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Re: residential plywood diaphragm glue

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I've called for 3M 5230 several times in the past. It had an NER report that
gave shear values which were pretty high. It could be used to strengthen
shear walls with fewer nails and less splitting. Or for built up columns or
plates as required. I understand, however, that 3M failed to renew it's NER
report several years ago. Structural use of it now probably requires
testing. I'd be interested in more reports and comments about this material.

----- Original Message -----
From: Martin W. Johnson <MWJ(--nospam--at)>
To: <seaint(--nospam--at)>
Sent: Tuesday, January 11, 2000 9:06 AM
Subject: RE: residential plywood diaphragm glue

> We often use 3M 5230 adhesive when we install new wood framing in retrofit
> It has a more elastic "gummy" hardness after it dries that allows the
nails to
> continue to form ductile bending mechanisms.  We did some limited testing
> samples using it after the Northridge EQ and were able to develop
> strengths and ductilities.  Being more elastic, the glue tends to roll
into tiny
> beads as the nails bend and the deformations become large.  We were even
able to
> get significant ductility using screws in parallel with the glue.  It's
too bad
> we didn't have the time or budget to carry through and publish the