Designing a two sided sunroom

[B-SE]

Hello all,

Any insight and advice is most appreciated. I've been charged with designing a sunroom that will be attached to a 1900's unreinforced masonry wall residence on two sides. The short side is 18' and the long side is 36'. The long side is essentially 3 12 ft windows with 6" jambs.
The short side has a centered brick chimney.
The existing structure can't take any lateral connections.
Am I relegated to steel posts in the jambs connected to LVL's to develop lateral stability?
Column to beam moment connections?

Thanks in advance

 

[phamENG]

1) Why can't the existing structure take lateral connections? I've designed connections to plain clay brick walls from the 1900s, 1800s, and even a couple from the 1700s. I only bring this up because lots of people see un-reinforced brick and immediately assume it has no structural value. If that's not you and there's another reason, sorry for jumping to the conclusion.

2) You're in TN, so the wind loads aren't all that bad. Check out the Simpson Moment Post bases.

3) If this really has to be a fully independent structure with minimal vertical support and no braces allowed, then yeah - you're kinda stuck if the MPBZ's don't do it. I wouldn't attempt to make a moment connection between a wood column and beam, or a steel column and wood beam. For a decorative overhang? Sure. For the primary stability of a 600sf living space? No.

 

[hokie66]

3-12' windows with 6" jambs between? Yes, that sounds like it won't take much lateral loading. Make the new structure stand on its own.

 

[Skinnattittar]

Are the windows from floor to ceiling? If not, the wall below can be used as a shear wall. The jab posts will probably have to be more substantial than just some 2x. Extend the posts from bottom to top and design them as fixed at the top of the short wall (bottom of the windows) then put that lateral load into the top of the short wall. Make sure to add tension ties between the wall sections, across the break caused by the posts.

At the existing building, yeah, why can't you use the existing building for lateral resistance? If it is a concern, I would design the building as above, as a three sided structure. I normally would not do this for anything other than what we call "salt sheds", where torsion and deflection aren't a big concern because there are not delicate elements (doors, windows, finishes, etc..). But if you can pin the building to the existing, the "twist" should be taken care of, but you're going to design the new building to deal with the forces on its own and to limit deflection as much as possible.