Eaves Connection Detail in Steel Portal Frame 1

[Deener]

Hi All,
Currently exploring different options with the architect for the eaves connections in an exposed steel portal frame. The roof angle is relatively high (about 33 degrees to the horizontal) so the roof angle needs to be followed all the way to the far flange of the column (as opposed to having a flat top at the column). In the image below I show the two preferred options from the architect.
In option 1, there has been discussion of the bolt in peak tension being relatively close to the end of the beam. I don't see this being an issue from a strength perspective, only a bolt access perspective. The fabricator also prefers option 1 since there are fewer cuts to the beam end. My only qualm with option 1 is that it requires a stiffener due to the relatively thin flange. From a strength perspective, can anyone come up with arguments for one option over the other? Would you agree that the gravity load of the beam will be adding an unwanted lateral component to the column in Option 1 since the connection plate is not level?

Thank you in advance

 

[phamENG]

I'd go for option 3:

 

[IceNine]

I don't think option 1 adds a lateral component to the column design...you'd just have to include the component of gravity load parallel to the cap plate to the design of the bolts.

 

[Deener]

Thanks PhamENG. Unfortunately there's an HSS tie beam connecting each portal frame at that point. See highlighted member below:

 

[Deener]

Thanks IceNine. That's a great point about additional shear on the bolts.

 

[hokie66]

My preference is to fabricate part of the rafter with the column, moving the bolted connection up the rafter a ways, to where the bending is reduced.

 

[jayrod12]

I second hokie's suggestion. Move the splice around the corner, even if you had it such that the inside column flange projected all the way up to the top of rafter and you had a slope cut on the end of the rafter.

 

[Deener]

Thanks Hokie and Jayrod. I love that idea. Get that connection closer to the inflection point. Unfortunately the architect has shut that idea down since they are concerned the splice is much more visible in that case. Sigh.

 

[phamENG]

Have them field weld it per AESS specs. The architect can't complain then (apart from cost, but who cares about that anyway?).

 

[hokie66]

Your architect doesn’t appreciate a beautiful connection when he sees it. Architecturally exposed structural steel should have some interesting connections, not just bare sticks. But what would I know? I’m just a structural engineer, not somebody who knows it all.

 

[jayrod12]

It's exposed structure, what are they wanting to see? Connections are far more elegant than just the plain members.