Wood Stud Spreadsheet

[tlen22]

I am updating and rewriting my firm's wood spreadsheets and I am currently on wall studs.

The spreadsheet is finished, I am just double checking it works and matches with other programs (ForteWeb, WoodBook, etc.) but I am running into some complications with the lateral loading.
The spreadsheet considers if you're an interior or exterior wall in order to apply the correct loadings.
I have inputs for wind and seismic forces (Ev and Eh) while these programs only consider wind laterally. I know when checking deflection, you only consider wind but when checking bending, would you consider the seismic force if it controls?
I know it is unlikely for the seismic force to control for the exterior wall example, but what about an interior wall?
I also have the spreadsheet set up for it to automatically use an OOP load of 5psf to check bending and deflection if the seismic force is less than 5 psf.

Thanks in advance!

 

[EngDM]

Seismic loads would typically be applied at top of stud since the load is from mass/inertia, and the mass typically sits on a diaphram of some sort, which in turn sits on your studs. Wind gets applied to the stud itself, whether in UDL or point load (however you want to consider it). Perhaps you'd run the stud with an eccentricty of whatever the diaphram deflects? If it's not load bearing I doubt I'd worry about it since seismic is life safety and interior partitions cracking or deforming isn't a life safety issue.

I suppose a UDL from seismic could occur due to wall weight, but I'd imagine you'd need a pretty heavy wall assembly to govern over wind, even if wind is only 5psf(I could be wrong I'm in a low seismicity zone so maybe it would govern).

 

[driftLimiter]

The code says design for all the load combinations. It doesn't really seems like we have the option to just ignore seismic.

There can be scenarios where wall out of plane seismic creates the largest force effect. Some wall finishes are very heavy.

I don't see how just adding an Sds input, then checking out of plane seismic requirements while checking the stud bending is that hard. You've already got all the code setup now just need one more load combination.

 

[JAE]

If you are writing a spreadsheet for others to use then you should be careful to consider all possible stud wall scenarios and conditions - or put a large noticeable disclaimer on it.

For most "normal" stud walls with moderate spans and typical wall surface materials you are correct that wind controls.

But it could be that someone someday tries to use your spreadsheet to design a 25 ft. tall stud wall with 4 or more inches of veneer on each side. There might be some seismic issues with that.
Out of plane deflection might be critical for such a wall.

What EngDM is stating is that many stud walls serve as shear walls for supporting diaphragms. Some walls, (most walls?) do not act as shear walls and simply need to be self-competent partitions taking only perpendicular component load.

Also - don't forget that seismic also has a vertical component that must be considered - this affects shear walls and non-shear walls alike.

 

[tlen22]

Thank you all for responding and helping out.
I have seismic built into the system already and checks all ASD load cases.
I mainly was curious why other programs I've used in the past might have differed from this.
But it's reassuring to know I wasn't going crazy!