SEOUL — Community residents may have stumbled across an odd sight at Kunsan Air Base: contractors tearing down recently built ammunition igloos.
It turns out soil underneath the $9.4 million project is much “softer” than Army Corps of Engineers designers expected, they said, because the base is built on reclaimed land.
In September 2001, after Lotte Engineering and Construction, a local contractor, began work on about 20 of the 30 igloos — flat-roof, concrete structures reinforced on two sides with earth — engineers noticed hairline cracks in the concrete bases, said Allen Chin, the Corps’ project management division chief.
The problem stemmed from a mathematical error used to estimate how much the soil would sink based on the igloos’ weight.
After construction was stopped, Chin said, the Corps brought in engineers from Pacific Air Forces to analyze the soil. Data was sent to the University of California at Berkeley in hopes of finding the best solution.
The answer, Chin said, was to drive piles – long, concrete supports that push down to the bedrock — and elevate the structure.
“It was obvious that’s the way we should have gone,” Chin said.
The $9.4 million contract was awarded almost a year earlier as part of a fiscal 2000 supplement grant for military construction projects in South Korea, Chin said.
Adding piles to the project cost an additional $7 million, said Chin. If they had been included in the original plan, it could have been about 50 percent to 60 percent less expensive, depending on what the contractors bid.
The project stalled for almost a year while planners waited for extra funding, which must be requested from Congress if a project exceeds its estimated cost by 20 percent, Chin said.
Congress gave approval in December; construction – or rather, destruction – began in January.
The contractor said it was the same amount of work to remove the old concrete slabs, put in piles and then build the walls again, so the contractor offered just to redo everything, Chin said.
The Air Force also requested a change in the door design, which will be reflected in the final project. It should all be completed by August 2004.
The soil error was really an aberration, officials said, as the Corps deals with hundreds of projects every year.
“This is for lack of a better term, an anomaly,” Schiavoni said.