Braced wall panel over a large opening 1

[ceci1628]

I have been reading IBC and IRC 2012 and still cannot figure this out. I'm hoping someone with more braced wall design experience can help. I am doing investigation work on a house in Virginia. The house is in SDC A and 90 mph wind and built per IBC 2006. One of the brace wall line is at the double garage doors. The openings are 9'-6" wide. The 27" CS-WSP braced wall panel above is sitting entirely over the garage door opening. (see attachment in link) The design of the lower level braced wall compose of three 20" CS-PF panels.

I read IBC 2012 2308.12.6 Irregular structures - 3. Where the end of a required braced wall panel extends more than 1 foot over an opening in the wall below, the structure shall be considered to be irregular. The entire section 2308.12 is requirements for SDC D or E. Does this mean the condition is acceptable for my project.

Thanks!

 

[Archie264]

I'm guessing you'll find your answer in one of these guides, particularly the last one:

http://www.fairfaxcounty.gov/dpwes/publications/wind_bracing/

http://www.fairfaxcounty.gov/dpwes/publications/wind_bracing/wind_bracing.pdf

http://www.fairfaxcounty.gov/dpwes/publications/wind_bracing/simplified.pdf

http://www.fairfaxcounty.gov/dpwes/publications/wind_bracing/wall_bracing_training_2009.pdf

 

[EngineeringEric]

if the house was built per 2006, it was built after 2003. at which case it is most continuously sheathed, at which point there is no reason to look at that gable end as only 27" wide CS-WSP panels, use the full length if possible (tied top and bottom).

As for the design, I would think that is acceptable, widen your panels so the ends of the panels are closer to the CS-PF panels. Since they are portal frames they must have a continuous header and tension strapping for the framing above. If the wall was built per 2006 IBC why are you trying to make it conform with 2012 IBC... and my understanding is that nearly all of Virginia is 2009 IBC/IRC (or the VCC/VUSBC)?

 

[EngineeringEric]

Archie,
Nice posting to Fairfax! i guess they just have either a huge budget or some great foresight to make such great references.

 

[Archie264]

Eric,

Well it sounds like you actually understand it and actually answered the OP's question. As for the guides, I think Fairfax County did it in conjunction with Chesterfield County so perhaps together they had the budget for it.

 

[ceci1628]

Thank you Archie264 and Eric. Eric, you are right that the continuous header will transfer the forces. The Fairfax county references are great, but I couldn't find additional information on the specifics of the BWP being above an opening.

Yes, VA is still using 2009. I had to use IBC 2012 (ACI318-08) to justify a plain concrete basement wall design in the same project. I got carried away and am still using 2012 editions. Thanks again!

 

[asixth]

I don't practice in the US but its common to have offset shear wall panels between storeys where I am. The floor diaphragm distributes the shear forces and the floor systems acts as an outrigger to distribute out the overturning moments to the loadbearing elements.