Plug weld check 5

[BAGW]

Hi,

I have a question regarding the plug weld design. Per AISC the base metal have to be checked per section J4. When I am checking the shear rupture for the base metal what area do I use?

Av = t x b
t = Thickness of the base metal
b = Perimeter of the plug weld hole?

Thanks

 

[BAGW]

Is there any example that addresses plug weld design? I could not find any. Checked all possible resources.

 

[KootK]

...plus the possibility of direct shear through the plug weld, assuming the load is placed on the outer bars.

1) A fine point that I agree with.

2) Technically, I think that there is always direct shear no matter which piece is loaded except for one, very particular situation in which all three pieces are loaded "just so".

3) Fortunately, the direct shear components are often pretty small relative to the shear flow components so neglecting the direct shear doesn't usually get folks into trouble. The situation can be a bit more dire with materials like wood where perpendicular to grain fastener performance can be worse than parallel to grain fastener performance.

 

[r13]

Is there any example that addresses plug weld design? I could not find any. Checked all possible resources.

Because there is no such/permissible structural connection at this point of time, not saying it's not possible in the future though. For weld itself, you shall check AWS for guidance.

 

[dauwerda]

Because there is no such/permissible structural connection at this point of time, not saying it's not possible in the future though

Of course plug welds are a permissible structural weld, that is why they are addressed in AWS D1.1 and the AISC Steel Manual. It is only permissible to load them in shear (parallel to the faying surfaces), but still permissible. They are typically used with fillet welds for large overlapping plates.

My steel textbook from college (McCormac) has one design example in it with overlapping plates loaded in tension that are fillet welded on the edges, and in order to develop the full strength of the smaller plate, a slot weld is also added in the middle of the plate.

 

[r13]

My mistake and lack of knowledge on the permission by code. Below is ASIC section J2.3:

3. Plug and Slot Welds
3a. Effective Area
The effective shearing area of plug and slot welds shall be taken as the nominal crosssectional area of the hole or slot in the plane of the faying surface.
3b. Limitations
Plug or slot welds are permitted to be used to transmit shear in lap joints or to prevent buckling or separation of lapped parts and to join component parts of built-up
members, subject to the following limitations:
(a) The diameter of the holes for a plug weld shall not be less than the thickness of...

 

[BAGW]

@ dauwerda,

Can you please share the book title? Or is you have that page handy can you upload the example? Thanks

 

[r13]

After reading AISC and AWS, I am still confused on how to check the plug weld and the connected part. However this article from Autodesk relieves my confusion to some extent, Link. Also, AWS D1-Series References to WPS for Plug and Slot Welds is linked here for further readings. Link

 

[dauwerda]

I don't think it has what you are looking for, but here it is ("Structural Steel Design" 4th edition by Jack McCormac)

 

[BAGW]

Great thanks