Under the 2006 IBC, Figure 2305.3.5, for perforated shear wall piers the full height to width must conform to the 3.5:1 for wind, for seismic they must meet the 2:1 to have full design capacity of the allowable panel values, however you can use up to the 3.5:1 but your allowable panel values must be reduced by 2*w/h. Remember this reduction is only on the capacity of the panel, if you increase your loading shear by the inverse you will increase your the holdown size which is not required.
Jason
-----Original Message-----
From: Jeff Hedman [mailto:jeff_h@lrpope.com]
Sent: Friday, December 07, 2007 8:48 AM
To: seaint@seaint.org
Subject: Re: Perforated shear walls
Do the full height wall piers of the perforated shear wall still have to conform to the 3.5:1 (wind) and 2:1 (seismic) height to width ratios? There is a project by my gym that has walls that do not meet the height to width ratios but each full height panel had a hold down on each end. For example, the walls in question are about 14’-0” tall and there are four panels on this particular wall that are only 2’-0” long, each 2’-0” shear panel has a hold down on each end. Has this been engineered as a perforated shear wall? Maybe the engineer used uplift straps instead of the anchor bolts to resist the unit uplift force?
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
email: jeff_h@lrpope.com