HSS Localized Yielding from Shear Plate

[DevonC90]

I am designing an HSS column which has a vertical plate with a shear load welded to the column wall. Looking in AISC 14th edition, Table K1.2 on page 16.1-144, it says that the limits are for the plate (which is all set) and the HSS punching shear, which gives the formula in the table. However, this formula is not dependent on the plate's shear load.

My question is shouldn't the thickness of the column wall be dependent on the shear load, since it would be localized? It does say to see Chapter J to calculate Rn, but frustratingly doesn't specify where. Can anyone point to the correct formula, if one exists, to calculate the shear load limit dependent on the HSS column wall thickness?

 

[mike20793]

If it is an all welded connection, then the capacity of the connection is the capacity of the welds themselves to the connected materials. The strength of welds are defined in Chapter J. You are checking the plate for it's limit states in accordance with the table, but you would also have to check what the plate is connecting to, whether it's the web of a wide flange shape or some other connection geometry. The formula given in the Table K1.2 (mine doesn't have a formula btw, was this included in a subsequent printing?) checks the capacity of the wall at the punching shear limit state. You're comparing the resistance based on a set wall thickness to the actual load. If the resistance isn't enough, then you need to increase the wall thickness. I hope that helps and I wasn't misunderstanding the question.

 

[DevonC90]

mike20793 My AISC manual is the 14t edition printed in June 2011. The condition in Table K1.2 is for a longitudinal plate T-connection under plate shear load, and the limit states are Plate Limit States and HSS punching shear. They give the formula for HSS punching shear, which is dependent on the thickness of the shear plate and wall thickness.

It says to calculate Rn, see Chapter J. So what I was unsure of is did they mean for the limit of the plates, welds, column or all three? I know how to check the welds and the plate for its limits, its the HSS I'm not sure of, maybe it doesn't need a check other than punching shear, I'm just surprised that it doesn't take the load moving from the weld to the edge of the column into consideration (I have a 74.2k load using a 3/8" shear plate into an HSS 6x6x1/4). I just find it odd there isn't some check for the column wall deforming under such a load.

 

[wannabeSE]

Have you looked at Example K.6, Single-Plate Connection to Rectangular HSS Column, in the design examples for AISC's 14th edition?

https://www.aisc.org/globalassets/product-files-not-searched/manuals/design-examples-v14.2.pdf

 

[JedClampett]

You might want to take a look at thread172-418241.
Oh yeah, I forgot, multiple posting is discouraged.

 

[BAretired]

Looks like a good application for Yield Line Theory.

BA

 

[SJBombero]

Larry Muir's "steelwise" column in Modern Steel Construction December 2014 number 5.2.2 covers this topic. The yield strength of the plate Fyp in equation K1-3 may be replaced with the actual maximum stress in the shear tab for a less conservative result.