 



-20) + (f.60)}=0 X 4 --= + 4:3-75 



+ ^ 4 x 26-5 + 14{(|.80-60) + (f. 



80 - 40) + (£. 80-20))-= Z± = - 31-70 



+ \\ x 139-14(1(7 + 6 +"5)100 



-(120 + 140 + 160)} =0 T 4 =-19-64 



8 -F 4 x 180-14(|(7 + 6 + 5)100 



-(120 + 140 + 160) \ = F 4 = + 15-17 



■9 - X, x 27 + 14((£. 80 - '60) + (f. 



80-40) + (&80-20)+£.80}=0 X 5 = + 51-85 

 + Z 5 x 23-5 + 14 {(£. 100 - 80) + 

 (f, 100 -60) + (£.100-40) + 

 (a 100-20)1=0 ^, = -44-68 



+ F 5 x 128 + 14.|(l + 2 + 3+4) 



x 100 = Y s =- 13-67 



10 - r 5 x 160 + 14.^(1 + 2 + 3 + 4) 



100 = F 5 = + 10-94 



11 -X 6 x 24 + 14{(|.100-80)+(f. 



100 -60) + (-§.100 -40) +(f. 



100 - 20) + f . 1001 =0 X G = + 65-63 



+^ 6 x 20-6 + 14{(£ 120 J - 100) +(f. 



120 -80) + (f. 120 -60) + (f. 



120-40)+ (|. 120-20)]=0 Z 6 = -50-97 

 + F 6 x 108 + 14.1(1 + 2 + 3 + 4+5) 



x 100 = T 6 = - 24-31 



12 - V 6 x 140 + 14.1(1 + 2 + 3+4 



+ 5) x 100 = F 6 = + 18-75 



-X 7 x21 - 14. |(l + 2 + 3 + 4 + 



5 + 6) x 40 = X 7 = + 70-00 



13 -Z 7 x 18-5-14.1(1 + 2 + 3 + 4 



+ 5 + 6) x 40 = ^ 7 =-79-46 



Plate 6 shows the total stresses developed in the various portions 

 of the structure, and the areas and sections provided to resist 

 them. There are several matters in connection with the design 

 of this bridge which will now be considered. 



1. The shrinkage of timber in length is provided for by double 

 wedges at the end of each strut. 



2. The shrinkage in the length of the upper chord would pro- 

 duce sag in the whole truss, but this can be neutralized by screw- 

 ing up the suspension bolts. 





