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RE: 'Epoxy creep' factor in Big Dig death

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This was certainly a terrible tragedy.

But, as I understand it, epoxy anchors typically have a safety factor of at
least 4:1.

If it were really "epoxy creep" then why didn't more panels fail?

I guess my point is that maybe the installation was faulty; perhaps the hole
was not cleaned out or the epoxy incorrectly applied, etc.


I think we can all look back at details we've done over the years and wonder
"what was I thinking?"

I think it could be classified as "seemed like a good idea at the time"

Obviously, some sort of redundancy should have been built into the design;
but say the panels were supported by four rods; at 4:1, the panel should
have only needed ONE rod to support its dead weight...at least the panel
would have come loose and repairs been able to be made to stabilize it prior
to failure.

It appears that there might be more to this story...


Still, an awful waste of human life.




David L. Fisher SE PE
Senior Director

Cape Cod Grand Cayman Holdings Ltd. - Cayman
Fisher+Partners Structural Engineers Ltd. - Cayman
372 West Ontario Chicago 60610
75 Fort Street Georgetown Grand Cayman BWI
319 A Street Boston 02210


312.573.1701
312.573.1726 facsimile
312.622.0409 mobile

www.ccgch.com
www.fpse.com





-----Original Message-----
From: Gary L. Hodgson and Assoc. [mailto:ghodgson(--nospam--at)bellnet.ca] 
Sent: Wednesday, July 11, 2007 6:49 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: 'Epoxy creep' factor in Big Dig death

If the issue is epoxy creep, then this could apply to any epoxy anchor 
out there in tension.  These anchors had only been in place a year or 
two. if I am not mistaken.  I still think the problem is in drilling and 
installing the epoxy upwards.  I think Newton's Law of something called 
gravity is against you.  I recently called a manufacturer about 
"drop-in" anchors being used by a contractor to fasten window framing to 
balcony ceilings and the manufacturer's rep said no they weren't 
suitable for that case, but their literature didn't say any such thing.
Gary

Josh Plummer wrote:
> 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. 
>
>
http://news.yahoo.com/s/ap/20070710/ap_on_re_us/big_dig_1;_ylt=Andn7WOnYmsxA
vZeYPgpyk8E1vAI
>
>  
>
> Paul.
>

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