Hyatt Regency Walkway Collapse
The Hyatt Regency Hotel was built in Kansas City, Missouri in 1978. This
hotel consisted of a 40-story hotel tower and conference facilities, which
were connected by an open concept atrium. Inside the atrium, there were
three walkways that connected the hotel to the conference facilities on the
second, third, and fourth floors. The atrium was 145 feet long, 117 feet
wide and 50 feet high.
The project began in 1976 with Gillum-Colaco International Inc. (G.C.E.
Inc.) as the consulting structural engineering firm. They were contracted in
1978. The construction on the hotel began in the spring of 1978. In December
of 1978, Havens Steel Company entered the contract to fabricate and erect
the atrium. The following February, Havens changed the design of the
connection for the second and fourth floor walkways from a single to a
double rod. During construction in October 1979, part of the atrium roof
collapsed and an inspection team was brought in to investigate the collapse.
G.C.E. vowed to review all the steel connections in the atrium. In July
1980, the hotel was open for business. On July 17, 1981 at 7:05 p.m., a loud
crack was heard as the second and fourth floor walkways came crashing down
to the ground level. There were about 2000 people gathered in the atrium for
a dance contest. After the collapse, 114 people were dead and left more than
200 were injured.
Main Reasons for Collapse
The failure of the Hyatt Regency walkway was a combination of things. The
most important cause was the design in the walkways. The proposed design of
the walkways was:
Due to disputes between G.C.E. and Havens, the design changed from a single
to a double hanger rod, simply because Havens did not want to thread the
entire rod in order to install the washer and nut.
- A wide flange beams that was used on either side of the walkway which
hung from a box beam.
- A clip angle that was welded to the top of the box beam which
connected the flange beams with bolts.
- One end of the walkway was welded to a fixed plate, whereas the other
end was supported by a sliding bearing
- Each box beam of the walkway was supported by a washer and nut which
was threaded onto the supporting rod.
The actual design consisted of:
Due to the addition of another rod, the load on the nut connecting the
fourth floor segment was increased. The original load for each hangar rod
was to be 90kN, but the alteration increased the load to 181kN. The box
beams were welded horizontally and therefore could not hold the weight of
two walkways. During the collapse, the box beam split and the bottom rod
pulled through the box beam resulting in the collapse. Another problem was
the lack of communication between G.C.E. and Havens. The drawing prepared by
G.C.E. were only preliminary sketches that Havens interpreted to be the
finalized drawings. Another large error was G.C.E.'s failure to review the
final design which would have allowed them to catch the error in increasing
the load on the connections.
- One end of each support rod was attached to the atrium's roof cross
- The bottom end of the rod went through the box beam where a washer and
nut were threaded on
- The second rod was attached to the box beam four inches from the first
- Additional rods were suspended down to support the second level in a
Who's to Blame?
An investigation took place to determine the exact cause of the accident and
who was responsible for the accident. The investigation determined that the
flaw was contained in the design and the construction techniques were not at
fault.The construction was sound according to the imperfect design. G.C.E
was credited with the complete fault of the collapse of the walkways. These
conclusions were arrived at by conducting an extensive investigation of the
walkways. First, they determined how the walkways collapsed. The fourth
floor collapsed first, directly onto the second floor, which in turn caused
it to collapse. It was also determined that the design prints had been
changed with G.C.E. approval. The investigation found out that both designs
of the walkways were well below the required safety stress required by the
Kansas City Building Code. The engineers at G.C.E. were found of gross
negligence, misconduct and unprofessional conduct in the practice of
engineering. Consequently, the engineers lost their licenses and many
supporting firms went bankrupt. The results proved that engineers are held
responsible for the public's safety in the design of their projects and must
be held accountable if anything goes wrong.