Hi,
I have some questions regarding Fx (ELF procedure) and Fpx (diaphragm forces) when calculating diaphragm shear as well as collector/chord forces (while throwing in an offset shear wall from above to cause a horizontal irregularity type 4). Note that this is light-frame wood construction. I'm using the ASCE 7-22 as reference.
The attached document has all the information. Red = basically how I've been calculating everything. Blue are my questions.
Basically, it comes down to:
1. When checking diaphragm shear, collector forces, or chord forces (whether using diaphragm (Fpx) forces OR ELF (Fx) forces), I should also include the horizontal ELF load from the offset shear wall above where it occurs. My question is if Omega=2.5 should be factored in that offset shear wall force? Section 12.3.3.4 seems to be about the couple force from the offset shear wall above instead of the horizontal load AND section 12.10.1.1 (which does talk about the horizontal load w/ Omega) has an exception for Omega=1.0 for light-frame construction. Therefore, I think Omega=1.0
2. The follow-up to question #1 would be what Rho should be applied to the force from the offset shear wall above. If designing any of the 3 items mentioned in question #1 using ELF (Fx) forces, then Rho=1.3. If using diaphragm (Fpx) forces, then Rho=1.0 (based on item #7 from section 12.3.4.1)?
3. For the 25% diaphragm force increase per section 12.3.3.5 where an offset shear wall above occurs, it seems like that is not for checking diaphragm shear but only the connection between diaphragm to collectors/shear walls and collectors to shear walls?
4. I didn't mention this explicitly in the document, but I assume I still need to use Fx forces when checking the chords of a diaphragm?
Edit: I think I named the PDF weird so if you download it, you will need to name it something like "sketch.PDF". The ".PDF" would be needed
Thanks,
I have some questions regarding Fx (ELF procedure) and Fpx (diaphragm forces) when calculating diaphragm shear as well as collector/chord forces (while throwing in an offset shear wall from above to cause a horizontal irregularity type 4). Note that this is light-frame wood construction. I'm using the ASCE 7-22 as reference.
The attached document has all the information. Red = basically how I've been calculating everything. Blue are my questions.
Basically, it comes down to:
1. When checking diaphragm shear, collector forces, or chord forces (whether using diaphragm (Fpx) forces OR ELF (Fx) forces), I should also include the horizontal ELF load from the offset shear wall above where it occurs. My question is if Omega=2.5 should be factored in that offset shear wall force? Section 12.3.3.4 seems to be about the couple force from the offset shear wall above instead of the horizontal load AND section 12.10.1.1 (which does talk about the horizontal load w/ Omega) has an exception for Omega=1.0 for light-frame construction. Therefore, I think Omega=1.0
2. The follow-up to question #1 would be what Rho should be applied to the force from the offset shear wall above. If designing any of the 3 items mentioned in question #1 using ELF (Fx) forces, then Rho=1.3. If using diaphragm (Fpx) forces, then Rho=1.0 (based on item #7 from section 12.3.4.1)?
3. For the 25% diaphragm force increase per section 12.3.3.5 where an offset shear wall above occurs, it seems like that is not for checking diaphragm shear but only the connection between diaphragm to collectors/shear walls and collectors to shear walls?
4. I didn't mention this explicitly in the document, but I assume I still need to use Fx forces when checking the chords of a diaphragm?
Edit: I think I named the PDF weird so if you download it, you will need to name it something like "sketch.PDF". The ".PDF" would be needed
Thanks,
