Science Channel: UC engineer explains demolition disaster

UC expert explains how Hopple Street overpass disaster occurred

Science Channel's popular show "Engineering Catastrophes" turned to a University of Cincinnati structural expert to explain how demolition of an overpass in 2015 caused a fatal accident on one of the nation's busiest highways.

Construction foreman Brandon Carl was killed when the Hopple Street overpass on I-75 collapsed during demolition.

UC College of Engineering and Applied Science associate professor Gian A. Rassati told Science Channel that the demolition destabilized the cantilever overpass bridge, causing the accident.

"During deconstruction of the bridge you need to make sure the rest of the structure remains stable. So by starting to remove the loads at one end, the bridge became lighter at that end. That end of the bridge started lifting up," said Rassati, who teaches in UC's Department of Civil and Architectural Engineering and Construction Management.

Construction crews that noticed the steel girders begin to lift installed anchor bolts to keep the span in place during demolition. But the span collapsed onto I-75, killing a construction worker and injuring a truck driver that crashed into the fallen span.

"With hindsight being what it is, they should have removed all the weight from the middle and then started working from both ends to maintain the symmetry of the forces as much as possible," Rassati said. "The biggest issue that caused the ultimate failure was starting from one end, causing a seesaw effect."

"Engineering Catastrophes" airs on Science Channel. 

Featured image at top: UC associate professor Gian Rassati talks to Science Channel for its show "Engineering Catastrophes." Photo/Science Channel