single plate connection to cap plate with tongue 1

[wrxsti]

I am trying check capacity of a single plate welded to column

The single plate is conventional

but instead of the connecting member being web of a wide flange, tee or whatever

its now a tongue extended from a cap plate of a hss

can i still use the conventional design checks for weld and bolt of the single plate?

and what about tongue to cap plate weld?
cap plate to HSS?

 

[strucbells]

Didn't you already have a thread on this? Provide a sketch, as I'm not following your description.

 

[KootK]

Like this? If so, I would think that there would be some additional checks to consider.

 

[dauwerda]

I interpret it more like this (column may be HSS or Wide Flange):

But, we will have to wait for the OP to clarify.

 

[KootK]

That would make more sense and would be more conventional.

 

[BAretired]

Maybe the plate is just an extension of the HSS cap plate. Who knows? What forces are acting on the plate? Sketch is needed.

If it's the way dauwerda shows, would need to check the web of the HSS column, probably using yield line method.

BA

 

[wrxsti]

yes it is as dauwerda sketched

 

[r13]

Other than the connection plate, the most problematic item is the HSS/column web, which can be the limit of your application.

 

[strucbells]

Agreed with r13, if you have an HSS column, you'll want to check the web of the column.

If you have the 15th edition of the AISC steel manual, reference J10.10 and pg. 9-14. If you have the 13th or 14th edition, it's in chapter K under..I think Part 2 (plate connections to rectangular HSS)?

The punching shear check is straightforward. The yield line check for flexure is a little more complicated. If you google "Carlo Lini yield line theory" there are a few free articles that help explain it.

 

[r13]

Does the code still allow thru plate connection for HSS?

 

[strucbells]

It's allowed, but it's apparently a lot more expensive to fabricate. A lot of the AISC connection design tips they put out emphasize to only specify that if you really need it for high loads.

 

[r13]

Agreed. It (thru plate) is a pain on the butt.

 

[wrxsti]

thanks for the responses guys

yea the design examples (K.6) have a good example for shear tabs to HSS

they only account for wall slenderness, shear yielding and shear rupture though

they also go on to analyze the shear tab as conventional using the tables

i was concerned if the above configuration would void the conventional configuration

and what eccentricity to put on the weld of the tongue and cap plate of the shear force

 

[BAretired]

Consider the bolt line to be a pin. That determines the eccentricity of both welds.

BA

 

[evo10]

i think the aisc for conventional shear tab
they consider the weld to the column concentric and the eccentricty from weld to centerline of bolts for the bolts

would the weld at the tongue to the capplate now be that eccentricity plus the distance from the bolt line to the weld on the capplate

 

[BAretired]

If the bolts are midway between the wall of the HSS and the cap plate, the eccentricity for both welds is the clear distance divided by two.

BA

 

[evo10]

so can i use conventional for the plate
then use eccentricity from the bolts to the tongue and cap plate

 

[wrxsti]

Thanks BAretired

 

[BAretired]

You're welcome wrxsti, but the tricky part comes in checking the HSS wall. Yield lines should look something like I have shown in the sketch below (red arrows show the direction of the fall line). It may be necessary to add a reinforcing plate over the HSS wall.

If the HSS wall is too thin, the plate will deflect until the bolts start resisting moment; however, I would not consider that to be a properly designed connection.

BA

 

[Celt83]

BA:
Do you have any recommended references for yield line analysis?

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