The Kansas City Hyatt Regency Walkway Collapse

“The Worst Structural Disaster In the United States”

The Kansas City Hyatt Regency Walkway Collapse

Dawn Williams – BackgroundTimmy Velander – DesignMike Tillges – Walkway CollapseAndy Ungerman – Reasons for Failure Ben Volkmann – Other FactorsBrad Tucker – Effects

Background Of Walkway

July 1980 – Most Modern Hotel in Kansas City finished. Consisted of 3 Buildings, 2 were connected by 3 walkways.

Walkway’s Original Design

•Box beams as intermediate supports

•One hole at both ends of Flanges

•Threaded single rod

-Hanger for 2nd and 4th floor walkways (3rd floor walkway was separate entity)

Walkway as Constructed

•4th floor box beams:

-Ends had 2 holes

-Outer hole connected to ceiling

-2 lower rods went through inner holes to support second floor walkway

July 17, 1981

7:05pm, July 17, 1981 2nd and 4th floor walkways collapsed.

Atrium filled with 1600 people during party2nd and 4th floor walkway dropped from hangers114 killed, 200 injured

Why did this fail?

Original Design As Constructed

Reason for Failure

Original design: Box beams of 4th floor walkway

designed to only carry the load of itself

As constructed: Box beam of 4th floor carried load of

itself and 2nd floor

Other Factors

Resonating vibrations from dancing and music Greatly increased stress on box beams.

Kansas City Building Code required for walkway: 100lbs/ft2 or 72,000 lbs for each walkway

Actual load day of tragedy 9450 lbs (63 people @150lbs each)

Design Lacked Redundancy

Effects

114 killed, 200 injuredLawsuits tallied more that $ 3 billionOriginal design did not meet code, but might not have collapsedFault found with design engineers Didn’t notice essential difference in 2

designs Licenses revoked in Missouri

“It wasn’t a matter of doing something wrong, they just never did it at all. Nobody ever did any calculations…. It got built without anybody figuring out if it would be strong enough.”

Patrick McLarny, attorney representing state of MO.