Design of Column Shear Lugs.

[dik]

I'm looking at the use of stub W section 'lugs' welded to the baseplate of larger W shapes to improve the transfer of high lateral loads (100 kips approx). This is in conjunction with high uplift forces on the column (80' tall building with little dead load). Uplift also in the magnitude of 100 kips. Also info on the design of 'grout pockets' to accept the lug.

Can anyone provide a source for literature, papers, pdf file, etc. (LRFD preferred, but ASD info OK, too).

Dik

 

[neffers]

AISC Design Guide #1 talks about the design of shear lugs.

neffers

 

[Stillerz]

I'd say Design Guide 1 also but I do not think that using "W' stubs is covered.
Sounds like a good idea though.
The design of conventional plate shear lugs is covered in DG1 and is rather straight forward. I'm sure the concepts could be adapted for your application.
Watch out for DG1, second edition. There are more errors in it than in the movie Major League.

 

[Lion06]

dik-

Are these columns going into piers, grade beams, ftgs, caissons? Is this a braced frame bulding?

I have a pretty slick detail that goes along with a schedule (for braced frames), but it won't work on isolated piers. If you have some length of concrete (like grade beams), it works very nicely. It's probably less expensive than blocking out for, and providing, shear lugs.

 

[Stillerz]

EIT-
Let us in on it!!

 

[dik]

It is a braced frame, going into piers cast into a foundation wall/gradebeam. It is a matter of confining the grout pocket with ties and vertical reinforcing.

Dik

 

[Lion06]

I'll send it to your email.

 

[Lion06]

dik-
Check your email. I attached the detail I was talking about and another that goes with it (especially if you have high uplift forces like this).

 

[jike]

I prefer to use a cast in plate with headed studs to transfer the shear. The anchor bolts go thru this plate and are the hold down fastening for the column base plate 2" above. Base plate is still grouted. Side plates are then field welded between base plate and cast in plate to transfer shear.

Easy to install.

No messing around with shear lugs which are not very often installed correctly!

 

[Lion06]

jike-

My detail is similar, but I use rebar welded to the embed plate because it's often hard to get headed studs to work with a long, relatively thin member (such as a grade beam) with App. D. I have an embed that take the shear through shear friction, and the column anchor rods take the uplift (lapping with additional reinforcement as required).

 

[jike]

I use 8" long, 3/4" dia. headed studs. If rebar, use ASTM A706, weldable rebar.

 

[CTW]

AISC Design Guide #7 also covers shear lugs.

 

[Lion06]

We have a general note that says all rebar to be welded is to be A706, and that welding electodes for welding rebar are to be E90XX.

 

[paddingtongreen]

The grouting problem can be handled with flowable grout. I have had holes drilled in some large plates, over the grout pocket, so that we could be sure it flooded the pocket as it filled the dam.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[StructuralEngGuy]

Similar to what Jike and StructuralEIT suggest, why not use a cast in plate with a shearlug? You don't have to mess with App. D if you do that.

 

[InDepth]

For lugs I typically like to use HSS sections. The contractor blocks out using styrofoam.

 

[KootK]

StructuralEIT: I would love to see your detail. Could you send it my way?