Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: big dig structural failure - epoxy anchors overhead supporting gravity

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Mark,
 
Thanks for the post.  It would be good to hear from other engineers from the Boston area.
 
I was not comfortable with the general idea of this heavy hanging "ceiling", but I never suspected that the overhead bolts were epoxied.  But it appears they were http://www.tollroadsnews.com/cgi-bin/a.cgi/XWoB!g!REduFEIJ61nsxIA. Scary.
 
Steve Gordin SE
Irvine CA
 
 
 
 
  
----- Original Message -----
To: seaint
Sent: Friday, July 14, 2006 6:14 AM
Subject: big dig structural failure - epoxy anchors overhead supporting gravity

Folks,  

I lived in California for 13 years, including 3 years in the construction industry and 10 years practicing structural engineering.  According to my recollection, I never met, worked for, or worked with ONE SINGLE engineer who would specify anchors grouted with epoxy to be used in an overhead application supporting gravity loads.  And yet, that is what was apparently used in some areas of the big dig to anchor the concrete hung ceiling to the tunnel's concrete roof.  Frankly, I am shocked that epoxy anchors were used.  Perhaps I am wrong about this.  I would appreciate comments on this.  

If that system IS acceptable, I will state categorically that the Boston area is not the place to do it.  This is due to the culture of the Boston area.  After my 13 years in California, I have spent the last six years in construction management (of buildings, not highways!) in Massachusetts.  My experience over the last six years points to a PROFOUND difference in culture and mentality with respect to attention to plan review, professional collaboration, compliance with building codes, inspection quality, use of new technologies, and commitment to excellence.  

In my work here, I attempt to hold all of us to the highest standards of design and construction, and yet on a daily basis I am met with incredulity by my colleagues, and by the architects, engineers, and contractors involved in construction of buildings here.  

During the last six years in Massachusetts I have never seen an evaluation report for a manufactured item, such as an epoxy anchor.  It simply isn't done here, in my experience.  The typical process is this: the engineer will be vague in the specs, indicating say epoxy OR mechanical anchors.  Then there may be a submittal, maybe not.  If there is, there is no follow-up.  The contractor is free to install them as he sees it.  There is no inspection required by the authorities having jurisdiction.  The inspection firms sometimes may be asked to inspect, but in general the particular individuals are not qualified to inspect such a thing.  

For instance, yesterday when I read in the paper that the epoxy had "pulled out cleanly", I told some colleagues that it seemed to me the only way that could happen was if the threaded rod was NOT galvanized.  Plain steel comes from the supplier with a coating of oil.  Incompatible with epoxy grout.  Now it looks like that's what happened.  Only in Boston could this happen with the culture we have here.  

As another example, in six years I have never seen a list of plan check comments.  It simply isn't done.  If I ever question some aspect of the design during the construction phase, no one will look into my comments, but instead the reaction will be "we have a building permit, so your question doesn't matter".  Or I am met with a stone wall of puzzled looks.  "Who are you to question the engineer?"  "Well, the engineer has his stamp on it, so it's OK."  "That's the way we've always done it."  But NEVER an answer to the question.  

This mentality in Massachusetts covers ALL aspects of construction, not just structural, but also HVAC, fire protection, civil design, egress requirements, accessible design, etc etc etc.  

My experience in California was completely different.  Plans are checked, comments are made, professionals revise the drawings, building inspectors require inspections, building inspectors require inspections by the professionals, etc etc etc.  Questions raised are viewed as an OPPORTUNITY.  

Any thoughts?  

Mark Swingle