Willow Island Cooling Tower
Co l l apse Inves t i gat i on
On the morning of April 27, 1978, the jump form scaffolding collapsed at Cooling Tower No. 2 at the Monongahela Power Company station inWillow
Island, West Virginia. WJE was retained to determine the cause of the collapse, which killed fifty-one construction workers. The firm’s investigation
included an analysis of the jump form system and concrete maturity tests to recreate conditions at the time of the event.
The tragedy focused increased attention on the issue of concrete maturity, and led to heightened awareness and critical improvements in
the way early concrete strengths are specified and measured when early loading is anticipated. In the aftermath of the collapse, WJE was
retained to redesign the entire jump form scaffolding system used at Willow Island and numerous other cooling towers under construction
around the country.
Notes of Interest
• The tragic number of fatalities makes this the worst
construction accident in U.S. history.
• Dick Elstner was the principal investigator of the collapse,
with Don Pfeifer performing concrete maturity tests to
recreate the circumstances at the time of failure.
• A jump form system was used, with the forms secured by
bolts in one-day and three-day-old concrete. The framework
for the concrete forms also provided the framing and
support for the scaffolding platforms for the construction
crews. The forms were designed to be progressively moved
up the hyperbolic tower as it was built.
• The temperature had dropped to near freezing the night
before the collapse, which significantly retarded the rate
of strength gain in the recently placed concrete supporting
the jump form scaffolding. The cause of the collapse was
the imposition of construction loads on the shell before
the concrete of Lift 28 had gained adequate strength to
support these loads.
WJE 50 Years