Wet dirt could make it difficult and costly for contractors to meet a December deadline to rebuild a segment of Interstate-94.
The contract for the I-94 reconstruction in Milwaukee County between College and Howard avenues is out for bid with a quality-management plan requirement.
Such requirements pop up on some Wisconsin Department of Transportation contracts.
WisDOT officials did not return calls seeking additional information about the plans.
The quality-management plans force contractors to test the moisture of dirt in the road subgrade, which is the compacted earth on which contractors lay highway pavement. When the plan is required, contractors must be sure the soil is neither too wet nor too dry.
Striking that balance on the I-94 project timeline will be difficult because the schedule is driving the job, said Jim Hoffman, president of Black River Falls-based Hoffman Construction Co., which likely will bid on the job.
“Was this the right project to use QMP?” he said. “There are better projects to use QMP.”
The quality-management plan demands earth be compacted to a certain density, which forces builders to carefully control the dirt’s moisture.
The preferred method of drying the fill is to till it up and let it bake in the sun, said Tim Peterson, vice president of James Peterson Sons Inc., a Medford-based company that will bid the I-94 job as a subcontractor.
“Depending on how wet it is, like a clay or a silt, if they are way wetter than optimum, it may take a day or two or three to get it to optimum,” he said.
That could create problems on the latest I-94 project for which bids are due Jan. 20. The project is scheduled for completion by the end of 2010. The schedule requires builders to perform excavation and subgrade work between February and May, which are not necessarily the best months to be drying dirt in Wisconsin.
“Your days aren’t long enough, and it isn’t hot enough to dry it,” said Jack Arseneau, executive director of the Wisconsin Earth Movers Association Inc.
WisDOT has been using the subgrade requirements on and off since the early 1990s, Arseneau said.
The subgrade rules, according to WisDOT documents, will remain in the contract and may require additional efforts from contractors.
The quality-management plans are part of a broader set of national standards for materials used to build highways, said Greg Schmidt, president of GeoTest Inc., a West Allis company that tests soil moisture content and has worked on other segments of the I-94 reconstruction. Schmidt said he hasn’t seen studies analyzing the costs and benefits of the practice, but said standards for stability and quality are always important.
“It does provide complications with scheduling,” Schmidt said, “but every project does. On quick-turn projects, everything affects scheduling. To say it’s detrimental, I would say no, it’s not detrimental. It just creates issues with schedules.”
When there is not enough time to let existing soils on site dry in the open air, contractors must consider excavating and removing more material and trucking in new fill that meets moisture standards, Peterson said. The costs of buying, shipping and placing the fill varies depending on the types of new material being brought in and the location of the work, he said.
“They’ve got such a tight timeframe, a contractor has to really analyze the job at the time of bid,” Peterson said, “and price it accordingly.”