Oversized Holes with Flange Plate Moment Connections 1

[engjg]

I have read in numerous places it is common to provide oversized holes in the flange plates and standard holes holes in the beam flange for flange plate moment connetions. If this is done do you have to use slip critical bolts with respect to AISC 360 and/or AISC 341?

Or would you only have to provide slip critical if you have OVS holes in both plate and beam flange?

 

[ash060]

It would have to be slip-critical. AISC J3.2 states that oversized holes cannot be used in bearing-type connections. So any connection that has a ply with oversized holes needs to be slip-critical.

 

[engjg]

That is what I would have thought. I am questioning because AISC 360 manual part 12 and AISC 358 chapter 7 speak to specifically to providing the ovs holes in only the plates (not beam flange) and no mention of the requirement to use slip critical? AISC 358 chapter 7 speaks also to excluding threads from shear plane right after mentioning OVS holes which would make you believe they are not thinking of slip critical? If you were going to use slip critical why not use oversized holes in beam flange too?

fyi... my question is general not just specific to seismic i.e. AISC 341/358

 

[JoshPlumSE]

Well, AISC 358 connections are based on testing. And, it's also based not on applied force levels, but on capacity of the members. Therefore, I don't believe the slip critical concept would apply to it unless it's part of the design procedure and / or shown in their design example.

If it's neither, then you could probably get away without designing the connection slip-critical even for non-seismic connections. However, you would definitely want to using fully tensioned bolts.

 

[wannabeSE]

For seismic, see AISC 341-10 section D2.2. With few exceptions, standard holes or short slots perpendicular to load are required. Bolts are designed as bearing bolts. They are pretensioned with fraying surfaces prepped same as slip critical.