Gable End Shear Wall / slopped diaphragm 1

[RFreund]

I have a couple questions regarding gable end shear walls with a pitched roof stemming from a recent project which I believe will need to be handled with steel. There are 2 situations and they may in fact be one in the same.

1. No ceiling diaphragm (i.e. vaulted ceiling - ridge beam or scissor truss) thus requiring full height studs to underside of roof diaphragm.
2. Ceiling diaphragm (flat ceiling) with wall studs, top plate then gable studs atop the top plate.

With either of these situations I'm trying to visualize the load path.

Basically my question is: Is the entire gable wall a shear wall? In case 1 there would be one full height shear wall. In case 2 there would be an upper triangular shear wall and a lower shear wall? Are openings in the upper triangular shear wall treated the same as for a rectangular shear wall? Or could you argue that the triangular shear wall is not needed and 2 point loads at the bearing ends of the gable truss/rafter transfer the shear of your diaphragm into the lower rectangular diaphragm.

See Attached.

EIT

 

[msquared48]

Sorry for the belated answer. I went out to a skating and pizza party with the grandkids. To answer your question...

No. There is the area of wall betweeen the two long vertical wind column s that can be developed into a shear wall, probably perforated, in this area.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[RFreund]

yummmmm piazzaaaa, sounds like a good time.
I see now, so there has to be a shear wall in the triangular portion of the wall. This may be a problem because I realized my sketch does not have the windows laid out exactly as the architect has them. In his scheme the triangular portion is basically all windows (the middle window I have shown is larger). They were hoping to use wood but I think they will need to change the window layout because currently I have no space for a shear wall in the triangular portion. Unless there is another solution? My boss recommended to use a steel frame (which is most likely what we will end up doing) but it would be great to be able to propose another solution.
Thanks again.

EIT