Built-up Box Shape - PJP weld

[slickdeals]

I am in a situation where I need to make a 5x3 shape with plates because the axial loads are high and the size cannot increase due to glazing profiles.

I have it made up with two 4.25" x 3/4" plates and two 3" x 3/8" plates. I plan to do a PJP weld of the 3/4" thick plate to the 3/8" thick plate. I am wondering if there are any checks to be done in terms of sizing the welds. The entire section is in compression, but has very small out-of-plane moment (around 6 k-ft). A small weld would work for that using shear flow.

Would going with a 1/4" PJP be okay or should I upsize it to 3/8"? The axial load is around 140 kips.

 

[OHIOMatt]

Could you use an L5x3 1/2 x 3/4 and just have the 3 1/2" leg trimmed to 3"?

Sorry, for not answering the actual question, but this was the first thing that came to mind.

 

[OHIOMatt]

Ignore the post, I misread. Sorry

 

[PAstructural08]

Why not just use a fillet weld? Depending on the length of welds that could be a lot of preparation

 

[slickdeals]

Are you saying I should shorten the 3" plate to say 2.5" and provide a 1/4" weld along the length?

 

[jayrod12]

I would think that would be as effective as a PJP and a hell of a lot less work

 

[PAstructural08]

I'm not saying what plates to change; But if you only need a small weld than I think a fillet weld would be the best way to go. If this will be field welded than fillet welds are much more easy. You still need to design the weld for the capacity you need.

 

[connectegr]

I would second the fillet weld suggestion. You can calculated the shear stress and the weld to determine the weld size (VQ/I). Typically a continuous weld weld is not required.

http://www.FerrellEngineering.com

Providing fabrication and erection efficient structural design of connections. Consulting services for structural welding and bolting.

 

[KootK]

Depending on your loading situation, you may want to consider:

1) End welds to deliver the axial compression to the parts of your column in proportion to their area and;
2) Weld spacing suitable for composite resistance to buckling as well as the applied load.