The Collapse of the Kansas City Hyatt Walkway

Management responsibility is ultimately not delegable.


On July 17, 1981, nearly one year after its completion, the Hyatt Regency Hotel in Kansas City, Missouri filled its lobby with guests participating in and watching the evening “tea dance.”


Suspended above the lobby were concrete walkways designed to connect both sides of the 2nd, 3rd, and 4th floors.


Shortly into the dance, two of the walkways, packed with spectators, collapsed onto the crowded atrium floor below.


The event was triggered by a failure in the connection between a supporting rod and the box beam of the fourth floor walkway.


The disaster killed 114 people and injured approximately 200 more, which at the time was the deadliest structural collapse in U.S. history.


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The owner of the project was Crown Center Redevelopment, but primary responsibility for the overall design and construction of the hotel rested on the shoulders of PBNDML Architects as the project manager.


The project was divided into three aspects: design team, construction team, and a safety inspection team.


PBNDML subcontracted the structural engineering and primary design responsibilities to G.C.E. International, including the roles of the project engineer and the senior project designer.


On the construction side of the project, the fabrication and erection of the atrium and steel cable construction, including the walkways, was subcontracted to Havens Steel Co.


In addition, Crown Center Redevelopment hired an independent safety inspection team, including an investigating engineer.


Design Changes


In order to implement the primary structural drawings, the fabricator, Havens Steel, would have had to thread the entirety of the steel rods below the 4th floor in order to screw on the nuts to hold the 2nd floor walkway in place.


To simplify the process, Havens altered the design to a two-rod system, where the rods from the 2nd floor would attach separately to the 4th floor beams, and the 4th floor rods would attach to the same beams and connect to the roof.


This change was intended to make fabrication and connection of the steel rods easier and faster. However, this essentially doubled the load on the 4th floor walkway beams, as these beams now supported the 2nd floor walkway as well.


In effect, this design change resulted in a new load path which introduced a compounding shear stress element to the 4th floor walkway box beam.


An investigation by the National Bureau of Standards (NBS) after the incident determined that the proximate cause of the collapse was a failure of the walkway box beam at a support rod connection.


Inadequate Design Verification Process

G.C.E., the structural engineering design contractor, created only a partial design and left the most safety critical design decisions to the fabrication/installation contractor, Havens Steel.

Havens created the design without any documented engineering analysis and submitted it to G.C.E., who approved the design, without any documented engineering analysis either.


NBS investigators were unable to find any significant recorded calculations of safety factors or yield strengths of the walkway connections.


Lack of Accountability and Oversight


All parties involved had a responsibility to identify and recognize the walkway as a safety-critical suspended load, which warranted special consideration and care.


During construction in 1979, the atrium roof had collapsed, prompting G.C.E. to ask Crown Center Redevelopment for an on-site inspection of the entire site.


Three different requests were denied due to the additional costs.


Clear delineation of accountability was absent with shared design responsibilities, numerous contractors and sub-contractors, and overlapping design verification processes.


PBNDML failed to exercise oversight of support contractors.


And the Kansas City Division of Public Works Department failed to provide adequate oversight and evaluation of design documents when it approved of the original design, which NBS investigators said violated the building codes even before the design change.


Poor Communication


G.C.E. management failed to retain safety-critical design information when two key structural engineers, involved in preliminary design activities, left the company.


The senior project designer and project engineer, both of whom had an exceptional knowledge of the design, left G.C.E. midway through the design process.


The switch to the alternate design of the walkway support structure was never fully communicated to the new G.C.E. design engineers, and the downgrade in structural integrity went unnoticed.


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A grand jury investigation into the collapse found no criminal actions linked to the accident.


Nonetheless, after two years of civil suits involving all parties totaling more than $100 million, G.C.E. International Inc. had its license revoked.


In addition, the two lead structural engineers working for G.C.E. were found guilty of gross negligence, misconduct, and unprofessional conduct in the practice of engineering.


The board of the American Society of Civil Engineers finally placed the accountability for this disaster on the G.C.E. engineers and defined the necessity of determining individual roles in overlapping responsibilities.


It reinforced the need for requirements ownership, requirements clarity, and requirements change control.


Ambiguity associated with overlapping responsibilities, matrixed support relationships, and complex supply chains must be overcome by implementation of rigorous configuration management with formal requirement change boards that include independent engineering and assurance representation.


Finally, it noted that it is important to consider how big projects can and do fail when small details are overlooked.


The collapse was a single system failure within the context of a 750-room hotel project, which one could reasonably assume included innumerable safety-critical design details and decisions.


The sheer magnitude of the undertaking further underscores the need for disciplined design build processes that include appropriate independent reviewers to ensure that every single safety-critical detail is addressed with rigor and care.


The American Society of Civil Engineers concluded by observing that it must be remembered that responsibility is ultimately not delegable.