Kansas City Hyatt Regency Hotel

Walkway Collapse

Background

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.

Timeline

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.

Ruins of the Walkway

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:

Proposed Design
  • 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.

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.

Actual Design

The actual design consisted of:

  • One end of each support rod was attached to the atrium's roof cross beams
  • 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 rod
  • Additional rods were suspended down to support the second level in a similar manner

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.

Torn Box Beam

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.

3rd Floor Walkway

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.

Side View of Ruins

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.

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