Alternate Braced wall panel (IBC 2006 2308.9.3.2)
Alternate Braced wall panel (IBC 2006 2308.9.3.2)
(OP)
My question is simple. I have engineered quite a few houses with 2'-0" wing walls on either side of the garage door. these garages almost always were 7'-0" tall doors, so my shear wall aspect ratio did not exceed 3.5:1. However, over the last couple of years, these homes are being built with 8'-0 tall garage doors, which exceeds 3.5:1 aspect ratio. IBC 2308.9.3.2 shows an alternate braced panel that would work great for these walls. However, I am in seismic design category 'D' and am skeptical this can be applied in my area since the braced wall panels table (IBC 2006 table 2308.9.3(1)) only goes up to seismic design category 'C'. Am I understanding this right? It just seems like I am the only one specifying strong walls at the front of the garages that don't meet the aspect ratio criteria. Although I don't think this is an option in my area, I would like others insight on when this detail could be utilized.






RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
It does apply if the wall is constructed from scrfatch in the field as a normal plywood shearwall.
You know, to get back into the aspect ratiuo limits though, all you have to do is raise the height of the concrete stem pall below the shear wall.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
You are correct, with the strong walls or shear braces being tested systems, the aspect ratio does not apply. I spec the strong walls when I have walls at the front of the garage that don't meet the aspect ratio. 99% of the time, the shear forces are well within the shear strength range of site built shear walls, the strong walls are ONLY specified to meet the aspect ratio. The taller concrete stem wall is also a good idea. I have mentioned this to contractors before and they act like I gave them an alternate option of building the foundation out of moon rock. I think the taller concrete stem wall seems really easy, but only a handful of contractors have wanted to do that. I do not have much experience in construction, so maybe there is a reason beyond what I can see why this extended stem wall is a problem. In the end I think I was hoping for a little "magic" or hidden exception in the code to save me the "we've been doing it this way for years" excuse for not reading the plans. Sigh.
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
Where are you?
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
RE: Alternate Braced wall panel (IBC 2006 2308.9.3.2)
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask