Source: http://enr.construction.com, May 12, 2015
By: Nick Zeman
The failure in March of a geosynthetically reinforced runway extension at Charleston, W.Va.’s Yeager International Airport has triggered a lengthy dispute among the airport’s insurance carrier, AIG Aero, the designer Triad Engineering and contractor Cast and Baker over the liability for damages, currently estimated at $16 million to $26 million.
“It’s been 55 days since the incident, and we have yet to see an adjuster from any party here at the site,” Michael Plante, Yeager airport spokesman, said on May 12.
At a special airport board meeting this month, Plante said Yeager refinanced its debt and began to settle claims from displaced residents because of delays in negotiations between the insurance companies representing the airport and its contractors. “AIG has told us that the airport is not at fault, and we like hearing that, but we want the community made whole,” Plante said.
At least one contractor, SE Clearing and Hydroseeding, was hired to perform recovery work on the condition they would be paid when the insurance is settled, Plante told ENR.
Hailed as a geotechnical marvel of modern engineering—the highest geotechnically reinforced slope in the U.S.—upon completion in 2008, it collapsed on March 12, forcing the evacuation of over 100 residents. Several homes down slope were destroyed and a creek flooded.
Tencate, a leading global geosynthetic materials company that supplied a specialized mesh for the $25-million project, said the runway apron won an Award of Excellence in the geosynthetic projects category of the 2007 International Achievement Awards from Industrial Fabrics Association International.
Christine Gerard, IFAI, said the competition is judged by industry experts on creativity, function, design uniqueness and complexity.
It proved its efficacy in 2010, when the runway extension was credited with saving 34 people after a plane over ran the runway on an aborted takeoff.
Completed in 1947, Yeager is sited on a man-made plateau atop rugged, mountainous terrain. New Federal Aviation Administration regulations in the early 2000s, however, threatened Yeager’s continued operation.
Required improvements included adding 500 ft of emergency-stop apron for Runway 5, which meant working on a mountainside that slopes down steeply more than 300 ft to the Elk and Kanawha rivers.
“The entire slope did not fail,” Plante says. The next steps are to deal with the collapsed slope and issue a request for qualifications to hire a contractor to restore the extension to a capacity that meets FAA regulations, he said.
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“I do believe the failure of this slope will have a major impact on the future of geotechnical engineering,” Koerner says. “It will cause designers to be much more conservative in their consideration of drainage and other hydraulic factors, which appear, at this point, to be the cause of the failure. It’s been distressed. They’ve known for sometime it was distressed.”
“We received two to three inches of rain in the days before the collapse, and a state of emergency for flooding was declared by the governor,” Plante says. The airport does not know if that contributed to it, but there was a significant weather event at the time.
Rick Valentine, Triad’s consultant, told ENR he could not share any of the findings from his investigation into the cause of the slip.
Fine-grain soil products available as fill material on similar projects also will receive more scrutiny from designers in the future, Koerner says. The slope was filled with 1.5 million cu yards of dirt, Tencate says.
John Lustombo, Tencate, said stormwater detention was not part of the company’s work on Yeager airport.
Triad Engineering and Cast and Baker did not return ENR’s request for comment.