Horizontal 2x6 T&G as Shearwall Sheathing

[EngDM]

Is it possible to use 2x6 oriented horizontally as your shearwall sheathing? There are tables in O86 for diagonal member paneling, but I couldn't find anything for horizontal. My gut is saying no, because there is no shear transfer between adjacent horizontal members. With diagonal members, at least the member can go into tension/compression and drag the base shear from the top chord to the bottom chord.

So aside from some sort of shear transfer detail between adjacent 2x6 panels I don't think this works.

Just looking for a sanity check or some insight.

 

[Greenalleycat]

@skeletron your message got me interested so I went into our seismic assessment guidance
The relevant table is below - horizontal board sheathing is estimated at a mere 1.0kN/m
This is particularly low as:
a) these are tested values in the context of typical houses (2.4m studs) so not applicable to 21' studs
b) these are 'probable' values based on testing i.e. they are less conservative than design values, you'd have to reduce them down if using them for design somehow

 

[EngDM]

Although not something I would hang my hat on, Table A-3 of the NRC's publication of "Seismic Evaluation of Existing Buildings" provides a 4.4 kN/m (301 lb/ft) strength value for "floors with straight T&G sheathing" or "roofs with straight sheathing and roofing applied directly to the sheathing".

Interesting. I wonder if they are relying on the roofing that is applied directly to the sheathing to transfer some of that shear between members.

 

[Celt83]

just to clarify something your "stud" walls are they 21 ft tall with studs spaced around 4-5 ft on center?

if the answer is yes then you don't have "stud" walls you have posts and beams and would recommend looking at different systems for lateral resistance.

 

[Greenalleycat]

Just found the flooring table too - our values are similar to those from Skeletron
Interesting that there is such a difference for roofs vs walls - the hold-down forces must be a big influence on the available capacity

 

[EngDM]

just to clarify something your "stud" walls are they 21 ft tall with studs spaced around 4-5 ft on center?

if the answer is yes then you don't have "stud" walls you have posts and beams and would recommend looking at different systems for lateral resistance.

Correct, but the intermediate posts are not load bearing just to clarify. The posts @ 30' are the bearing ones.

 

[Tomfh]

Interesting that there is such a difference for roofs vs walls

The sheathing and roofing material perhaps?

But in that case, why is flooring also much higher.

Regarding the weatherboard, 0.3kN/m seems quite low. Whats so bad about weatherboard compared to other boards?

 

[Greenalleycat]

I think the materials would be very similar - I expect it's because the walls are cantilever model, the diaphragm is simply-supported
So chord forces are much lower and your weakest connection will be shear at the perimeter (diaphragm) vs tension hold-down (wall)

No idea re the weatherboards - I imagine it's the nails?
This is testing typical real-world construction which will probably have two shitty nails per boards holding it in
Also it's overlapping rather than direct fixed so the load path is a lot gnarlier