Typical Moment Connection 2

[GDinMT]

Hey everyone, just wondering if anyone has some thoughts/insight as to what type of moment connections are being commonly used in practice. I know a lot of it depends on seismic design considerations, fabrication cost, ease of erection, ect. I am just looking to get a feel for what people are using in their designs.

Thanks,
GD

 

[KootK]

In order of economy, I'll use the following if it works:

1) Extended end plate moment connection.
2) All bolted flange/web plate moment connection.
3) Welded flange/web plate moment connection.

In all cases, I'll avoid having column continuity plates if possible. I may even up the column size to make it possible.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Guastavino]

"Sideplate" is a proprietary system in the US that is gaining traction. Seems economical for BIG jobs. Also, they do the design and charge the fabricator. Thus, you save on the design side, albeit you have to have a comfort level with their engineers, etc. It's kind of a dual effort. I haven't worked with them, but thought I'd give you an "outside the box" answer since KootK is in the thread already. Trust KootK, he's a legend here...

 

[BadgerPE]

I think if you talk with engineers across the country or globe, you will get very different answers. Although, I agree with KootK on his list, I have found that contractors in my area prefer an all bolted or bolted/welded connection vs. extended end plates. This is because end plates can be more challenging to field erect if not enough tolerances have been left.

My best advice is to call one or several fabricators in your area or area of a particular project. There is a lot of value in talking with them ahead of designing your connections.

 

[KootK]

This is because end plates can be more challenging to field erect if not enough tolerances have been left.

Can you elaborate on this? I've mostly only used them for small scale stuff where, I've assumed, the columns could be drawn together or pushed apart. I'm not sure what mechanisms would provide for tolerances in larger scaled applications. Fab short and shim?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[BadgerPE]

I have used them as well for small applications with only a few framelines. However, during preliminary design of a 3 story hospital addition, the contractor requested bolted web/welded flange connections for constructability in lieu of extended end plates. It sounded like they had an issue in the past where the beams came in right at dimension, but the columns were slightly off. So they had to have the beam refabricated to allow the columns to remain vertical. He said that if the same would have happened with a welded flange, they would have been able to grind the flanges back a little bit. Since the web bolt holes were slotted in the hz direction, it would have been a faster, cheaper field fix. This company sets a lot of structural steel so I have filed this little piece of information in the back of my brain for future use. Of course, this all goes away if the steel is set to plan.

 

[KootK]

Thanks for that Badger. I can see how it could be a problem. If you really wanted to use extended end plate, I'd almost think that you'd need to design with 3/4" shims from the get go. Otherwise, you've got no way to deal with beams that are too long or columns that are too close together. I could also see it being a bit problematic to fish the beams into place unless top of beam is also top of column.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[BUGGAR]

We always specify shims on our extended end plates. Sometimes they are used, sometimes not. We detail them out for full bearing but leave thickness up to contractor to match his means and methods. The contractors here in SoCal seem to expect them.

 

[GDinMT]

Thanks KootK, njlutzwe, BadgerPE, and BUGGAR. I appreciate the feedback.

-GD

 

[sandman21]

Sideplate saves alittle on the design side, not as much as you would think. Since they charge the contractor, treat them like a contractor, they are not an agent of the owner