Knott Laboratory’s Forensic Engineers Reflect Upon Florida Bridge Collapse and Lessons from 1981 Hyatt Regency Walkway Collapse
Dr. Knott’s testing subsequently proved that the walkways were significantly under strength
Published March 28, 2018
By Stanley C. Stoll, M.Eng., P.E., CFEI, CVFI
On March 15, 2018, the 175-foot long pedestrian bridge in Miami, Florida collapsed on eight vehicles passing underneath the bridge. This was a terrible event where the cause cannot be speculated, but must be carefully examined. As such, we are not opining or speculating on the cause of the collapse. This is a reflection on lessons learned from a previous disaster.
On July 17, 1981, a large group amassed in the lobby of the Hyatt Regency in downtown Kansas City. The Hyatt was recently constructed and held Friday evening dances. At 7:05 pm, two walkways that hung from the ceiling collapsed. Emergency response personnel worked through the night to save those trapped beneath the tons of concrete and steel. And soon, everyone wanted to know what happened.
Dr. Albert Knott, founder of Knott Laboratory, was the test engineer hired to represent the steel fabricator during the subsequent investigation and litigation proceedings.
When the original structural drawings were drafted by the engineer and submitted for construction, the steel fabrication company drew up each connection and submitted those back to the structural engineer to make sure the intent had been met. In this case, the design engineer did not notice a minor change between the original drawings he submitted and the shop drawings the steel fabricator generated. The engineer approved the shop drawings and steel fabrication commenced. Dr. Knott’s testing subsequently proved that the walkways were significantly under strength due to this change that occurred during review of the shop drawings. The findings of this mistake changed nationally the way engineers take responsibility for checking shop drawings.
As it pertains to the Florida bridge collapse, the design and installation of a bridge such as this one requires collaboration of many entities. There are the design engineers, code officials, transportation officials, general contractors, sub-contractors, material suppliers and the list goes on. All entities play a role in the safe design and construction process. When time is of the essence and money is at stake, timelines get pushed and stress is substantial. This project is rumored to be behind schedule and over budget. As was the case with the Hyatt collapse, it was a very small detail that was missed, and it will likely be determined that a similar small detail was missed here in the high-stress construction process. Timelines and budgets are always going to affect a project, but it is paramount for engineers to be diligent in their design and review processes. We are tasked with protecting the public.