Why did the hyatt regency walkway collapse?
The Hyatt Regency Hotel walkway collapse in Kansas City on July 17, 1981, is one of the deadliest structural engineering failures in U.S. history (killing 114 people). The cause was a fatal design change during construction, compounded by a lack of proper oversight.
The Technical Failure: The original design called for single, continuous steel rods to run from the roof, through the 4th-floor walkway, and down to support the 2nd-floor walkway below it. This would have made both walkways hang from the roof.
The Deadly Change: During construction, the fabricator found the original design difficult to build and proposed a change (which the engineers approved without thorough analysis). The change used two separate, offset rods instead of one continuous rod. One set of rods held the 4th-floor walkway from the roof. A second, separate set of rods then hung the 2nd-floor walkway from the 4th-floor walkway.
Why It Collapsed: This change doubled the load on the connection box (nut/washer) at the 4th-floor walkway beam. On the night of the collapse, during a crowded tea dance, this critically overloaded connection failed, causing the 4th-floor walkway to fall onto the 2nd-floor walkway below, and both crashed into the atrium lobby.
It was a catastrophic failure of engineering ethics, communication, and review. The engineers lost their licenses, and it led to major reforms in engineering standards and construction oversight.
Detailed analysis from the ASCE: Lessons from the Hyatt Regency Collapse