Shear Lag Factor for Angles

[dozer]

When computing the shear lag factor, U, for an angle, AISC 360 14th ed. shows just one x bar (x with a line over it) in their diagram. I've looked at a few other references and found the same thing. Way back when dinosaurs roamed the earth and I learned about shear lag factors you took the maximum of two orthogonal x-bar distances. See link for an illustration from "Steel Structures Design and Behavior", 4th ed., Salmon and Johnson.

Link (I had to insert this manually, neither image or attachment is working.)

Has this method changed? When did that happen? Why didn't anyone tell me?

 

[phamENG]

I have the 5th edition, and the same figure is present. It is interesting because x_bar1 will always be larger in equal leg angles and unequal with the larger leg attached to the gusset, and will therefore produce the more conservative result. The image is not directly discussed in the text - it only directs you to the commentary of 360-10. Perhaps it was found to be overly conservative? Or, because these are all based on connections with more than one bolt, there is some inherent fixity that qualitatively removes the effect on eccentricity due to x_bar1? Just spittin' in the wind here.

 

[r13]

Single bolt connection has been barred since 199?.

 

[r13]

And now the shear lag effect covers weld as well.