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who is an expert?

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(sorry if this posts twice)

With all due respect to Gail and everyone out there...

>From her posts, she seems to be an expert in concrete. Anything I say here
is with all due respect to her, but I too must some of her statements.

Our company is not, neither am I, a concrete expert. I don't know if I would
call us an "expert" in anything, but we have our strengths and weaknesses.
We are always building on that and trying to broaden and diversify our
knowledge and experience. We are a small firm that does just about
everything 3 stories and less. I would never give advice or take a job
involving pre/post stressed concrete, a parking garage, etc. But concrete
repair on aging structures is a constant and continuing problem, and local
engineers are going to be called upon to come up with econmically viable

 Funny thing is, we actually did a repair job on transfer station (two story
structure where garbage and recycling trucks dump their stuff to be sorted
and hauled), and it was originally designed by Walter P. Moore. It is a
gov't owned structure whom we have a continuing contract with. They called
us, not our buddy Eric from WPM to fly in from MO. Shoot, our total fee was
probably the site visit from them. Are we self proclaimed concrete repair
experts? NO, not at all. But it was a pretty straightforward RC structure
with excellent drawings from WPM. We thoroughly examined the problem, did a
ton of research, and came up with a very conservative solution due to the
heavy loads applied daily to this slab. We did not determine the exact cause
of the problem (large diagonal cracks that leaked "juice" to the lower
story) but had several theories. From all the research we have done it seems
that sometimes it is impossible to determine the exact cause and effects of
concrete cracking, delaminations, etc. We ended up routing and pressure
epoxy sealing the cracks and supplied steel beam framing epoxied and bolted
beneath the slab to support the full design loads, a bypass framing system.
It was not that expensive, we knew this would solve the problem with a high
factor of safety, and will not result in a call back. We, along with the
contractor, did state that the cracks may reopen and would require
maintenance over the lifetime of the structure. That was over 2 years ago,
no calls.

So were we wrong? What should we have done? What would YOU have done? The
local gov't doesn't have the money to fly Gail or Eric (the original SE
company) down and do nuclear testing and so on and so forth.  We are not
concrete experts, although we have a fair amount of knowledge on the
subject. Should we have told them to fly in an expert because we didn't want
to buy more books and do the research? Isn't part of the job experience
also? Why shouldn't we pick the brains of hundreds of other SEs with similar
experiences, telling us what they did, what they would do, what they would
not do, things to avoid? I learned from Gail not to use "polyurethane
injection for a slab with
traffic loading", this is from the internet. BTW, what was her

  Aren't some repairs difficult for even an expert to determine and solve
with 100% satisfaction, thus possibly resulting in a call back or a trial
and error process? Isn't the point of research to avoid this? How do you get
to be an expert?

If I am way off here then let be scolded, but I am confused. I am not sure
what we should do then when something comes up WE haven't seen before.
Doesn't this happen all of the time? Obviously certain things do require
specific experience and knowledge. Like I said, for ex., I would not touch
prestressed concrete, I don't know anything about it. I would like to hear
other opinions. I say all this with all due respect to Gail, who made a good
point, but maybe went overboard or did not explain what exactly she meant,
although I THINK I understand. I mean, can I spec repair to a sidewalk or
something trivial like that, then work my way up? How do we draw the line?
Where can we get the best and latest resources on concrete repair and
diagnoses? I have the 1999 ACI Concrete Repair manual, what else?

Please, my more experienced SE mentors, clarify this cloudy subject...

Andrew D. Kester, EI
Structural Engineer

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