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Re: The Engineering Paradigm (WAS Re: Op

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Christopher Wright wrote:

>>Actually your mention of the Challenger is a perfect example of envelope 
pushing and unexamioned successes which eventually led to tragedy.<<

Actually, the Challenger disaster was the result of considering ECONOMICS and 
PUBLIC RELATIONS ahead of SAFETY.  Because of the extreme cold in Florida at 
the time of the scheduled lift-off, the scientists involved in the rocket 
design were polled about going for a lift-off.  IIRC, they overwhelmingly 
voted NO.  Because of the publicity of a "teacher in space", the decision was 
to go with the lift-off.  (I forget if the scientists were polled again with 
that consideration or whether it was an administrative decision based on past 
successes with launches.  Needless to say, the launch did get publicity, but 
not the publicity that was desired.)

>>It wouldn't surprise me to see something similar happen with finite element 
applications. Maybe even LRFD.<<

Hear! Hear!  I agree.

The Millennium Bridge in London had been touted as being more slender than 
any other foot bridge, and is now experiencing problems because of 
"pedestrians falling into step on a swaying structure."  Napoleon knew about 
the effects of solders marching in step across bridges, but apparently 
someone "forgot" about that.

The Tacoma Narrows bridge was touted as being more slender than any other 
suspension bridge, and the results of "we know more than those old f**ts" was 
amply demonstrated when the bridge collapsed.

The Bronx Whitestone Bridge (I believe) was designed to the same slenderness 
as the Tacoma Narrows Bridge.  I remember crossing the bridge in the 1940's 
when it was being reinforced and my father explaining that they were putting 
stiffening trusses on it.  (My father was a civil engineer with the New York 
City "Board of Estimate."  At that time, I didn't know what "stiffening 
trusses" were or why they were important, and my father did not go into any 
further explanation.)

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

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