AISC- coped beam checks

[a2mfk]

I have several standard W shapes that are part of a composite floor system, and the beams framing into the girders are being coped at the top flange mostly, but some at both top and bottom. I am not the EOR only the specialty engineer in this case. The connections are simple bolted shear connections.

I am working my way through the different coped beam checks and I am a little confused by the section on pgs 9-18,19 (13th ed black book) that deals with local web yielding and web crippling.

Specifically, the terms:
N- bearing length: what does this mean exactly for a coped beam and a bolted shear connection?

This N term is also used in Table 9-4, far RHS column, and at the top of the table it says (N=3-1/4), further confused.

x- distance at which compressive force is applied. Is this the compressive force resultant from the shear at the connection via a couple, in the top flange or along the cope?

I have searched through AISC, the commentary, etc. and not gotten any clarification, but maybe I have not looked in the right area. I am not sure why they didn't do a diagram/sketch for this check like they did for the others.

Anyone willing to post a sketch with these constants labeled or otherwise clarify this? Thanks!

 

[CTW]

N is the bearing length for a connection where the beam bottom flange is resting on another surface. It doesn't apply to bolted shear connections. The compressive force is the actual load applied at a distance from the end of the beam.

 

[a2mfk]

Thanks CTW, I was sorta thinking it did not apply to bolted shear connections but I was not sure. A simple diagram/sketch would have been great!

So does that mean with a bolted shear connection I do not have to check for local web yielding and web crippling?

I did all of the other checks... This would make sense to me anyway, block shear should control.

 

[a2mfk]

BTW- I did not mean for you CTW to provide a sketch, I meant AISC...

 

[CTW]

I know you didn't mean for me to provide the sketch. I have one somewhere though. If I find it, I'll post it.

 

[a2mfk]

So those checks don't apply in a shear connection, only for bearing conditions...?

 

[ash060]

Yes, they only apply to concentrated loads. For the coped flanges the checks are given in pages 9-6 thru 9-9 in the 13th Edition Manual. Table 9-2 gives Snet for various sections.

 

[CTW]

It's been a little while since I've looked at section 9, and I may not have been completely accurate in my first post.

The local web yielding and web crippling will apply if there is a concentrated force applied to the top flange of the beam or when the beam bottom flange is bearing on another surface.

The sketch I recall having comes from Salmon and Johnson. I've attached the applicable pages.

 

[a2mfk]

CTW- couldn't get that to open, but you've done so much, don't sweat it.

Thanks guys, I followed along with all the other checks, but I was thinking maybe that only applied to a bearing connection or a concentrated load condition.