cold formed/wood Shear wall on 4' canti. floor

That sounds about right. Some additional stuff that you probably considered even if you didn't mention it explicitly:

1) The load paths between the chords of the upper shear walls and the chords of the lower shear walls probably get designed for over strength or something like it depending on your local codes. Particularly so for uplift.

2) The sheathing over the cantilever is a transfer diaphragm and needs to be designed as such with respect to its shear capacity, boundary elements etc.

3) This arrangement will reduce the effective stiffness of the upper shear walls as the chords will effectively be sitting on springs at the cantilevers.

OP said:

What if we have an opening in the 2nd floor cold formed shear wall? we now have to have doubled joists/beams to restrain the chord forces near the openings?

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Yes potentially. Wherever you've assumed there to be shear wall chords in your upper shear wall design, there will need to be some kind of supporting structure below.

KootK said:

3) This arrangement will reduce the effective stiffness of the upper shear walls as the chords will effectively be sitting on springs at the cantilevers.

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100% agree that this is the right way to design the wall and deflection or drift. But does anyone here actually do it in your daily practice. I like to do it but honestly with all crazy design with discontinued shear walls everywhere, I don't have a system to do this effectively fast & proper enough especially for rigid or semi-rigid diaphragm assumption where force distribution depends on the effective stiffness of the walls. I just design all the walls without considering the deflection of the supporting beams and design those beams for Omega and keep deflection of those beams due to seismic within a range I think it's ok (either L/180 or L/240). On top of that, the deformation of the cantilevered diaphragm plays a great deal in the wall effective stiffness too.

Any better practice in this regard?

hotmailbox said:

But does anyone here actually do it in your daily practice.

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1) I didn't want to be a Debbie downer with respect to OP's proposal but I try pretty hard not to do this precisely because it's a pain in the butt for evaluation.

2) Evaluating this isn't sooo bad with the help of a simple 3D model. Sometimes I'll do that to get an equivalent, rigid body rotation of the the wall above and then feed that back into my normal calcs for drift. It does slow down what is normally a fairly automated process for me however.

3) I'm sure that you're right in that many disregard this aspect. I might myself for a 1' offset but probably not a 4' offset. Similarly, I do consider transfer beam flexibility where the beam is appreciably longer than the shear wall it supports. No judgement from me though, we all make compromises along the way, picking our battles as we go.

Thanks for the input guys! It helped a considerable amount!

With regards to opening on 2nd floor, depending on the nature of your building, I’ve seen a “perforated shear wall” approach for smaller buildings discussed by AWC. You can treat walls with opening as one large wall, and take a further reduction to the shear capacity on remaining solid shear wall.