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RE: 'Epoxy creep' factor in Big Dig death

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Keep in mind that there is a difference between seismic cyclic loading (which is not long term constant tension) and the constant tension over a LONG sustained period of time in the case of the Big Dig situation.  For seismic purposes, an epoxy anchor would likely only be loaded in tension for minutes if not seconds.  For the Big Dig, we are talking tension for months and years.  BIG difference (yes, slight pun intended).
 
Regards,
 
Scott
Adrian, MI
-----Original Message-----
From: Josh Plummer [mailto:josh.plummer(--nospam--at)cox.net]
Sent: Tuesday, July 10, 2007 9:38 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: 'Epoxy creep' factor in Big Dig death

Well, the question I have is who's anchors were used?  And, what do the engineering reports say about the use of those anchors in constant tension?  Here in seismic country Epoxy anchor perform much better than equivalent mechanical anchors.  If my memory is good, I believe that many of the engineering reports on mechanical anchors have limitations on them not being suitable for cyclic loading (like you might get in highway projects).
 
What I'm getting at is that if the engineering reports and all the manufacturer's literature say that it's okay to use those fasteners for that type of project, then why is it the engineers fault?  Doesn't seem criminal at all to me....  Especially when so many of the other fastener limitations are so well documented.
 
I'll grant you that for a project this big he (or she) probaly should have inquired about the type of testing and the duration of testing that was performed.  But, if the manufacturer is swearing up and down on a stack of bibles that they've tested for these cases, then I'd be fine using them for those situations.
 
Sincerely,
 
Josh Plummer, SE


From: Donald Bruckman [mailto:bruckmandesign(--nospam--at)verizon.net]
Sent: Tuesday, July 10, 2007 9:04 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: 'Epoxy creep' factor in Big Dig death

Essentially, the engineers used glue to hold 12 tons of concrete in the air.   Seems almost criminal.

 


From: Paul Blomberg [mailto:paul.blomberg(--nospam--at)gmail.com]
Sent: Tuesday, July 10, 2007 8:10 AM
To: seaint
Subject: 'Epoxy creep' factor in Big Dig death

 

FYI, here is a link to some information on the ceiling collapse in Boston

 

Paul.