Wood shear wall. Sheathing on both sides.
Wood shear wall. Sheathing on both sides.
(OP)
I am reviewing a prototypical building/calcs for a large chain restaurant. Prototype works in most of the country, but now it's a Seismic Design Category D. In one direction of the building I only have two 4' width of shear walls for the whole direction of the building.
Question: if you place shear rated panels on both sides of a shear wall, can you effectively divide your calculated shear wall deflection in half? I am using NDS procedure for calculating deflections.
FYI, shear flow is around 900 plf to each wall. Wall height is 14'.
Thanks for the help.
Question: if you place shear rated panels on both sides of a shear wall, can you effectively divide your calculated shear wall deflection in half? I am using NDS procedure for calculating deflections.
FYI, shear flow is around 900 plf to each wall. Wall height is 14'.
Thanks for the help.






RE: Wood shear wall. Sheathing on both sides.
RE: Wood shear wall. Sheathing on both sides.
I'd have to look at the IBC shearwall deflection equation to see where that comes into play.
RE: Wood shear wall. Sheathing on both sides.
The prototypical calcs did not include a deflection calc for the shearwall... which I thought was pretty lazy (or just a mistake, we all make them).
After sleeping on it, a 4' shearwall is just making me nervous for these loads. I can't see it being stiff enough for this tall of a wall and this particular location. S1=.30, Ss=1.25. I'll just have to talk to the architect and figure something else out.
RE: Wood shear wall. Sheathing on both sides.
With wood shearwalls - your R = 6 1/2 +/-. You still might be OK - just might have to use one heavy nailed shearwall system and some high strength hold downs.
RE: Wood shear wall. Sheathing on both sides.
RE: Wood shear wall. Sheathing on both sides.
Used this trick many times.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Wood shear wall. Sheathing on both sides.
That is a great "trick!" I have never heard of that one before, but I really like it.
RE: Wood shear wall. Sheathing on both sides.
I don't think that you can divide the calculated deflection by 2 for sheathing on two sides of the shearwall. The deflection equation in the IBC & NDS has 4 components: bending, shear, nail slip & anchorage slip. Maybe you can change the results of one of the components but probably not the total deflection.
You might also remember that the shear value in the components is the Strength level seismic shear (not 0.7E).
Since the shearwall aspect level is greater than 2:1 (14/4=3.5) for seismic loads the unit shear capacity from the capacity tables should be multiplied by 2b/h.
RE: Wood shear wall. Sheathing on both sides.