Woodworks Allowable Story Drift

[Supun93]

When i model a two storey building, one of shear lines exceed the allowable story drift value. There is a large opening in that shearline. Can anyone give me an guidance how to reduce the story drift on that shear line? If i add a Simpson strong wall, will that reduce the story drift on the site? How can i add that to the model in woodworks? Thanks

 

[phamENG]

Woodworks doesn't do proprietary shear walls, and I haven't found a way to simulate one.

How to reduce story drift? Stiffer walls, mostly. Tighter nailing patterns. Include sheathing on both sides of the wall. That sort of thing. If you want to include a strong wall (which doesn't do much for drift - they're tall and slender to provide strength where a site built wall would violate aspect ratio limitations), you'd have to do the line by hand. Easy to do, but a little time consuming if you're not accustomed to doing it.

 

[skeletron]

I always find that the hold down + nail elongation is about 67%-80% of the deflection value, so you can see if increasing the HD strength (therefore, decreasing the ultimate deflection linearly by the Tf/Tr ratio) works as well as using the fatter nails and tighter spacing. Depending on your A.R. you might be SOL.

I find that WoodWorks usually freaks out with big openings because the A.R. goes out the window. So potentially you could see if FTAO works in this case or go to a moment frame.

As for modelling the strong-wall, you can't really but you kind of need to fudge it a bit in order to get the right distribution. I would make sure the rest of your structure is doing ok, run the model with a nominal wall, measure the forces and deflections, then re-run the model with an ultra stiff wall, measure the force and deflections. Consider those two events as bounds, and then run the calcs with a force within those bounds applied to the WSW and do handcalcs on that.

 

[Supun93]

Thank you. This really helps.