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RE: IBC Conventional Light Framed Construction

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Andy,

 

It’s in the text of 2308.9.3, just following the list of the eight bracing methods (p.460, top of the 2nd column):

 

“For Methods 2, 3, 4, 6, 7 and 8, each panel must be at least 48 inches in length…”

 

“For Method 5, each panel must be at least 96 inches in length where applied to one face of a panel and 48 inches where applied to both faces.”

 

Therefore, you can’t have a 1’-0” wide bracing panel. (Not even if you continuously sheath, that requires at least 24” wide segments).

 

Gary

 

Gary J. Ehrlich, PE

Program Manager, Structural Codes & Standards

National Association of Home Builders (NAHB)

1201 15th Street, NW, Washington, DC 20005

ph: 202-266-8545  or 800-368-5242 x8545

fax: 202-266-8369

gehrlich(--nospam--at)nahb.com


From: Andy Heigley [mailto:aheigley(--nospam--at)jgaeng.com]
Sent: Wednesday, October 17, 2007 1:27 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: IBC Conventional Light Framed Construction

 

Thanks for your help.

 

Gary:  you stated that you’d have a minimum 4’-0” long panel placed at the midpoint.  This is exactly my question.  Where does it state that the minimum panel length is 4’-0”?

 

I know in the IRC it states the 16% of the length, but if you have a commercial building, you have to use the IBC. 

 

Just for example, let’s say my client wants to stay within the limits of Conventionally Framed Construction, but wants a storefront appearance and says I want the openings to be as large as code allows and spacing between windows to be minimal.  Let’s say the wall is 30’ long.  If I have a 1’-0” wall brace at each corner and one in the midpoint of the wall.  It satisfies the 12’-6” end distance, but if you look at the bracing ratio, you are only at 10% of the total wall length. 

 

Now I’ll also state that I’d never use (3) 1’-0” wide brace wall segments in a 30’ long wall to brace the building… but I’m just saying the code seems to have left some guidelines out, or I can’t find them. There should be something like a minimum length to be considered a braced wall segment, must satisfy a minimum H/L ratio or something.

 

I know I would use my engineering judgment to set minimums in this case, but if I’m to look at the details of the code, they are not there.

 

Andy