Is this structure braced?

[bhiggins]

Hi everyone,

I'm currently working on a house with a third-story pop-up section that has an elongated oval shape. The ends of this structure will feature curved walls framed with curved plywood sheathing, which will be finished with a layer of corrugated metal cladding.

I'm a bit hesitant to rely solely on the curved plywood walls for lateral bracing, as curved plywood typically does not have a recognized NDS shear value. However, given that the corrugated metal cladding adds an additional structural layer, I believe the combined assembly might provide sufficient shear resistance.

Has anyone seen this approach justified before? Do you think this configuration can be considered braced, or is there a feasible way to justify this bracing scheme without needing to add additional frames or structural elements?

Appreciate any input or references that could support this.

 

[Michel60]

How tall is the pop-up? For a reality check would a wall at each end with an effective length of 3-4 feet get the job done?

For technical support (assuming you're in the US) you may want to reach out to the American Plywood Association (APA) (www.apawood.org). They may be able to direct you to some research on curved/sheathed walls.

 

[rb1957]

can you add ribs inside the shape ?

seems an odd thing to be doing ...

 

[Tomfh]

You’d need a proper diaphragm, something akin to a tank lid that genuinely locks the walls together. Otherwise the wall can just crumple at the sort spots. Sounds difficult using plywood and normal metal cladding.

 

[KootK]

I've done this before for some large, turret looking things. That said, I'd be seeking the following:

1) Convert the curved wall into straight segments that are, hopefully, long enough to be viable shear walls in their own right.

2) Think carefully about the hold down details at whatever thing the curved wall segments will be transferring to below. This can get ugly fast.

The last thing that you want on something like this is to have gone with a marginally cheaper solution only to get out on site and find that all of the shear wall connections are garbage because of some spatial issue that didn't occur to you during design.

Fundamentally, I don't like this at the aspect ratio of this thing. I feel as though some light duty moment frames would be a good choice here.