Frame Placement

[JStructsteel]

Got a 25'x50' existing building connected to a 3 story. Architect is opening up space between, so it will become a stand alone building. Old brick building, with wood beam and plank decking. At the end they are separating the two buildings, was going to add a moment frame for stability. Would not be a huge load.

Looking at the picture where would you place it. As I show it, I was thinking under the last beam, and connect to that. More I think about it, would be better just beyond the last beam, and connect the deck to it. I was thinking connect a wood 2x on top of the beam, and then put tight to the deck. Contractor than can fasten the deck to that. Other option was leave it short a few inches, and then field weld an angle along the slope of the roof, again fastening the angle to the deck.

Any pros/ cons to these ideas?

 

[KootK]

I think that it would be easier, and more convincing, to attach your frame to a timber beam rather than directly to the deck. Making new, underside deck attachments in a sagged roof without mucking up the roofing can be difficult. With your frame attached to a timber beam beam, you can just attach at a few, discrete points and use the deck nailing to the existing beam to deal with that part of the load path. I like the steel beam directly below the existing wood beam if there's headroom available for it. If not, you might consider something like what I've shown below.

 

[JStructsteel]

Thanks KootK.

I like the beam under the existing too, what I was thinking is leave a small gap, and have plates each side to thru bolt or structural screws. Ill upload my detail when complete.

 

[JStructsteel]

Here is the detail I was going to use

 

[XR250]

Perhaps add some blocking as it appears unstable. Also, why the stainless bolts?

 

[JStructsteel]

Thanks, good point. This is exterior, Was going to either use stainless hardware and galv steel. need to talk to architect about that.

 

[KootK]

I kinda like this, especially if you could snug it up before locking up the anchor bolts. I'm thinking lags but you'd need to verify that some are available that would be smooth shank all the way through the HSS. Galvanized with some weep holes if it's exposed to the elements.