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Re: Causes of a "fatal flaw?"

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>Two studies published at
>http://www.muckraker.org/investigations/steelhome.html attempt to
>explain the fundamental causes of the failure of the "pre-Northridge
>connection.

I've got some real problems with this web site. First, the site explains nothing and proves nothing. Consider the statement
>  'testing and finite-element analysis led to the discovery of
> the cause of the prying action mentioned in the paper. As
> the beam is flexed, one side of the beam's flange contains a
> large compressive stress component while the other side of
> the same flange contains a large tensile stress component. The
> result is often the separation of the beam flange from the
> column flange in the form of a weld or flange fracture or
> a column flange divot, which was often seen during building
> inspections following the Jan. 1994 Northridge earthquake, said
> Richard.'
It's only a restatement of the obvious, pretending to be some wondrous discovery. The gap between '...large tensile stress component.' and  'The result is often the separation...' is arm-waving. Not even Indiana Jones would make such a leap of faith.

The discussion of brittle fracture is tripe. So is the following:
> The story of engineering drama was recently published in Structural
> Engineering magazine. While this publication's target
> audience is 30,000 licensed professionals, the article's essence
> is easily understood by non-engineers.
If it were so easily understood, the author wouldn't have gotten it so far wrong.

Second, the phrase
> 'Richard is co-owner and inventor of SSDA's  proprietary SlottedWeb?
> seismic connection design, which competes with the
> now popular reduced beam section (RBS) connection as  proposed
> in FEMA's study.'
shows clearly that the studies are meant to flog an invention, not provide useful information.

I don't doubt that those connections had serious problems and I suspect I know what happened, but the web site is technical and professional dreck.

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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