Shear Lag in Moment Connection

[vmirat]

I'm reviewing a design for a moment connection where the engineer is welding plates to the edges of the flanges of a W21x101 beam and then welding angles to these plates which reach back to an existing concrete column. It seems to me that there would be shear lag in the flange of the beam but section F of the steel manual doesn't really talk about this.

 

[csd72]

Could you post a sketch, and explain exactly what you are referring to as shear lag( is it longitudinal or transverse?).

 

[vmirat]

Attached is a powerpoint showing the beam top view with the "wings" attached to the flange.

 

[csd72]

vmirat,

It is similar to what I imagined, but best to be sure.

So shear is taken by the vertical angle directly into the web and bending is taken by the horizontal angles welded to the wings.

The documents that I have seen regarding shear lag show it acting at 45 degrees to the beam axis. Therefore of your 9" is greater than half the width of the beam then it should be fine.

That said, if this is in a seismic region there may be other specific seismic issues that I am not aware of.