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Re: The Engineering Paradigm (WAS Re: Op

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Well,

Now we can also include the Concorde mishap.....

Are the planes getting old and rusty.....was there faulty
maintenance.....did the British, who can't seem to design a pedestrian
bridge correctly,  prevent such an accident by removing the wheel
flaps....???? plus sticky rods on Alaska Airl. jets....should these planes
perhaps have been designed in Pakistan  .... ???

jim


----- Original Message -----
From: "Christopher Wright" <chrisw(--nospam--at)skypoint.com>
To: "SEAOC Newsletter" <seaint(--nospam--at)seaint.org>
Sent: Sunday, August 06, 2000 2:05 PM
Subject: Re: The Engineering Paradigm (WAS Re: Op


> >Actually, the Challenger disaster was the result of considering ECONOMICS
> >and
> >PUBLIC RELATIONS ahead of SAFETY.
> That was only one of the causes. Like the Titanic sinking there were
> several 'but-fors.' The design itself was tricky. I'd worked with an 8
> foot diameter test tank which had a clevis type joint and O-ring, and it
> was always a flaming bitch to assemble. When I saw a diagram of the joint
> a day or two after the disaster, I was about 99% certain that it was a
> seal problem like we'd had with the Perry test tank.
>
> One or the other of the Feynman books ('What Do you Care What Other
> People Think?' or 'Surely You're Joking Mr Feynman,') has a couple of
> chapters on the Challenger explosion. They'd had problems during design
> and test and in previous launches, but didn't do much about the design.
> Joint assembly was also tricky which led to difficulty with mating the
> seal and the sealing surfaces. Feynman was widely credited with
> discovering the seal problem with his video demonstration, but he seems
> to say that he was put onto the idea from an Air Force officer on the
> committee. Feynman has a detailed discussion of all the statistical arm
> waving that NASA used to convince itself of reliability, in which they
> progressively lowered the bar on thermal requirements. The last straw was
> apparently pressure from the supreme NASA PhB to get Christa McAuliffe
> into space because she was scheduled to talk to Reagan that day. Between
> the design, the failure to deal with problems uncovered testing, foolish
> interpretation of cooked-up reliability statistics and management and
> political pressure, you can pick any or all as causes.
>
> In philosophical terms, that's and interesting thing about disasters of
> all sorts--from the Johnstown flood to the TMI accident sinking to Pearl
> Harbor. All were chains of events, the absence any one of which could
> have made it into a non-event.
>
> >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.
> Petroski mentions this alteration and some others made after the Tacoma
> Narrows bridge came down. When I was a kid in Cincinnati in the 40's
> bridges were fascinating, especially Roebling's suspension bridge across
> the Ohio, because of the film of the Tacoma Narrows Bridge. They still
> fascinate me. What's really interesting about TN is the curious response
> of the towers and cable--with all that weird dynamic loading  both look
> absolutely rock solid even as the deck drops into the water. No apparent
> damage to either the towers or cable--I find that curious.
>
> Christopher Wright P.E.    |"They couldn't hit an elephant from
> chrisw(--nospam--at)skypoint.com        | this distance"   (last words of Gen.
> ___________________________| John Sedgwick, Spotsylvania 1864)
> http://www.skypoint.com/~chrisw
>
>
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