Being built does not mean that it went through the city permit process this year. Utah accepted the IBC 2006 in Jan. of 2007. If the plan went through the city last December it could have been designed and accepted under the 2003 code. Now as in my other post, 2003 code did not specifically tell you what h/w to use. So they may have used that design process. I am guessing that someone screwed up and it was never caught, or they used the 2*w/h reduction value (reducing the allowable capacities) which was added to the 2003 IBC.
Example of the 2*w/h per IBC 2006 Table 2305.3.4 footnote a.
Say you have a shear wall loaded with 210plf, try 3/8” sheathing with 8d at 6-12 GF = 220plf . Height = 10ft, width = 4ft. h/t = 2.5. This does not meet the 2:1 ratio. However per the footnote a of Table 2305.3.4 you and reduce the capacity by 2*w/h, 2*4/10 = 0.8, therefore the 0.8*220 = 176plf N.G.. Use 7/16 sheathing with 8d at 4-12 GF = 0.8*350 = 280plf OK.
Not magic but it does allow you use smaller widths of walls.
Jason
-----Original Message-----
From: Jeff Hedman [mailto:jeff_h@lrpope.com]
Sent: Friday, December 07, 2007 11:43 AM
To: seaint@seaint.org
Subject: RE: Perforated shear walls
Jason,
The building was built here in St. George this year (which would be IBC 2006). In fact the building was just completed in the last month or two. I am just wondering if there is a wood shear wall method that was used for this situation that I am unaware of (or magic). I have had to design buildings like this before and have had to get the architect to change the wall lengths, use strong walls, or in one case we changed to masonry.
Jeff Hedman , E.I.T.
L.R. Pope Engineers & Surveyors, Inc.
1240 East 100 South Suite # 15B
St. George, Utah 84790
Office: 435-628-1676
Fax: 435-628-1788