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CROSS Topic Paper

Suspended access platform collapse - Chicago

Region: CROSS-UK Published: 1 December 2002


In 2002 a suspended access platform fell from the 100 storey John Hancock building in Chicago USA. Although no-one was on the platform at the time, three motorists were killed and several pedestrians injured as a result of flying debris.

This summary note is derived from a paper in (USA) Civil Engineering November 2006 pp52-59, authored by Alec S. Zimmer P.E. A.M.ASCE and Glenn R. Bell, SE., M.ASCE, which in turn was derived from a paper by the same authors at the 4th Forensic Conference, sponsored by ASCE’s Technical Council held in October 2006.

The paper gives a comprehensive explanation of the analysis which was carried out to determine the sequence of events, and of the conclusion that a number of components were under strength.

Note: this Topic Paper was published by SCOSS (Standing Committee on Structural Safety). Since March 2021, SCOSS is integrated under the name Collaborative Reporting for Safer Structures (CROSS).

Who should read this?

Structural and civil engineers involved with access to tall towers and buildings, temporary works engineers and access specialists.

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