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Maintenance Facility
The winter of 1996 was a season for weather records around the country. People
everywhere were hard pressed to recall a winter that was quite as cold, dumped as much
snow, or hung on as long. Coupled with a fall season that left 70 percent above normal
rainfall, as well as an unseasonably cold spring, the winter weather left Kraus-Anderson
Construction Company with 5 to 7 feet of frost to thaw in May.
The North Division of the Minneapolis-based firm was constructing a
maintenance facility for Northwest Airlines Inc. in Duluth. The hangar, which covers
186,000 square feet of ground, services mid-size jets brought in from around the nation.
Work on the $26 million project began in May of 1995. While Project Superintendent Dave
Stolts planned to pour the concrete slab for the building in the winter, the frozen ground
shifted the crew to "plan B" - completing the overhead structure while working
off the frozen ground rather than a concrete slab.
The overhead work complicated frost removal even more by blocking out
the warmth of the sun and insulating the frozen ground. In addition, the wet fall created
extreme frost conditions. "We weren’t fighting frost," Stolts said.
"We were fighting ice." (According to Ground Heaters, Inc., this is true in all
thawing applications. Ground doesn’t freeze. Water in the ground freezes and turns to
ice, making it nearly impossible to excavate.)
In early March, Kraus-Anderson attempted to thaw the ground inside the
facility by constructing tents of poly to contain the heat and using approximately six
propane heaters in sizes up to 2 million BTU. Burning nearly $30,000 of fuel and removing
only 4 feet of frost in two weeks in a 10,000 square foot area, Stolts said the propane
heaters were slow and ineffective at penetrating the deep frost.
On May 13, Kraus-Anderson signed a contract to rent three E3000 Ground
Heaters through early June. Each Ground Heater was able to remove 5 feet of frost from a
6,000 square foot area for a total of 18,000 square feet per week.
"We were able to cut our thawing time by 2 weeks," Stolts
said. Kraus-Anderson estimated that it would have taken 3 months and $350,000 to $400,000
worth of propane fuel to accomplish what was done in 5 weeks with less than $35,000 worth
of rental expense and fuel for 3 Ground Heaters.
Stolts said the Ground Heater also provided greater accessibility by
allowing the crew to work in the area without the cumbersome hassles of plastic tents. In
addition, the Ground Heater offered greater efficiency over propane heaters, as well as a
better way to meet short deadlines. "Every bit of fuel we purchased was going
straight into thawing the ground," Stolts said. "We didn’t heat the air
around it and waste energy."
Stolts added that the Ground Heater could impact the way a company such
as Kraus-Anderson bids jobs by giving them a scheduling advantage. "A schedule is
everything," he said. "On projects like this, if we didn’t make our
schedule, we’d pay a $10,000 fine per day." In addition, the Ground Heater would
give them a bargaining tool in the actual bidding process. "If we tell an owner we
can complete a job in 12 months and another contractor submits a bid for the same amount
of money, saying they can finish in 14 months, which one do you think they will
choose?"
"The Ground Heater offers amazing advantages to contractors,
especially in the North," said Tim Schulke, project manager for Kraus-Anderson.
"It has vast potential!"
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Studies Page
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Dave Stolts
Project Superintendent,
Kraus-Anderson
Construction Company |
