Increased traffic during the peak recreation times of the year has spurred the need to construct a four-lane, 9-mi. stretch of highway from Little Falls to Brainerd in central Minnesota. This area is a weekend recreation area for the Minneapolis/St. Paul metro area, which is just two and a half hours to the south.
Little Falls to Brainerd is Phase 3 of the Highway 371 project, which consists of all new construction, and was handled by prime contractor Bauerly Construction in Sauk Rapids, MN. Previously, and during construction, travel took place on Highway 76, which runs adjacent to the new highway.
During the summer, traffic is often bumper-to-bumper, often only 15 ft. apart, said Paul Koenig, project manager of Minnesota Department of Transportation (Mn/DOT). The average daily traffic count (ADT) for 2005 was approximately 13,600, which isn’t much of an increase from the 1996 ADT of 12,500, but the improvements will make travel safer, said Robin Elstad, office manager of Mn/DOT.
“This area was a high fatality area,” Koenig added.
The ADT usually increases 70 to 100 percent during recreation seasons –– through the summer until after Labor Day –– and then slows down only to pick up again during hunting and snowmobiling seasons.
Work on this phase of the project was scheduled for completion at the end of October 2005.
“This is when we [had] to have all four lanes and the interchanges up and running,” Koenig said.
Preliminary work for the project actually began in 1998 by creating a bypass bridge. The bypass was opened to traffic in August of 2000. The following year Mn/DOT constructed the Highway 371 interchange at its intersection with Business Highway 371, just south of Brainerd, which was opened in 2002.
Then in May of 2003, a 14-mi. stretch of four-lane expansion of Highway 371, between the Brainerd bypass and Morrison County Road 48, took place; new northbound lanes were constructed east of the existing Highway 371, which was reconditioned to carry two lanes of southbound traffic. This segment was completed in 2004.
Rain occurred throughout June of this past summer, but instead of hampering construction it actually worked in the contractor’s favor. The Little Falls/Brainerd region has granular soil, creating excellent drainage, so work could continue.
Mathiowetz Construction Company, prime grading contractor in Sleepy Eye, MN, had to shut down other jobs around the state because of wet soil conditions and so was able to pull equipment from those jobs for use on the Highway 371 project, said Koenig.
“There are not a lot of contractors who have enough equipment to move that much dirt,” he said.
Mathiowetz was able to move 2 million cu. yds. of soil in six weeks, using 1937 and 1936 scrapers. Other equipment used on the project includes twin-engine 627 and 637 scrapers because of their mobility and ability to move 25 to 30 cu. yds. in each load.
D4 and D9 dozers were used, along with backhoes and cranes for bridgework. A 200-ton crane was used to set the bridge beams.
“We were right where we thought we should be by Labor Day,” Koenig said.
Two traffic movements took place later: southbound lanes were opened a week later with the exception of the last 1.5 mi. on the southern end of the project. At Highway 46, traffic was diverted to the existing Highway 76, so contractors could finish that stretch without traffic interruptions.
Materials
Approximately 160,000 tons of bituminous and 200,000 cu. yds. of gravel were required for the project. The hauling route had to be detoured for a while because a Bald Eagle’s babies hatched and so hauling was prohibited by the Department of Natural Recourses on one of the gravel roads because of the dust. Travel was detoured to another route until June 1 when hauling was allowed to continue.
Once the project ends, haul roads should be restored to their original condition, making sure widened corners and roads are reduced back to their original state.
Excavated borrow was used on the project wherever possible, but soil borings showed that some areas did not contain granular soil and so had to be removed.
“Some of these were found too late in the project to be used and so had to be removed,” Koenig explained. “It totaled about 100,000 cubic yards.”
Approximately 75,000 cu. yds. of soil was replaced with excess material from another portion of the project.
The type of road base dictates the type of surface that is used, so some portions of the project are concrete, which is usually placed over silt and clay subgrades, while the majority is bituminous, which is used with sand.
To form the base, a 1-ft. subcut was excavated and blended in place and replaced; the 7-in. gravel base was then placed, followed by the 6-in. of bituminous. Only 4 in. of gravel is actually needed but extra is placed to allow for the few inches that packs into the subcut.
Creating bituminous has turned into type of science all its own. In the past, one type of aggregate was mixed with oil to create the bituminous.
