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RE: Multi-story wood framed w/lots of openings

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Someone else already has done cyclic testing on perforated shear walls.  Where do you think that the reduction factor chart comes from!  The testing was done in Japan back about 10-15 years ago with input from the US wood associations.  Shake table tests were done with various wall opening heights and lengths and the performance was measured to build the reduction charts.


Personally, I would rather rely on an empirical method that has been tested and has a record of performance rather than use a rational (i.e. theoretical) method that may or may not be accurate in real world conditions.


~~ Eli Grassley


-----Original Message-----
From: Bill Allen, S.E. [mailto:T.W.Allen(--nospam--at)]
Sent: Thursday, March 10, 2005 10:56 AM
To: seaint(--nospam--at)
Subject: RE: Multi-story wood framed w/lots of openings


I guess this is one (of the few) times I agree with Dennis. If I’m going to use a shear wall with openings, I’m going to strap across the openings using the methodology presented in the Seismic Design Manual (Volume II, starting on page 40) published by the Structural Engineers Association of California. Often, I have cases where I physically cannot transfer the load around the opening. When that happens, I use two piers or some other solution. Perhaps APA (or someone else) can do some cyclic testing on a perforated shear wall assembly and ask SEAOC to review and comment.


T. William (Bill) Allen, S.E. (CA #2607)


Consulting Structural Engineers

V (949) 248-8588

F (949) 209-2509


-----Original Message-----
From: Rhkratzse(--nospam--at) [mailto:Rhkratzse(--nospam--at)]
Sent: Thursday, March 10, 2005 10:36 AM
To: rgarner(--nospam--at); seaint(--nospam--at)
Subject: Re: Multi-story wood framed w/lots of openings


In a message dated 3/10/05 10:29:04 AM, rgarner(--nospam--at) writes:

I just looked at the AF&PA perforated shearwall document.  The top detail of Figure 5 on page 8 relies on nails in withdrawal to resist uplift.  I don’t agree with this.  Anyone else?  It would be easy enough to strap this joint, however, as shown in the other connection in this detail.

I have similar concerns.  I recommend watching Simpson Co.'s video of a dynamic test of a plywood shear wall, with the end studs bouncing about an inch off the bottom plate as the forces reverse, tearing the plywood away from the framing near the bottom of the end stud, etc.  Essentially the 'quake disassembles the wall.  It put the fear of (earthquake) into me!

Ralph Hueston Kratz
Structural Engineer

Fax 510-215-2430

724 McLaughlin Street
Richmond CA 94805-1402 USA