The Hyatt Regency Collapse & the Founding of Knott Laboratory

On July 17, 1981, a large group amassed in the lobby of the newly constructed Hyatt Regency in downtown Kansas City. The hotel hosted a popular dance night each Friday. The Hyatt’s lobby featured four spectacular walkways that were suspended from the ceiling. These walkways were popular locations to take in the dancing and festivities below. At 7:05pm, two of the walkways collapsed, killing 114 and injuring an additional 216 people.

Kansas City Star story and photos from the scene.

Knott Laboratory’s founder, Dr. Albert Knott, was the test engineer retained to investigate the cause of the failure and represent the steel fabrication contractor in the subsequent litigation.

The structural engineering plans were developed by Jack D. Gillum & Associates for the project. These plans were provided to the steel supply company who drew up each connection and submitted those back to the structural engineer to make sure the intent had been met. In this case, the steel company had a concern about fabricating the walkway connections as designed. They said the whole rod would have to be threaded to hold the walkways in place. The threading could be easily damaged in installation, so they proposed hanging the second-floor walkway from the fourth-floor walkway via separate, offset rods. The design engineer did not notice the change between his original drawings and the new shop drawings generated by the steel fabricator. The engineer approved the shop drawings without running the proper calculations on this change and the steel fabrication commenced.

Dr. Knott’s testing proved that the walkways were significantly under strength due to this change. With dozens of people on the walkways, the box beams split and the suspension rods were pulled through, resulting in the total collapse.

The findings of this mistake led to national reform on how engineers take responsibility for checking shop drawings. This case is still taught today as a cautionary example in engineering schools across the country.

From his work on the Hyatt Regency case, Dr. Knott went on to found Knott Laboratory in 1982 and help pioneer the field of forensic engineering. It’s Dr. Knott’s exceptional drive for investigative excellence that still fuels the company today.