Co l l apse Inves t i gat i on
On March 2, 1973, construction crews were placing concrete on the twenty-fourth floor of the Bailey’s Crossroads apartment building while shoring
posts were being removed beneath the concrete slabs at the twenty-second floor. The increase in load to the recently constructed twenty-second and
twenty-third floor slabs caused shear failures that triggered a sudden progressive collapse to ground level. The contractor retainedWJE to investigate the
cause of this tragic structural failure.
As lead investigator, Dick Elstner concluded that the shoring posts had been removed before the concrete slabs reached sufficient strength to
safely support the construction loads imposed from the floors above. The results of the investigation focused greater attention on early strength
issues, shoring and reshoring practices, and the profound consequences of progressive collapses.
Notes of Interest
• Progressive collapse is defined in the American Society
of Civil Engineers (ASCE) Standard 7-02, Minimum Design
Loads for Buildings and Other Structures, as the “spread of
an initial local failure from element to element, eventually
resulting in the collapse of an entire structure or a
disproportionately large part of it.”
• Unfortunately, the mistakes made at Bailey’s Crossroads
were repeated in 1981, leading to the progressive collapse
during construction of the Harbour Cay Condominium
building in Cocoa Beach, Florida. WJE investigated that
failure as well.
WJE 50 Years