Group: comp.lang.functional · Group Profile
Author: Jerry AvinsJerry Avins Date: Mar 1, 2007 08:43
Ulf Wiger wrote:
...
> I understand that the Tacoma Narrows Bridge was an sleek new
> design, partly driven by cost pressure. Still, the effect
> (aeroelastic flutter - a term that wasn't invented until 7 years
> later) that led to its collapse had never been seen before, and
> the disaster was unexpected.
The disaster was predicted before the bridge was completed. David B.
Steinman, then an upstart engineer who had already incurred the
displeasure of the established bridge-building community by setting out
on his own instead of signing on as an apprentice, got into a
letters-to-the-editor feud with Leon S. Moisseiff, Gertie's designer and
a member of that New York community. It's bad form to criticize a
colleague's work, and the people who designed the George Washington
Bridge and probably knew that Steinman was right kept out of it. The
Bronx-Whitestone Bridge was nearly a sister to Galloping Gertie*.
Steinman concluded that, given the strength and direction of the winds
over Long Island Sound there, it would remain safe. (Gertie's collapse
had catapulted Steinman into bridge-building stardom. He didn't
disappoint.)
WW II broke out before the Bronx-Whitestone Bridge could be stiffened,
and it served as built until nearly 1950. I once rode a bicycle across
it on a moderately windy day and during one lurch both wheels left the
pavement. Eventually, a stiffening truss was added (replacing the
walkway, to the dismay of many) and the bridge calmed down.
> (While it may sound terrible, having as a core requirement that
> "if your product fails, people may die" tends to have a sobering
> effect on many aspects of engineering. The hacker adage "besides the
> fact that it didn't work, what do you think?" doesn't seem quite
> as funny when "didn't work" can be substituted with "people died"...)
Even more effective would be "If your product fails, _you_ may die."
:-) It's sobering to work on a product where "system crash" means broken
glass and twisted metal and maybe blood on the floor. Been there.
...
Jerry
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* I prefer the nickname because there is a present-day Tacoma Narrows
Bridge which is obviously not the same.
--
Engineering is the art of making what you want from things you can get.
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