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RE: STANDARD PRACTICE

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Christopher Wright, M.E., wrote:


I think William LeMessurier's error in the Citicorp wind load analysis
for the skyscraper design was caught by someone reviewing his original
design.

Bill LeMessurier found the error himself.  He presented the project to the students in a class that he was teaching, and one bright student asked some fundamental questions that got him thinking.  So he dug up his old calculations and personally revisited his own work. 

And I daresay that the deficiency in the Hyatt-Regency skywalks
would have been caught sooner had the calculations been formalized in a
report.

The Hyatt disaster also had nothing to do with the lack of calculation submittals.  It was primarily the result of very poor project communications, particularly regarding the shop drawing review and change order request processes.  The EOR presented his perspective on this to SEAoT earlier this year.  

Submittals are much more the rule than the exception here on the dark
side, because they're used in customer design reviews .My own experience
is that formal submittals make the design intent a good deal more
apparent. I've also found that simply organizing results for a formal
submittal is a good check for internal consistency. Building construction
may be a lot different than mechanical design, but I'd find it damn near
impossible to review a design for adequacy simply from the drawings--it'd
take forever, for one thing, and for another, if I did happen to find
something that didn't fit, it'd take just that much longer to figure out
who was wrong without the original design basis.

By the "dark side", I assume that you are referring to mechanical engineering, and not to the Land of Hubert and Jesse.  My son is a mechanical engineer at NASA.  Comparing structural engineering practice to mechanical engineering practice is like comparing apples to oranges.  They are different fields of endeavor, with different issues.  That is why I would never try to comment on mechanical engineering issues. 

And when I'm doing any testimony where design is an issue, the first
thing I want to see are calculation summaries so I can determine design
intent.

If your idea of expert witness testimony centers on reviewing the original calculations, you must be a pretty ineffective expert.  Normally, an expert witness is supposed to be rendering an independent opinion of the adequacy of a design.  It's the building or bridge that failed, not the calculations.  The failure may or may not be related to design.  There could be a great design supported by lousy calculations, or vice versa.  There could also be a great design supported by wonderfully detailed and organized calculations, but the structure still failed through engineering errors during construction administration (as with the Hyatt).

Regards,

Stan Caldwell

Land of Georges