Do shear plates need to be welded to the beam web for OMF beam to column connection? 2

[Kom3]

Hi, I am wondering if the beam web needs to be welded to the shear plate for an OMF connection. If yes, which provision requires this?

Regards,

 

[ProgrammingPE]

I don't see anything that would mandate welds to the shear plate as long as the bolted shear plate is able to meet the shear strength requirements per AISC 341-16, Section E1.6b.

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[BAretired]

Without the fillet weld, the bolts could slip into bearing after the CJP welds have been completed, so I believe it has merit. In fact, I would be surprised if it is not a code requirement (but I don't know).

BA

 

[ATSE]

Kom - could you clarify, is your retrofit frame beam connecting to the weak axis of the column?

 

[Kom3]

@ATSE

Yes, the beam is connecting to the weak axis of the column.

Regards,

 

[ATSE]

Regardless of what the code says or local practice allows, weak-axis moment connections are sketchy. Even for low seismic. Does AISC have any clear guidance on this? If you find decent litereature, please post it for the rest of us. I hope I never get cornered into doing this.

 

[human909]

I can't answer the question directly as I don't know your code. But if you don't weld the shear plate then you are essentially relying on the flange welds for a fair bit of the shear. Remember a bolt in bearing is not a completely stiff connection in this context you need a non negligible amount of movement before the bolts sit down in their holes and start taking load.

 

[ProgrammingPE]

Your concern about the bolted web connection being less stiff than the flanges is reasonable, but testing has shown that that is not a problem for these connections (see quotes below from Modern Steel).

Modern Steel Article

A common misconception is that slip-critical joints are necessary at the web connection to limit the vertical movement of the beam after the flanges have been welded. This would presumably prevent secondary bending and shear stresses in the beam flange in the area between the column flange and the weld access hole. However, the tests showed no decrease in strength when bearing joints were used. Furthermore, most of the tests with slip-critical joints had slip occur at some point in the testing, effectively rendering the web connection a bearing joint anyway.

...tests have shown that these connections can carry moments greater than the plastic capacity of the beam, even when combined with shear loads approaching the shear yield strength of the beam.

Also, AISC's Steel Manual does not show fillet welds to the web connection in their examples.

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