Residential- Curved Stud Walls

[KSalem]

We will providing full structural design for a house with curved exterior wood stud walls. The intent is that the exterior walls will be bearing walls and shear walls. A couple of questions...

1. Minimum curve radius that you can practically sheath without any special processing of the plywood/osb?
2. Can you still use APA Braced Wall Panels for the lateral system, or would this fall outside of APA provisions?
3. If BWPs do not apply, does anyone have resources for the design of curved wood shear walls?


Thank you

 

[phamENG]

1. 0". Plywood is meant to be flat. If your plywood is thicker than 1/8" and curved any more than dead flat, it will need to be kerfed to get it to 'fold'.
2. I'm guessing you mean IRC Braced Walls? No. Those are for standard construction only. Curved walls wouldn't count.
3. No. Shear wall capacities in the code (SDPWS) are based on tested assemblies, so you really can't vary them without taking a lot on yourself as you're well outside of standard practice. There may be some paper out there that has explored the idea, but I'm not aware of any "accepted" or "consensus" approaches.

 

[ChorasDen]

What is the curve radius? I agree with Pham's comments, but if the radius is large enough, you may be able to get away with avoiding kerfing. I would be concerned with kerfing due to unbraced lengths of the studs, full wall width blocking at 12" intervals would be required if you go that route.

I would suggest considering installing the panels with the strength axis horizontal, and probably consider 4x_ at panel edges to provide a more robust nailing surface. What are the lateral demands on the wall? I'm not alone here on this, that I really don't like the usage of Thermoply sheathing for lateral resistance, but if the in-plane shear is quite low, maybe you can sleep at night with using thermoply, as it may be more bendable?

 

[DanKile]

They do make bendable plywood (one example). I don't know if it would work for this application. I have only seen its use vicariously.

 

[Brad805]

The bendable plywood is for cabinet makers or finishers. I have used this, and it is not structural.

 

[DanKile]

I have seen it used on a roof of a porch, because the "slope" was curved.

 

[Craig_H]

Quoting from your website: "bending plywood, is normally made out of hardwood imported veneers with the layers all running in one direction". It would therefore not be considered a wood structural panel.

I also imagine that a curved exterior shear wall would exert all manner of odd diaphragm forces into a diaphragm that, I hazard to guess, may also have a curved chord? Yuck.

 

[Ron247]

Just want to clarify which direction the wall is curved. Curved vertically, or in plan view?

 

[MintJulep]

Curved structural insulated panels are apparently a thing.

High Performance Curved SIP House Ennis MT

10" and 12" SIP walls and 12" SIP roofHERS Index 22Curved SIPs0.17 ACH50Off the grid: 4kW solar system and three 1kW wind turbinesICF basementRadiant heating with wood-fired boiler

www.sips.org

 

[XR250]

Two layers of 1/4" glued together I have seen work. if the demand was not that high - say like 100 PLF, I don't know if I would worry about shear.

 

[KSalem]

Just want to clarify which direction the wall is curved. Curved vertically, or in plan view?

Good question. The wall is curved in plan view, so the house is shaped like a yurt.

 

[phamENG]

This architectural form is common around the world, and is often built from wood. So it can work. But it's not going to behave the same way as our typical, orthogonal structures. So, to prove that it will meet building code reliability standards, you're going to need to approach this differently.

That approach will depend on scale and other architectural details.