Opening Near End Of Shear Wall 2

[BadgerPE]

Hey all,
What is the best way to handle a short wall segment at the end of a shear wall that does not meet aspect ratio requirments? I feel that in the attached example, two options are present:

1) Ignore the 1.5' wall segment and window and design the remaing wall as a perforated shear wall.

2) Use the two wall segments on either side of the door to design the wall as segmented. If it is segmented, what transfers the lateral load across the window opening to the first segment? Top chord? Header?

If either of these two options are viable, would it be best to still place a hold down at the outside of the 1.5' segment or are they only necessary on the segments of wall designated as shear carrying segments?
Thanks much!

 

[OHIOMatt]

I would ignore the 1.5' segment so there would be no reason to use a hold down. I would check to see if the other two segements could handle the shear. Since they are different lengths, you will need to look at the relative rigidity of the segemnts. If you find they don't work (in my opinion, unlikely give what I see) then I would look at a perforated shear wall design.

I would place boundary nailing from the top portion of the wall to the top plate. The top plate would be designed as a collector to distrubtute forces to the shear wall segments. This means that you would need to have to stagger the members or use something like a Simpson CS strap (or larger if the forces require) to ensure continuity.

 

[BadgerPE]

Thanks for the quick response Matt. I should have noted that the shear wall is only about 9' tall and there is a gable end truss directly over it. There is not a second wall on top of it like currently detailed.

 

[OHIOMatt]

The gable end wall section will still need to act as a shear wall. It is the connection from the roof diaphragm to the shear wall.

With that said, I think that (1) row of boundary nailing at the top plate and (1) row of boundary nailing at the top of the gable end would be required.

Keep in mind, that the boundary nailing at the top of the gable will be less than that of the shear wall segments due to it being continuos.

 

[cetiger]

I agree with OHIOMatt. If you find out you do need the wall (assuming new construction), you can specfiy a pre-manufactured shear wall panel such as a wood strong-wall or steel strong-wall manufactured by Simpson Strong-Tie. The panels come in widths from 12" to 24" and resist a pretty good amount of lateral loading. They also meet R=6.5 (for seismic calcs) which is identical to Light Framing w/ Wood Shear Panels, as I'm assuming is your structure type here.

 

[woodman88]

You should be careful using difference lengths of shear walls. If your main shearwall drift is a 0.125” and the maximum drift for the Strongwall is 0.25” than you can only use 0.125/.25 times the maximum allowable shear of the Strongwall for shear.

Garth Dreger PE
AZ Phoenix area

 

[msquared48]

I would use the two longer walls to either side of the door opening and forget the 1.5' portion. Looks like the difference in shear would be only around 10% or so without the wall.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

And as OHIOMatt stated, the wall double top plate, if properly nailed and spliced, can more than adequately serve as a drag collector and distributor to the shearwalls.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[dkite007]

I agree with Matt, though I don't know why you would need to look at relative regidity? These are light-framed timber shearwalls, right?

I wouldn't check relative regidity.

 

[OHIOMatt]

Since the shear walls are conected by the top plate it essentially acts as a strut between them. They will have to deflect the same. A longer wall is stiffer regardless of the construction. IMHO this is really the only way to calculate the actuall forces in each wall.

 

[rscassar]

The loads can be distributed to a series of wood shear walls based upon only the length of each wall when the same plywood and nailing for walls of equal height.

From your diagram, it appears that one wall is 7-1/2' and the other wall is 6' in length. So should the loads be distributed to the walls by proportionally (55% and 45%).

There is an example in the seismic design handbook.