1. HYATT REGENCY HOTEL WALKWAYS COLLAPSE ENGINEERING FAILURE By: Julee Christianson, Mike Cruz, and Katie Nolan

2. WHERE: Kansas City, MissouriDATE: July 17, 1981 3rd Floor Walkway Still Intact

3. Outline The Hotel and the Incident The Causes and the Problems Controversy and Conclusion References

4. People Involved • The owner - Crown Center Redevelopment Corporation • The fabricator - Havens Steel Company • The engineering design team - G.C.E. International, Inc. -Professional Consulting Firm of Structural Engineers -Previously known as Jack D. Gillum & Associates, Ltd. Main People involved in the Design – The Principals Jack D. Gillum, P.E.- structural engineering state licensed since February 26, 1968Daniel M. Duncan, P.E. - structural engineering state licensed since February 27, 1979

5. Who Agreed to What? • Crown entered into a standard contract with G.C.E. International, Inc. on April 4, 1978 • G.C.E. agreed to provide, "all structural engineering services for a 750-room hotel projected located at 2345 McGee Street, Kansas City, Missouri.” • In December 1978, Eldridge Construction Company, the general contractor on the Hyatt project, entered into a subcontract with Havens Steel Company Professional Fabricator, who agreed to fabricate and erect the atrium steel for the Hyatt project.

6. Hotel Features The hotel had a grand lobby which featured a multistory atrium crossed by three concrete walkways on the second, third and fourth floors The hotel advertised to have many parties and events

7. Tea-Dance Party Leads to Disaster A party was held in the lobby Over 2,000 people were in attendance People crowded the walkways and the lobby below to watch the dance competition The excess weight caused the fourth floor walkway to fall onto the second floor walkway and both walkways collapsed onto the crowded first floor The collapse left 114 dead and more than 200 injured This was the United States’ most devastating structural failure of the time

8. The Cause • The reason for the collapse was determined to be in the engineering design for the suspended walkways • The original box beam design (which was not actually used) did not meet the requirements of the Kansas City building code • However, the design that was used was even less safe than the original

9. Original Design Modified Design (was used) The 2nd and 4th floor walkways were originally supposed to be suspended from the same rod and held in place by nuts The fabricator had modified the design to use two hanging rods and the engineers approved the change without checking it On a preliminary design a note was made that the hanging rods needed to have strength of 413 MPa, but that note was left out on the final design and so the fabricator used hanger rods with only 248 MPa of strength

10. Design Problems • Havens proposed the modified design to simplify the assembly task and to eliminate the need to thread the entire length of the rods • However, the change in the design doubled the stress put forth on the nut which was under the fourth floor beam and with the change the nut had to support the weight of two walkways instead of just one • “The ultimate capacity actually available using the original connection detail would have been approximately 60% of that expected of a connection designed in accordance with AISC Specifications” according to the National Building Specifications

11. FAILURE – What Went Wrong? • The box beams resting on the supporting rod nuts and washers were deformed because of the stress that was exerted on them • The box beam resting on the nuts and washers on the rods could no longer hold up the load. • The box beams (and walkways) separated from the ceiling rods • The second and fourth floor walkways fell to the atrium first floor with the fourth floor walkway coming to rest on top of the second

12. THE HANGER ROD THREADS, WASHER AND SUPPORTING NUTNOTE: THE DEFORMATION IN THE WASHER CAUSED THE BEAM TO SLIP

13. Close-ups of some of the 4th Floor Beams

14. Interesting Findings • On October 14, 1979, part of the atrium roof collapsed while the hotel was under construction • On October 16, 1979, G.C.E.'s Gillum wrote the owner, stating that he was undertaking both an atrium collapse investigation as well as a thorough design check of all the members comprising the atrium roof. G.C.E. promised to check all steel connections in the structures, not just those found in the roof • Reports were sent to the owner assuring the overall safety of the entire atrium • Seeing that G.C.E. said the atrium was safe, the hotel was opened in July 1980 • The Hotel had only been in operation for about one year at the time of the collapse

15. Controversy After the change in the design, the Havens Steel Company claims that they informed G.C.E. International Inc. of the alteration, but the engineering firm denies ever receiving such a call for change approval However, Jack D. Gillum’s seal of approval was attached to the revised design drawings

16. Engineering Ethics • Daniel M. Duncan, Jack D. Gillum, and G.C.E. International, Inc., were charged by the Missouri Board of Architects, Professional Engineers and Land Surveyors of gross negligence, incompetence, misconduct and unprofessional conduct in thepractice of engineering in connection with their performance of engineering services in the design and construction of the Hyatt Regency Hotel…and later they were found guilty

17. In Conclusion The two structural engineers lost their Professional Engineering licenses and are no longer able to practice in the states of Missouri and Texas Both are now practicing in other states A number of firms were bankrupt Many expensive legal suits were settled out of court

18. References Harris Jr., Charles E., Michael S. Pritchard, and Michael J. Rabins. Engineering Ethics. Wadsworth, 1995. “Hyatt Regency Walkway Collapse.” Engineering.com. 13 Nov 2007. <http://www.engineering.com/ Library/ ArticlesPage/tabid/85/PageID/199/ArticleID/175/articleType/ArticleView/Defau lt.aspx>. Martin, Rachel. “Hyatt Regency Walkway Collapse.” 26 Nov 2007. <http://www.eng.uab.edu/cee/faculty/ndelatte/case_studies_project/Hyatt%20 Regency/hyatt.htm>. Texas A&M University. “Engineering Ethics”. 27 Nov 2007. <http://ethics.tamu.edu/ethics/ hyatt/hyatt1.htm>.