End plate moment connection-column to beam connection

[Veer007]

Hey guys, if we provide continuous bolts from top to bottom for an End plate, will it take moment force? or need to separate individual bolt groups both top&bott as i need to satisfy also a shear force. snap attached

Thanks in advance!!

 

[skeletron]

I think AISC DG 4 and 16 handle this.

The tension-compression couple creating the moment is through the flanges. I take the moment out in the 4 bolts (one row above, one row below) centered on the flange. The remaining 3 rows of bolts I would count on strictly for shear.

 

[Tomfh]

It will carry moment and shear. I use similar logic to skeletron.


If you use a sufficiently thick end plate you can often omit the stiffeners.

 

[WinelandV]

Don't forget to do the column capacity checks (DG 4, I believe).

 

[DrZoidberWoop]

Connection design engineer for a steel fabricator here. When a situation like this comes up, we draw a section cut looking at the end-plate and make notes to the EOR/detailer designating the first or second rows of bolts nearest the beam flanges as "Moment Resisting" and the interior bolts as "Shear Resisting". Something like what's attached.

 

[chucklesNOLA]

There are a lot of ways to idealize this connection for resisting various member/connection demands (shear in 2-axes, axial load, flexure in 2-axes, torsion). I generally look at the "load sharing" among the bolts in the group based on satisfying compatibility. For example, the outermost two lines of bolts in your connection are most likely to resist both the strong-axis flexure (causes tension in bolts) and any torsional load (causes shear in bolts) due to their distance from the NA/center of rotation in each case. They probably also take a portion of the strong- and weak-axis shear (causes bolt shear) and weak-axis flexure (causes bolt tension). Similarly, the "web" bolts are likely to be resisting weak-axis flexure (bolt tension) and strong- and weak-axis shear (bolt shear). Depending on the stiffness of the plate, there could be an even or uneven distribution of any axial load between the bolts closest to the flanges and the bolts closest to the web.

I've seen what DrZoidberWoop mentioned regarding designation of specific bolts to resist specific types of loads. I recognize that this is both common and seems to have stood up to real-world loading conditions for a while. It's also a lot easier to design and review than having combined stresses on all of the bolts. It's just not the way I like to do it.

 

[Tomfh]

Chuckles,

Yes in reality the top bolts will cop the brunt of the tension, and will likely carry a lot of shear.

It’s something I wonder about. Are some of the bolts getting more than their assumed share of the load and if so do they have sufficient ductility to hold on until the other bolts join in?


There are limits on moment and shear interaction when designing beam sections. If the sections are working hard you can’t just allocate all the moment to flanges and all the load to web. But we seem to do this with bolted connections?

I suspect it all comes out in the wash, but I don’t know for sure!

 

[JoshPlumSE]

Tomfh -

There was a good amount of testing of these types of connections at Virginia Tech. That testing was the basis of AISC's two design guides on the subject. You might want to review the literature cited in those design guides if you are concerned about the assumptions made in these procedures.

 

[Tomfh]

Thanks joshplum.

I will have a look at those.

 

[chucklesNOLA]

There was a good amount of testing of these types of connections at Virginia Tech.

One good test is worth a thousand expert opinions...or something like that.

 

[Veer007]

I will count on top and bottom four bolts which near from flanges for moment and rest for shear, i thought each bolt where not in shear, all those has shear+tension & shear+compression,

but theoretically i will count on by mentioned above..let me know your concern on this

Thanks in advance!!