Even with above normal rainfall slowing down construction, the South Dakota Department of Transportation is confident it will meet its fall deadline on the reconstruction of a 22-mi. (35.4 km) westbound stretch of Interstate 90 from the exit at Mt. Vernon to the exit at White Lake in southeast South Dakota.
As one of the oldest stretches of Interstate in the state, at 50 years old, it is in need of repair.
The project began May 5 with the removal of the existing westbound lane, which was crushed and used as a cushion under the concrete base, explained Laura Siefkes, human resources director with Upper Plains Contracting Inc., the prime contractor for the project. The existing gravel and asphalt was reused for the new project. Some of the asphalt was removed with a reclaimator and it is being used as recycled asphalt in the new asphalt shoulders. The existing asphalt mat will be reused as is and taken to hot mix plant to be incorporated with other new aggregate, creating a cost savings on the $22.5 million project.
The overall width of the new roadway will remain the same at 14 ft. (4.2 m); however, the concrete will be 2 ft. (.6 m) wider than it was on the existing roadway, now extending into the shoulders. The remainder of the shoulders will be asphalt.
Excavators were used to help remove the crushed concrete, while reclaimers were used to crush the existing surface. Skid loaders were used to help with the grading.
The subgrade was re-worked and compacted to specified density and moisture requirements. The depth of this work varied from 6 to 24 in. (15.2 to 60.9 cm) depending on the subgrade condition, explained Eric Prunty, engineering supervisor with the Mitchell area SD/DOT.
“There is a lot of work to do yet this year. Weather has been an issue. We’ve received more rain than usual, causing the project to fall a little behind. We would have liked to have started paving a little earlier, but we will still make the fall deadline,” Prunty said.
The weather also created some issues with the grade, making it difficult in some areas to get a stable grade, Prunty added.
“We have had to rework some areas and we have used some lime in some areas to help stabilize the grade. The lime helps dry up the existing dirt and material in the embankment,” he explained, allowing it to firm up.
Siefkes added, “We’re not missing any deadlines, but it is making it hard to make a consistent week. We’re working four or five days a week but we usually work six days a week.”
She said that Upper Plains Contracting Inc., has elected to make its portion of this project a one year endeavor, even though the final finish date of the overall project is mid-summer 2010.
Paving began around mid-August, though it was originally anticipated to begin July 20.
Other than the weather, Siefkes said a challenge for Upper Plains Contracting Inc., has been paving a 22-mi. (35.4 km) long section of Interstate.
“This project has the most miles we have ever let on a job,” she said. However, as an Interstate project, it is easier than an urban project because there are no crossovers like there are on country roads so once paving begins it goes smoothly.
The project also includes redoing the surface of the ramps at each end of the project. There are no bridge structures, however. The ramps will be paved with concrete, Prunty said. The existing concrete pavement was removed and replaced with new Portland Cement Concrete paving. Temporary ramps were constructed in order to keep ramps open during the construction process. They are adjacent to the existing ramps. Once the project is complete the temporary ramps will be removed, Prunty said.
For the concrete placement, dowel bar baskets were used. So, Upper Plains Contracting Inc., is using a dual dumper, requiring that a dump truck is backed up to the dumper and then a spreader and paver are used to placement, Siefkes said, rather than using an inserter to push them into the concrete.
“We haven’t used that process for two years,” she explained.
To aid in the timely completion of the project, a mobile concrete plant was moved to the project, Prunty says.
This 22-mi. westbound project is set for completion in 2010 so the hope is to have everything completed by this fall, however, some odds and ends may need to be taken care of during the 2010 season, Prunty said.
“We should be able to finish in the early to mid-2010 season.
The eastbound lanes of this 22-mi. section of Interstate are scheduled to be redone in 2011 and 2012. CEG
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