Simpson Strong-Wall

[medeek]

Whats your opinion of using Simpson Strong Walls in lieu of portal frames/shear walls? What other/better options are out there?

I've got a 12'x14' garage door with only 24" of wall on both sides (single story), Wind Speed (ult.) 155 mph, Seismic Cat. D. The stud wall height is approx. 15' with a 6" stem wall above grade, my aspect ratio is about 7.5 which definitely won't work for any sort of standard shearwall and the wall height exceeds the max. height allowed for portal frame details in both the IBC (10' max height for figure 2308.9.3.2) and IRC (12' max wall height with pony wall above header Fig. R602.10.6.2). To make this work I think I will need either a Simpson Strong-Wall or a much more expensive Simpson Strong Frame or equivalent.

 

[msquared48]

Extend your concrete stem wall below the shear wall so the shear wall is no more than seven feet high, or make the shear wall all concrete.

Mike McCann, PE, SE (WA)

 

[KootK]

Strong wall is probably the way to go. You could also have a truss fabricator make you something similar.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[medeek]

I'm wondering if I take the standard portal frame in the IBC/IRC and sheath both sides (double shear wall) and then upgrade the nail spacing as necessary maybe I can design my own portal frame that I can rationally make work. The key to the portal frame design is making the haunch strong enough to resist the moment at the beam and shearwall connection.

 

[RFreund]

I've always been tempted to try and design a narrow shearwall constructed like a built-up cantilevered beam using studs as your top and bottom flange with the plywood on both sides. Design the fasteners for VQ/I kinda thing. However I usually just go with the simpson shear wall.

EIT

http://www.HowToEngineer.com

 

[jayrod12]

RFreund, isn't that just a plywood box beam?

 

[KootK]

I feel the DIY pull with this too. I'm pretty sure that I could handle the strength side of things. It's stiffness that holds me up. The testing that comes with the Simpson walls feels good.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[manstrom]

I have never seen a strong wall installed properly.

They tend to forget to install the 24" deep 1" anchor bolts, then they ask for a repair.

 

[RFreund]

@jayrod -> I think it deserves a fancier name but yeah, yeah, I guess you're right.

The testing that comes with the Simpson walls feels good.

Ha, yeah, true. Sometimes I enjoy it and sometimes I feel like they Stong-arm me into using their products.

EIT

http://www.HowToEngineer.com

 

[hokie66]

I wouldn't rely on wood, with the problem of fixing the bottom. Reinforced concrete or reinforced masonry would be my choice.

 

[medeek]

After doing some more reading and research I thought I might give the DIY approach a try. I normally don't like to put my "real work" out for review in a public forum but since this is pretty much non-standard and I am in uncharted territory on this one a little bit of peer review definitely can't be bad. My analysis is at the link below:

[URL unfurl="true"]http://design.medeek.com/images/misc/2014-017_PORTAL_FRAME_ANALYSIS.pdf[/url]

I essentially have two garage door portal frames next to each other but out of plane sharing a 8138 lbs shear load. The biggest jump I made in my opinion was dividing the shear forces not equally but based on the aspect ratio of each portal frames shear panels.

The smaller garage door 10x8 has an shear panel aspect ratio of 4. => 64.3% of load
The larger garage door 12x14 has a shear panel aspect ratio of 7.4. => 35.7% of load

The other big assumption made is that the holdown and tension strap at header interface counteract the uplift force equally. My gut tells me that the tension strap will actually take more load than the holdown but I can't prove that, hence I have given it a little extra capacity.

The paper located here was helpful in my thinking the loads through:

Portal Frame WCTE 2012

 

[jguer005]

Something to think about, and maybe you already have, but with the Strongwall application, do you actually have 24" of clear wall space to put the panel in to? Sometimes corner studs and king studs limit the space you have and you might only be able to use an 18" wide panel which limits your choices for the 15' height you mentioned.

Just a thought.