76 



HANDBOOK OF MECHANICAL DESIGN 



Limitations of the equations : 



1. Valid only for panels subjected to pure shear load. 



2. If /s exceeds the shear yield point of the material, shear yield point should be 

 taken as the critical stress. For 24 ST,' the shear yield point is 24,000 lb. per sq. in. 

 approximately. 



3. The equation does not give dependable results for sheets less than about 



0.032 in. thick. 



I 1 1 \ 1 1 i 



9 



8 1 -; 



7 --—,^^ 



5 



4 



3 ^ 



2 ^ 



i^ a ^—_-\-Stiffeners one side only 



Fig. 5. — Dimensions a and 6 on a typical shear resisting 

 web with chord and stiffener angles on one or both sides. 



0.1 0.2 03 0.4- 05 06 07 0.8 0.9 1.0 



Rafio -g 



Fig. 4. — Coefficient K for calculating .shear members, 

 for different values of b/o or n/ft. 



-J67-— 1 



43 



I 8,0001b. 



0064 web 



\ 4,0001b. 40001b 



Fig. 6. — Example of a typical shear 

 resisting web. 



EXAMPLE 



Dimensions of, and load on, a typical shear-resisting web are given in Fig. 6. 

 Assume Q/I = 0.1742, where Q is the statical moment, i.e., the summation of the 

 various elementary areas above the neutral axis times their respective centroid dis- 

 tance from the neutral axis. 



shear load X Q/I 



Applied unit shearing stress 



web thickness 

 0.1742 



= 4000 X og^ 



= 10,900 lb. per sq. in. 

 4.3 



From Fig. 4, 



h 

 a 



K 



0.064 

 4.3 



= 4,520 



36.7 



= 0.117 



= 5.51 for b/a = 0.117 

 _ 9,240,000 X 5.51 



4,520 

 = 11,250 lb. per sq. in. 



