The Hyatt Regency Walkway Collapse
Introduction:
The Hyatt Regency Hotel was built in Kansas City in 1978. A state of the art building
with a 40 story hotel tower and conference facilities. These two components were
connected by an open atrium which was
15 metres high. Within this atrium there
were three suspended walkways connected
the hotel and conference facilities. In July
1981 approximately 2000 people were
gathered in the lobby to watch a dance
contest. A large crack was heard and the
second and fourth floor walkways
collapsed onto the lobby. This was the
worst structural disaster in American
history claiming the lives of 114 people
and leaving a further 200 injured.
Figure 1.
The Proposed Design:
Gillum-Colaco International (GCE) was hired to design all structural engineering
components of the building including the walkways. The original design was to have
the walkway supported by two wide flange beams, one on each side. This was then
hung from a box beam. Each box beam was supported by a washer and nut which was
threaded onto the supporting rod. This type of connection had virtually no moment so
the connection was modelled as a hinge.
Figure 2.
The Actual Design:
Due to a dispute between GCE and Havens, who were the contractors hired to
fabricate and erect the atrium steel, the design was changed from Fig 2 to Fig 3. This
was a double hanger rod connection to the box beam. The change in design was
implemented because Havens did not want to have to thread the entire rod in order to
fit the washer and nut. Each support rod of the fourth floor walkway was attached to
the atriums cross beams and threaded as shown in Fig 3. The second rod was 100mm
away and supported the second floor walkway.
Figure 3.
Failure:
The design failed because of the addition of an extra supporting rod. The extra rod
increased the load on the fourth floor nut from 90 kN to 181 kN. The box beams were
longitudinally welded as had originally been proposed. Because of this they could not
hold the weight of the two walkways. During the collapse, the box beam split and the
support rods pulled through them resulting in the fourth and second level walkways
falling to the ground level.
Who’s Responsible?
The major problem with the Hyatt Regency disaster
was a lack of clear communication between GCE and
Havens. This was particularly prevalent in the drawings
that were prepared by GCE. Havens understood these
to be final drawings and used them to create the
components of the walkways. These were actually only
preliminary sketches. Another large error was the fact
that there was no final review of the design by GCE
which would have allowed them to notice the extra
loading on the rods.
Figure 4.
As a result of these errors all the GCE engineers who signed off on the walkway
design lost their engineering licences in the states of Texas and Missouri. GCE also
lost the right to be an engineering firm.
Conclusions:
An engineer has a responsibility to their company and more importantly to the public
to ensure that they take all reasonable steps to ensure their design is sound. In the case
of the Hyatt Regency walkway collapse the engineers did not undertake a sufficient
review of the design of the rod/ box beam connection and this led to a large loss of
life. As a result of this case engineers became fully responsible for design projects in
the US due to the adoption of a report on the matter by the American Society of Civil
Engineering. This case highlights the need to review thoroughly all design
modifications during the construction phase of any project. Disasters such as are a
reminder of how an error in judgement can lead to catastrophe.
Group 3:
Ian Thompson
Laura Devane
David Martin
Stephen Conlon