Doubler Plate Weld 1

[WARose]

Been a while since I have done one of these.....am confused on the weld. Not worried about the weld to the web: it's a full-pen to stiffener that is full-penned to the web. Am sort of worried about the weld on the flange side of the doubler.....because quite frankly, I cannot find much guidance here (unless it is a special moment frame in a seismic situation, and this isn't). So what should the weld strength be on that end? Thanks.

 

[KootK]

Given that doublers mostly function as pure shear panels, I believe that your unit shear transfer capability should be the same on all sides of the doubler plate.

 

[WARose]

That's a good point but I have to wonder (given the point here is to resist diagonal buckling of the panel zone).....is that really necessary? What unit shears would it really be resisting on that side? (except to provide side restraint for buckling.)

 

[KootK]

No matter what the specific purpose of the doubler is, once you make the connection, I think that it's appropriate to assume that it sees its rightful share of the shear demand and handle the welds accordingly. You can't do much to stop the doubler from absorbing loads and welds generally aren't ductile enough that they can adapt to significant overload.

 

[WARose]

Good point KK.

 

[sbisteel]

AISC Design guide 13 also says that the vertical weld along the column flange edges should be sized for the required strength of the doubler plate (i.e. full demand minus the column panel shear strength) for non-seismic applications.

Not that you asked, but I've always preferred to provide a thick doubler and fillet weld the plate to the flange of the column:

 

[WARose]

I'll probably change it to a plug weld (with the plate set back a bit). Thanks all.