Road workers and their equipment will soon complete an ambitious project to rehabilitate a 10 mi. (16 km) stretch of I-35 leading into the core of Duluth, Minn., an upper Midwest tourist destination and major international shipping port. Much of the work was confined to a 4 mi. (6.4 km) stretch of the road and just over two mi. (3.2 km) of that segment became a total reconstruction of the highway.
I-35 stretches for nearly 1,600 mi. (2,560 km) between the sometimes arctic climate of northern Minnesota and the southern, more desert-like climate of Laredo, Texas.
Work on this most northern portion of I-35, dubbed the “Mega Project” by Minnesota Department of Transportation (MnDOT) engineers because it is making a variety of road and bridge improvements under one contract, began in May, 2010.
The joint venture of Arrowhead 35 Contractors formed between Lunda Construction and PCI Roads hooked the job with a low bid of $68 million.
Lunda Construction is based out of Black River Falls, Wis., and PCI Roads is located in St. Michael, Minn. Both companies have many years of experience between them in heavy bridge and road construction in the upper Midwest.
Along with the highway reconstruction, in just under two years, road and bridge crews have nearly completed reconstructing three critically fractured bridges — all over 1,000 ft. (305 m) long — removed several railroad bridges and made deck, rail and structural repairs on 40 other bridges.
For daily motorists and the thousands of visitors to Duluth, the road improvements will make the highway a safer road to drive. It will have wider shoulders, improved site distances and a new center median to replace a barrier that dramatically showed its age with exposed rebar and crumbling concrete, according to MnDOT officials.
Located at the western tip of Lake Superior, the city of Duluth is linked to the Atlantic Ocean through the Great Lakes and the St. Lawrence Seaway. Duluth and its twin, Superior, Wis., are America’s inner-most shipping ports.
Duluth also is the gateway to Lake Superior’s 150 mi. (240 km) long North Shore lined with state parks, rugged land, and idyllic sea shore communities. Roads heading north out of Duluth lead to the Boundary Waters Canoe Area and Superior National Forest filled with lakes, canoeing, fishing and hunting opportunities.
Visitors from around the upper Midwest and Canada also make Duluth a vacation destination. It hosts many arts and sporting events and is the home of Grandma’s Marathon, a major, international marathon.
The dramatic topography of Duluth, man-made obstacles, historical standards and an ADT that more than doubles on many weekends, made the design and construction of this project very challenging, said Roberta Dwyer, MnDOT pre-construction project manager.
The city of Duluth is hemmed in by Lake Superior, the largest of the Great Lakes to the east and an 800 ft. (244 m) bluff to the north and west. Add in an active rail line and another rail corridor on the list of historical structures and space can get tight, said Dwyer.
MnDOT, though, is applauding the traveling public, the contractor and Duluth’s citizens, businesses and community groups for making this project a winner. It is meeting its deadlines, coming in on budget and the Duluth drivers have been very patient and cooperative, Dwyer said.
“The construction has gone extremely well when you look at it from our stand point,” remarked Dwyer. “We’ve had an excellent contractor who has come in with lots of forces, who has been well organized and who has been truly dedicated to the project and they’ve really made this project a success.”
And, “likewise to the public who has been wonderful in using alternate routes and being patient with the ramp closures. It just could not have gone any better.”
MnDOT began an active public relations campaign about a year in advance of the project start date to begin informing Duluth residents, community groups and businesses of the upcoming construction.
“We did a lot of partnership with Visit Duluth, the Chamber and neighborhood groups to let everyone know what was going to happen,” Dwyer said.
“We also partnered with the Duluth Transit Authority to provide park and ride lots and free bus rides and that’s been extremely successful,” Dwyer explained. “It’s also very critical that businesses are informed because we are very much a tourist town. We wanted anyone who came into town with a hotel reservation to know what was going on. The business community has also been another great set of partners.”
