Integrated Buildings & Structures

The American Wood Council provides three acceptable methods for designing wood shear walls to resist lateral forces, including Individual Full-Height Wall Segments, Perforated Shear Walls and Force Transfer Shear Walls (Jared Hensley, in the January Structure Magazine). Obviously, each method has multiple advantages and disadvantages. I was wondering the preferred method of people who deal with this in either their work or personal life.

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Joshua Sims S.M.ASCE
Student
Falls Church VA
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Joshua, often times the type of shear wall method depends on the layout of the wall, such as if windows are present.  I am an engineer who has never used the perforated method, so I can't compare it to the other methods.  If the shear wall has no windows, I typically use the segmented method.  If windows are present, I use the Force Transfer Around Openings method.  This method is the most accurate for walls with windows and may be more involved when dealing with the calculations, but the benefits are worth the added effort.

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Kirk Uchytil
Structural Engineer
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As has been mentioned when there are a minimum number of openings in the wall the segmented approach works very well. But it is important to note that a hold down is required on each side of each segment and these can be expensive to install.  For a wall having 2 openings 6 hold downs will be needed.  For walls with  multiple openings the PSW method works really well since a hold down is just needed at each end of the wall regardless of the number of openings.  Plus, it is a relatively easy analysis to make.  The FTO method is based on using a rational analysis and historically there have been many questions raised as to what constitutes an acceptable rational analysis.  Recent research by APA has shown that many of the previously used rational analysis methods either over or under estimated the shear wall performance.  And it is by far the most time consuming method of analysis.

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Thomas Williamson P.E., F.SEI, F.ASCE
MANAGING PARTNE
T. Williamson - Timber Engineeering
Vancouver WA
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Original Message:
Sent: 03-08-2018 08:18
From: Kirk Uchytil
Subject: Wood-Framed Shear Walls

Joshua, often times the type of shear wall method depends on the layout of the wall, such as if windows are present.  I am an engineer who has never used the perforated method, so I can't compare it to the other methods.  If the shear wall has no windows, I typically use the segmented method.  If windows are present, I use the Force Transfer Around Openings method.  This method is the most accurate for walls with windows and may be more involved when dealing with the calculations, but the benefits are worth the added effort.

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Kirk Uchytil
Structural Engineer
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There are also tests that can be done to get answers. For example,

• ASTM E2126 (which I happened to originally write),
• ASTM E72, and
• ASTM E564

I'd recommend each of these depending upon your needs and application. However, I'd suggest a laboratory that is accredited under the IAS procedures following ISO 17025.
Max

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Max Porter Ph.D., P.E., Dist.M.ASCE, F.SEI
UNIV PROFESSOR EMIRITUS
Ames IA
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