kansas city hyatt hotel

Newsgroups: alt.folklore.urban
From: ab401@freenet.carleton.ca (Paul Tomblin)
Subject: Re: BRIDGES THAT RESONATE
Date: Thu, 16 Jun 1994 12:28:36 GMT

In a previous article, pdt@mundil.cs.mu.OZ.AU (Peter David THOMPSON) said:
>charles.zucker@support.com writes:
>>I'm doing this from memory - but there was a tragedy at, I believe, the 
>>Kansas City Hyatt Hotel on New Years' Eve sometime in the '80s. The 
>>concrete skybridge collapsed while dancers were rhythmically pounding 
>>their feet to "Satin Doll."  Many died.
>
>I'm not interested in looking through some 10 years of Reader's Digests,
>but it proved eventually to be a consequence of rather - inadequate -
>design and/or construction. I seem to recall they used half the fastenings
>they should have to support one skybridge - and then compounded the felony
>by hanging a second from it. The safety factor was <1 for capacity crowds
>on the bridges after this inspired work.

Far be it for me to interject after ssuch a well researched followup, but
here is basically what "Why Buildings Fall Down" (Matthys Levy and Mario
Salvadori) (quoting directly from the National Bureau of Standards report on
the accident) had to say about the Kansas City Hyatt Hotel disaster:
"1. The walkways collapsed under loads *substantially less* than those
specified by the Kansas City Bulding Code.
2. All the fourth-floor box beam-hander connections were candidates for
initiation of walkway collapse.
3. The box beam-hanger rod connections, the fourth-floor-to-ceiling hanger
rods, and the third-floor-walkway hanger rods did not satisfy the design
provisions of the Kansas City Bulding Code.
4. The box beam-hanger to rods connections under the original hanger rod
detail [design] (continuous rod) would not have satisfied the Kansas City
Building Code.
5. Neither the quality of workmanship nor the materials used in the walkway
system played a significant role in initiating the collapse"
It goes on to say how the "the original design, though illegal, might have
avoided the tragedy".

Note; The original design had floor to ceiling continous rods holding up all
the walkways.  The contractor decided that it would be too hard to build them
that way, so he suggested a design change in which the rods went to the upper
walkway, then another set of rods went from the upper to the lower.  The
engineers did sign off that change.  The failure seemed to occur because of
the moment applied to the beams in the upper walkway because of the offset
between the rods going up and the rods going down.  

Paul "The book actually has 10 pages on this particular disaster" Tomblin

More info is available in (this courtesy of Mark Brader):
The same disaster is discussed by Henry Petroski in more than one of his
books, but particularly in "To Engineer is Human: The Role of Failure in
Successful Design" (1985, St. Martin's Press, ISBN 0-312-80680-9).

Petroski says that the original design had the rods running from the
ceiling through the upper walkway (which was to be fastened to them by
nuts on the rods at that point) and continuing through to the lower
walkway (with more nuts at that point to support it), but not to the
atrium floor below.  In the revised design, the same design of connection
was used between the upper rods and the upper walkway as on the lower
walkway, but this now had to support twice the weight.  Petroski does
not mention the moment between the upward and downward rod connections,
only the double force on the upward connection.

This is a matter of detail; both books are in substantial agreement.
(I've read both, though I don't remember that bit about the moment in
the Levy and Salvadori book.)


January 25, 1995