The Ohio Dept. of Transportation had required an engineered demolition plan for the Hopple St. Ramp bridge that collapsed Jan. 19 onto Interstate 75 in Cincinnati, killing a worker, according to the contractor Kokosing.
Kokosing released Feb. 6 documents detailing its engineer-stamped demolition plan, noting that it chose an alternative approach that reduced the weight of equipment and machinery loads on the overpass by 25,000 lb.
The sequence of steel beam removal had been verified in terms of structural adequacy and stress levels, Kokosing Construction Co. said in a press release.
Industry experts had speculated on the issues of adequate engineering documentation or weight of construction equipment on the Interstate 75 overpass. During demolition, the middle span fell onto I-75 and killed a worker.
An industry expert had suggested that adequate engineering documentation before the demolition of the overpass might have prevented the accident, in which the middle span fell onto I-75 and killed a worker.
Linwood "Woody" Howell, an engineer with XR Structural, which inspects bridges for the Texas Dept. of Transportation, says a close look at the photos seems to indicate the structure was a cantilevered continuous bridge, with two side spans cantilevering out to support the middle span over the highway. “Any engineer looking at the structure would have known about this structure type where you can't take the side spans out before the middle span."
But Kokosing’s assistant vice president for heavy highway John Householder says the demolition was in accordance with ODOT requirements and stamped by two professional engineers.
“The cause of the incident is under investigation and we are cooperating closely with [the Occupational Safety and Health Administration, ODOT and our own experts to determine the cause,” he adds.
Another industry insider, a structural engineer and architect currently teaching at University of Cincinnati (25 years), speculated that construction loading may have played a role.