I am showing this to my class this week. Due to a bad engineering detail a large number of people were killed when a walkway collapsed during a dance party.
On July 17, 1981, 113 people were killed and 186 injured when two suspended walkways collapsed in the Hyatt Regency Hotel in Kansas City.
This was the most devastating structural collapse in U.S. history-an accident that could have been prevented if a better-coordinated engineering review had taken place in the shop drawing process.
The original design specified six single forty-six-foot rods to run from the ceiling through the fourth-floor box beams and on through the second-floor box beams. During the course of construction, shop drawings were prepared by the steel fabricator suggesting that a set of two hanger rods replace the single hanger rod on the second- and fourth-floor walkways.
This change transferred all of the second floor load to the fourth-floor box beam, doubling the load transmitted through the fourth-floor box beam to the upper hanger rod.
This submittal was stamped by the architect, the structural engineer, and the contractor, indicating their review.
This is the modification that caused the doubling of the load to the connection.
And this is what the scene looked like that day.
A good video overview of the tradegy, Part 1 and 2 by R. Teshia.