CAMBRIA STEEL. 95 



If c is the vertical depth of the web in the clear between the 

 fillets which connect it with the flanges, the square of the length 

 of the column to be considered will be 2c 2 . 



Substituting this value for I 2 in the formula for long columns 

 12000 



1 3000 t 2 

 we have 



12000 



T 1500 1 2 

 in which 



p = intensity of vertical shear, in pounds per square inch = 



Total shear in pounds 

 dt. 



c = depth of web in clear between fillets in inches, 

 t = thickness of web in inches. 

 d = depth of beam in inches. 



This formula is also applicable for computing the safe shearing 

 stress in the webs of plate girders, in which case the length, 1, is the 

 vertical distance between centers of upper and lower rows of 

 rivet holes connecting the webs and flanges. 



The webs of plate girders should be reinforced by stiffening 

 angles at points of support and concentrated loading, and in 

 cases where the intensity of shear exceeds that given by the above 

 formula the web should be provided with stiffeners. 



The following tables have been prepared based upon the above 

 formula for safe unit shearing stress in the webs of beams and 

 channels. 



