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<DIV><FONT face=Arial size=2><STRONG>Hi Terry,</STRONG></FONT></DIV>
<DIV><BR><FONT face=Arial size=2>> Jude - Regarding your concern about
horizontal shearing stress. Is that <BR>> concern that the panel or rib might
fail or degrade in some way as a result <BR>> of whatever shearing stresses
might be present? Is your concern that these <BR>> items might fail or
degrade more readily than a solid item?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG>I think so. When I think of a
composite structural member supporting a floor or a ceiling, I know the
beam is engineered to resist any potential load by a significant
factor. This would be too stiff in a piano sb design, so I would be
concerned that the shearing strain from the string bearing load might be an
issue if not in delamination than checking the cross grain laminations. Then
again, the only problem might be my understanding of the problem and I'm looking
at addressing this presently. Give me some time.</STRONG></FONT></DIV>
<DIV><BR><FONT face=Arial size=2>> <BR>>>From what I've experienced,
building these items with adhesives such as <BR>> Titebond yields excellent
results. Some folks would have concerns regarding <BR>> glue "creep" with
Titebond. I don't, but if one did, build the panel or ribs <BR>> with a
glass-hard adhesive like two-part urea-formaldehyde. Is "creep" where <BR>>
your concern center? I used a modified two-part urea-formaldehyde adhesive
<BR>> on the panel that Richard Brekne wrote about. Certainly the bond with
that <BR>> adhesive is way stronger and sheer-resistant than the wood itself.
And with <BR>> respect to the panel, I should think that crossing grain
angles between <BR>> laminations would also make the entire assembly more
resistant to stress <BR>> from any direction - including sheer.<BR>>
<BR>> Just my thoughts, FWIW.<BR>> <BR>> Terry Farrell
<BR>></FONT></DIV>
<DIV><FONT face=Arial size=2><STRONG>That's a very good and focused question. I
don't think my concern is with the creep but perhaps with the
adhesive. Perhaps I'm just being a nervous Nellie and if the load does not
exceed its demands, we're ok. You also have the advantage of the
assembly being attached at both ends (I have even more concern about a laminated
key that is working as a cantilever, but then the loads aren't so great here).
I'll get back to you when I have a clearer understanding of what I've read on
the subject and have perhaps made some experiments myself. Man I wish I had some
of those cool devices Mr. Hoadley has at UMass.</STRONG></FONT></DIV>
<DIV><FONT face=Arial size=2><STRONG></STRONG></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG></STRONG></FONT> </DIV>
<DIV><FONT face=Arial size=2><STRONG>Jude</STRONG></FONT></DIV></BODY></HTML>