From: merrick group <merrickgroup(--nospam--at)compuserve.com>
Date: Tue, 11 Jan 2000 13:34:21 -0500
Martin W. Johnson has called attention to the ?3M 5230 adhesive?, a ?break
for shear walls!
I was talking about whether or not glue adds rigidity to floors. I argue
that it does,
hence rigid diaphragms. It seems that this glue may add strength and
rigidity but is
not brittle. That is good.
I like that glue! Is it the only product that behaves in this way? I
suspect a little
competition by other glues would get your funding. I am emailing another
interested in testing shear walls if he get started on a project for other
glues, I?ll tell
It would be important that if a glue was used, that the HD strengths were
the maximum possible strength of glued and nailed plywood. I suspect in
using the glue
that Martin knows of its maximum probable strength.
There might be a difference between static tests and dynamic. You know,
the: more elastic
?gummy? thing. Its probably not what: wiggly. So I pulled out my gum to see
if it snapped
at different speeds. It seems to be dependant on how cold it is and if it
real bubble gum. It wasn't wiggly like jello.
David Merrick, SE
Recall message from Martin W. Johnson
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
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
beads as the nails bend and the deformations become large. We were even
get significant ductility using screws in parallel with the glue. It's too
we didn't have the time or budget to carry through and publish the results.