DESIGN OF END CONNECTIONS. 



References. 49, p. 58; 78, 79, 80, 81, 85, p. 60; 40, 41, p. 141; 60, J 62, p. 142; 

 5 63, 64, 65, 66, 74, p. 143; 18, 19, p. 209; 37, 39, 40, p. 210; $ 41, 5 42, J 52, p. 211; 

 71, p. 212, p. 219, p. 223; Tables 106 to 119 inclusive. 



Strut or Tie. Design the end connection for a 4" x 4" x %" angle, carrying a stress (either 

 triiMkr or compressive) of 40,000 lb., the angle being fastened by both legs to a % in. plate as shown 

 in Fig. 2, using % in. rivets. 



Solution. The allowable stress on one % in. rivet in single shear is 5,300 lb. and in bearing 

 s in. plate is 6,750 lb., using 12,000 lb. per sq. in. and 24,000 lb. per sq. in. as the allowable 

 stresses in shear and bearing, respectively. Table 114. The shear evidently controls, and the 

 number of rivets is 



40,000 



5-300 



7.6 or 8 rivets. 



Four of these will be placed in the main angle and four in the lug angle. In order to transfer 

 the proper portion of the stress to the lug angle, the number of rivets between the main angle 

 and lug angle must be equal to the number of rivets in the lug angle, or four in this case. 



If the angle is connected by one leg only the eight rivets will be put in one leg as shown in 



Fig- 3- 



Pin-connected Top Chord. Design the end connection for the top chord of a pin-connected 

 bridge as shown in Fig. 14. Length center to center of pins = 25' o". Rivets Y$ in. 



Solution. The connections should be designed to carry the full strength of the member and 

 not the stress that it carries. The allowable unit stress is/ c = 16,000 70 l/r = 16,000 70 X 



- = 13,420 lb. per sq. in. Total stress = 13,420 X 51.84 = 695,700 lb. 



O.I2 



The entire stress of 695,000 lb. must be transferred from the member to the pin through the 

 pin plates and web plates. In the body of the member the stress is distributed among the dif- 

 ferent parts in proportion to the gross area, or as follows: 



F- 



Zm.Pb.ZOxi 



2 Top 4x4 XK" 



Are a of Sectional. 84/n.* 

 Leastfec/ius 



of Gyration = 8J2/n. 



FIG. 14. END CONNECTION OF TOP CHORD. 



39 



