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RE: sandwich panels in seismic design category D?

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Scott:

As Tom kind of pointed out, AC04 does now allow evaulation and
"acceptance" of SIP shearwalls with or without the sealant (which has some
sealant like behaviour) _IF_ tested per the Appendix A (and B) criteria.
Make sure that you are looking at the latest and greatest AC04.  The
pre-March 2003 AC04 would have limited the use of SIP shearwalls to SDCs
A, B, and C with no methd to evaluated SIP shearwalls for the other SDCs.
The addition of Appendix A (which is in large part Tom's "baby") changed
that.

FWIW, Appendix A "re-introduces" ductility into a SIP shearwall by
requiring there to be a intermediate panel joint within the length of the
shearwall.  In other words, the SIP shearwall must be comprised of two SIP
panels rather than just one SIP panel when resisting seismic loads.  This
creates a "slip plane" where the two SIP panels can move/rock relative to
each other (i.e. a shear plane).  If I had permission from the "powers
that be" in my company, I could show you a video that shows this slipping
of the two panels.

Regards,

Scott
Adrian, MI


On Mon, 13 Nov 2006, Tom Skaggs wrote:

> The code provision that disallows adhesives was first included in the 2000 NEHRP Provisions.  I was part of the wood subcomittee (TS7) where this item was discussed.  Based on shear wall testing by Professor Dan Dolan and I believe APA (this was before my tenure).  The testing was of wood frame shear walls sheathed with wood structural panels.  The panels were attached with nails as well as a rigid adhesive.  The adhesives resulted in increased strength and stiffenss of the walls, however, the normal ductile nature of the failure was lost.  The concern from TS7 is that the adhesives would result in walls being subjected to higher demands, thus shifting failures to either end posts or holddowns (or collectors).  Hence the "ban" on adhesvies.
>
> The IBC used the NEHRP Provisions as a resource document.  This provision was implemented in the 2000 IBC.  ICC ES has interpreted this provision as applying to SIPs panels, since SIPs panels use sealants during the construction.  In my opinion, ICC ES is showing due dilagence in asking if the sealants shift the normally ductile failure mode to a non-ductile failure mode.  Current Appendix A and B of AC04 is intended to show, via cyclic testing, that the sealants do not result in brittle failures.
>
> Tom
>
> -----------------------------------------------------------------------
> Thomas D. Skaggs, Ph.D., P.E.
> Senior Engineer
> APA - The Engineered Wood Association
> 7011 S. 19th Street
> Tacoma, WA 98466
> ph: 253/565-6600
> fx: 253/620-7235
> -----------------------------------------------------------------------
>
>
> -----Original Message-----
> From: Haan, Scott M POA [mailto:Scott.M.Haan(--nospam--at)poa02.usace.army.mil]
> Sent: Monday, November 13, 2006 9:38
> To: seaint(--nospam--at)seaint.org
> Subject: RE: sandwich panels in seismic design category D?
>
> Scott:
>
> Thanks.
>
> It was pointed out to one of my coworkers by an ICC engineer that 2006 IBC
> 2305.3.10 Adhesives says you can't use adhesives alone or in combination with
> mechanical fasteners to resist seismic forces in seismic design category D,
> E, or F.  We were told it is discussed in the IBC commentary.
>
> My coworker was also told that ICC acceptance criteria AC04 says that
> sandwich panels can't be used to resist seismic forces in seismic design
> category D because of this code requirement that adhesives can't be used.
>
> Scott.
>
> -----Original Message-----
> From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
> Sent: Wednesday, November 08, 2006 7:10 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Re: sandwich panels in seismic design category D?
>
> Scott:
>
> Actually, the most current version of AC04 (since March of Feb 2004, but
> has since been "tweaked") has a criteria for evaluating the use of SIP
> shearwalls in _ALL_ IBC Seismic Design Catergories.  There is now an
> Appendix A that does matched testing between a SIP shearwall and a
> stick-framed shearwall and if the SIP wall meets bascially 85% or so of
> certain cirteria of the stick-framed wall (i.e. energy dissipation,
> allowalbe story drift, stiffness criterion, and peak strength).
>
> Now, to my knowledge there are no SIP manufactures that have completed
> such testing AND gotten an updateed ICC-ES report with such evaluation
> included.  I know that the SIP company (Insulsapn) that I work for
> part-time is in the process of completing the testing but does not yet
> have an updated report.  Last time I checked Premier does not have an
> updated report as of yet, but I am fairly sure that they have completed
> testing.
>
> Regardless, there are projects with SIP shearwalls going up in high
> seismic areas.  We are currently finishing up a home in the Tahoe area
> (UBC Zone 3, but HUGE seismic mass due to HUGE ground snow
> loads...something like 300 psf).  We have some preliminary test
> information from some of our earlier Appendix A testing that I can supply
> on a case by case basis that engineers and code officials can use as a
> basis to determine if they approve the use of SIP shearwalls.
>
> If you want to discuss this further, then feel free to contact me
> privately and I can get you my mobile phone number if you want to call me
> (I am currently at the Timber Framers' Guild Conference).
>
> Regards,
>
> Scott
> Adrian, MI
>
>
> On Wed, 8 Nov 2006, Haan, Scott M POA wrote:
>
> > Are wood panel / foam core sandwich panels being used anywhere in Seismic
> > Design Category D?  ICC AC04 now says that they are allowed only in Seismic
> > Design Categories A, B and C.   It is my understanding that the 2000 ICC
> > evaluation reports were silent on this but that ICC evaluation reports
> based
> > on the 2003 IBC say specifically they are only allowed in seismic design
> > category A, B and C.
> >
> >
> >
> > They used to use these panels in Anchorage Alaska to brace residential
> > buildings frequently.  I remember one manufacturer had an engineer down in
> > Oregon do their calculations for them and I think it was Premier Panels or
> > something like this.
> >
> >
> >
> > Where are the bodies?  I would like to know why they are not allowed
> anymore
> > - were their failures in Northridge or something? Are these things being
> used
> > in California or else where in seismic design category D?
> >
> >
> >
> > Did some Cheechako [no offense intended to any Cheechakos reading this]
> > committee decide they wanted to legislate that you can't use sandwich
> panels
> > like loghomes in Alaska where there is a history of them performing?  There
> > were no reports from the November 3, 2002 Mw7.9 Mentasta earthquake that
> > sandwich panel braced houses in the Fairbanks area had to be condemned.
> >
> >
>
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