Now, there are several splits of the rock and the proper mix is created with the use of computers. Recycled roadbase also is added to the mix.
Koenig said that approximately 20 percent-recycled material, which is approximately the maximum that can be added, is used by Mn/DOT. Using the recycled material also creates a cost saving because less material has to be purchased and hauled.
The plant at the Highway 371 project was capable of creating 6,000 to 7,000 tons of bituminous each day.
“Mathiowetz does all our borrow pits and can check soil specifications on the job,” which speeds up the process, Koenig said. “We drafted 29 agreements for this project, none of which were major. Overall the project has gone well.”
The head inspector has six inspectors under him to ensure the project is running smoothly and to make some on-the-spot decisions. Koenig visits the job site every other day.
Deep ditches were created along side the highway for water retention and for snow storage in the winter, Koenig said.
“The borrow areas for the contractor turned into wetlands. To handle storm water along the new expressway, three runs of box culverts were placed,” he said. “The runs totaled 14 feet by eight feet, 14 feet by 12 feet, and 16 feet by seven feet. Fletcher Creek, where two of the box culverts were placed, can see four to six feet of water after a rain.”
The storm mitigation ponds overflow to Fletcher Creek and from there, overflow makes its way to the Mississippi River.
Costs
The total cost of the bridges constitutes approximately $6 million of the total project cost of $15.8 million. The original estimate of the project was $20 million, but the low bid reflected the efficiency created on the large project.
The Highway 371 expressway is part of 12 projects that were accelerated thanks to a $900-million Transportation Finance Bill passed in 2003 by the Minnesota Legislature. Together, all 12 projects will save more than 65 years of construction delays and save $140 million in project inflation costs. Highway 371 was accelerated one year from its original construction timeframe.
Koenig explained that planning for this project began in the 1970s, but in the 1980s the plans got dropped because there was no room in the budget. Then in the 1990s interest in the area, with its many lakes, boomed and the necessity for the improvements became real.
Elstad said that 80 percent of the project is funded Federally, while 20 percent comes from the state; it was the state’s 20 percent that was accelerated and will need to be paid back by the Department of Transportation district, starting in 2006. Koenig added that these payments have to come first, before new projects begin.
Two interchanges were also included in the project. County Road 46, on the south end of the project, was developed into a full interchange, as was County Road 115 on the northern end.
GPS
Aiding in the cost reduction is the incorporation of Global Positioning System (GPS) for surveying and excavation by both main contractors, Mathiowetz and Bauerly. Money is saved in reduced time in the field on surveying and in the number of blue tops that need to be set up.
Mathiowetz has been using GPS for three years, starting with private site work and is now expanding into highway construction to tolerance a road or stake a ditch.
“The unit we have on a blade tolarencing a road is not the same as doing staking, but it is same technology,” Dale Schweiss, estimator of Mathiowetz Construction, said.
Motorgrader Operator Kevin Hesse said the company formerly needed works to set up, take down and move the strings, with breaks in the mile and a half stretch of string to allow equipment to maneuver.
Now when staking a ditch and the top of a road, instead of pounding in a stake and running a string line, a worker has a computer screen he walks around with, and where ever he stands the GPS will tell if cutting or filling is needed, said Schweiss.
“Or we have a four wheeler we can move around with. The GPS can also be placed on a pickup or any piece of equipment,” he said.
Hesse added that on the finishing subgrade, a savings of approximately 30 percent is common, most of which is labor costs.
“It tells us where we are on the project and it can also automatically run the vertical movement of the blade,” Hesse said. “For an experienced operator it is easy to run. It is a little daunting at first, but it is fairly simple, even if you don’t have much computer knowledge.”
On the Highway 371 project, Mathiowetz met with Mn/DOT to find out what was needed by the contractors.
“Once they [Mn/DOT] gain a confidence in us, then we can space out the intervals in the blue tops,” Schweiss said.
Koenig added that there is a push within Mn/DOT to use machine control GPS and by next season it is hoped it will be incorporated on 50 percent of the agencies projects.
Global positioning has worked well for Mathiowetz on numerous projects, from a 200-acre development to a 20-unit development downtown, Schweiss said.
“It is quick to set up and load the files. Information is saved to a hand-held computer that is transferred to a larger computer and saved for future reference, in case the information is needed for an update on the project five years down the road,” he said. CEG
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