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Culvert Replacement On the Ice Road Truckers Highway
"The collapsed area was on unstable soil and we had to build a swinging trench box door for worker safety to precut the multi plate ahead of the casing," Harr continued. "Progress was slowed by severe cold as temperatures dropped to 34 degrees below zero. The hammer was moved inside the 8 foot casing and warmed nightly by heaters with the eight foot pipe covered by a tarp." After the Silver Fox crew pushed the pipe past the edge of the roadway and beyond, the primary contractor decided to complete the remaining distance by open cut.
"Providing heat to the equipment and to the casing so it would not freeze to the soil meant running generators 24 hours a day, seven days a week," said Harr. "We had 200,000 BTU heaters blowing hot air into the casing to keep the hammer and the soil from getting too cold to move and operate. The darkness and the cold took a toll on us and the hours of work were shortened. The fifth wheels we stayed in soon also froze up and going to the bathroom became an issue. We used large plastic bags in the toilets, sealed them and let the bags freeze and disposed of them later."
Silver Fox's part of the project was completed in November.
Harr's trenchless culvert cleaning and pipe installation methods have drawn praise from the Alaska Department of Transportation.
"Bob Harr has proven to the State of Alaska that culverts of varying diameters and length may be placed under an active roadway, giving the state a valuable alternative option for the replacement of failing culverts, and the ability to add new culverts as need arises using trenchless methods," said Shawn Crites, project engineer, Alaska Department of Transportation and Public Facilities, Northern Region.
Crites said that if a culvert fails and is not able to be replaced, the roadway can be jeopardized. Using traditional trenched methods the roadway may have to be closed, or in cases where it is feasible to do half width construction, safety concerns come into play, and must be addressed with traffic control solutions.
“With the ever increasing environmental regulations,” he continued, “trenched methods produce another set of issues because of the amount of material that must be disturbed to replace a culvert. Culvert locations by nature are often near bodies of water. Much effort is required when using trenched methods to prevent the introduction of pollutants or sediment into these water bodies.