Distribution angle with metal stud walls and wood roof truss

[Ben29]

I am designing a 1-story building (church). We are using 16ft tall metal stud exterior walls. The wood roof trusses will be attic trusses that span ~ 40ft. This hybrid system of wood trusses + LG walls was dictated by the architect.

I checked the top plates and they do not work for the loading condition when the studs and trusses do not align. I don't want to specify studs at 24"o/c and tell them to align the trusses because I fear that the chances of them aligning are none and none-at-all.

I discovered that a distribution angle would work to distribute the load, but is this constructable? Would you use a thru-bolt to connect the wood plates to the angle and also to the LG top track?

I am providing double wood top plates for the hurricane anchor connection, but I guess I can reduce it to (1) plate and use a Simpson H3 tie, which only requires (1) top plate.

Is there a better way to distribute the load to the metal stud wall? After Christmas break, my brain is not firing on all cylinders quite yet.

 

[Celt83]

Would not do an angle as a load distribution member its shear center is on the inside face of the wall. If needed I’m used to seeing a small HSS distribution member.

Can you size a heavy gauge top track to deal with the reaction?

Most of the simpson clips have values into cold form studs, I’d avoid introducing additional wood plates and tie directly to the cold form that way avoid having to do extra load path detailing to get from the wood plates into the cold form.

At 16ft tall I’d expect studs at 12in o.c. so getting the trusses constructed aligned with the studs wouldn’t be an unreasonable request.

 

[Ben29]

Here is the version with the distribution tube. Will they have a problem fastening the hurricane tie to the 1/8" thick steel distribution tube?

 

[KootK]

CFSEI has a pretty good technote on this issue that might help to generate some ideas: Link

I'm sure that it's more onerous to fasten the hold downs to the HSS but, for a thin walled section, I suspect that it's possible.

 

[Celt83]

I believe some of the clips allow use of PAFs which should not have any issue with an 1/8” wall thickness. Simpson Cold-Formed Connector Catalog: Link

I would double check your 6” studs at 16”, at 16 ft tall load bearing and exterior I would anticipate medium/heavy gauge 8” studs or maybe heavy gauge back-to-back 6”. SSMA Tech Catalog is a good quick resource: Link

 

[Ben29]

@Celt83: Thanks for looking out.
I checked the stud wall a few times.
I am using the MarinoWare catalog. Using ASD loads. 15psf Lateral Load.
600S162-54 (50 ksi) yields an allowable axial load of 3030 #/stud when spaced at 16"o/c.
My actual loading condition is 1400 plf = 1867 #/stud based on studs at 16"o/c
The axial load I gave in my original post was too conservative.

 

[Ben29]

Kootk- thanks for the tech note. Very helpful. I was spinning my wheels on this detail. I will run some numbers to see if I can get the top track to work on its own.

 

[XR250]

Why not count on the dbl. wood plate as the distribution member? The uplift on the track will be an issue, but that should be easier to manage as you can specify the bolts being near the studs.

 

[Ben29]

I checked the double SPF top plates to take the load and they don't work.
I would like to use a double LSL 1.3E 1.5" X 5.5" plate. That will work all day long. I hope they are OK with that.

 

[XR250]

For a simple building, asking the studs and the trussesI checked the top plates and they do not work for the loading condition when the studs and trusses do not align. I don't want to specify studs at 24"o/c and tell them to align the trusses because I fear that the chances of them aligning are none and none-at-all.

I think is building is simple, you should not have an issue with things lining up. Most framers are pretty good with layout in my experience.
That would bring you back to SPF or even light gage top plates if the LSL is an issue

 

[dik]

Would it not be easier to align the trusses with the studs? Also at 24"o/c, it's slightly better for energy efficiency, specially for CFS construction.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[spaseur]

We have designed many CFS stud structures. We specify that the studs align with the trusses. We have found that the contractor had rather add a full height stud than use any king of distribution member on top of the wall. Using a wood distribution member may violate the fire ratings for the exterior wall. Need to check with your architect to make sure it will be allowed. Or it may have to be fire-retardant treated. We generally specify a small tolerance for alignment of the truss with the stud. If the stud and truss are out of tolerance the contractor has to add additional studs to support the truss. Just my 2 cents.