Traffic control and management during the work has been an on-going game of coordinating lane and ramp closures and detour routes. The I-35 corridor in Duluth was very narrow before the improvements were made; forcing the road to close down to one lane each direction between the months of May and October over the last two years, said Dwyer.
Numbers also show that an ADT of 48,000 can swell to more than 100,000 during many weekends of the summer tourist season for this city of 84,000 and making the new road improvements a long awaited relief for the motoring public.
Traffic control on a three way interchange linking I-35, I-535 and TH53 affectionately known to MnDOT designers as the “Can of Worms” because of its inter-locking system of roads, ramps and highway splits was a puzzle on its own.
Though there was not any major reconstruction here, there was a series of overlays, railing improvements, painting, deck and structural repairs that required some strategic planning to manage lane and ramp closures at this interchange, Dwyer said.
“It is a very complex area to work in. We actually had a multi-staged matrix that showed what could be closed at what time, what could remain open and number of working days for each closure and detours for each of the closures,” Dwyer explained. “There are over 20 bridges in that complex so it was quite a feat to get these done.”
The repairs and reconstruction of this segment of 35 were long overdue according to the MnDOT Web site for this project. After 40 years of heavy traffic use and numerous bituminous overlays, this segment of freeway in Duluth required a high level of maintenance. The project received a jump start when the Minnesota State Legislature in 2008 passed funding to replace its fracture critical bridges after the I-35W bridge collapse.
Again from the Web site, what started out as a project to replace just less than 2 mi. (3.2 km) of concrete pavement grew to replace the three fracture critical bridges along with needed improvements to more than 40 other bridges, drainage systems, signing and lighting in this segment of the freeway.
“Building on the funding made available for the bridges, MnDOT was able to advance funds to create the Mega Project,” Dwyer further explained. “The Mega Project was able to address all the needs within the corridor under one project. This created huge efficiencies in construction and traffic handling. Rather than close lanes for multiple projects over many years, all this work was packaged into what was to be a two and a half year project.”
Added Dwyer, “it was very fortuitous that the funding for the bridges was made available at the same time.”
Along with the bridge reconstructions, improvements and new pavement, critical geometric improvements have also been made through this stretch of the Duluth I-35 corridor.
“When the interstate through Duluth was originally constructed, there were numerous rail lines crossing the interstate. Only one of these lines exists today. The unused rail bridges could be altered or removed to improve sight distances and construct full shoulders on I-35,” Dwyer said.
Before construction, Dwyer noted, “there were many places where we didn’t have full shoulders or no shoulders at all, especially on the bridges. Having these shoulders for safety is an incredible benefit”
On one of the fracture critical bridges, it was possible to lower the grade more than 7 ft. (2.1 m) because of one of the bridge removals, Dwyer said.
The project required pretty typical utility relocations. However, a 72 in. (183 cm) sanitary sewer pipe that captures sanitary sewage for Duluth and its surrounding communities required special attention, Dwyer noted.
“It was very shallow at that location because the pipe is near the lake and we have a high water table there. It sits on mucky, silty soil.” explained Dwyer. “We were concerned about the weight of additional fill required to bury the pipe. So a special structural slab mounted with footings was designed and built to be placed over that pipe for protection.”
Since work began in May 2010, hundreds of workers and dozens of pieces of heavy equipment have been toiling long hours to finish the job.
Terex and American cranes have hoisted tons of steel and concrete girders for the new bridges, including more than 470,000 lbs. (214,000 kg) of steel for one of the bridges alone and pounded nearly 85,000 ln. ft. (25,950 m) of piling into the ground.
Cat, Volvo and Hitachi backhoes have removed more than 210,000 cu. yds. (160,650 cu m) of common excavation including 31,000 lbs. (14,000 kg) of contaminated soil. Pavers have placed more than 131,000 cu. yds. (100,215 cu m) of concrete and workers tied into place nearly 2.2 nillion lbs. (1 million kg) of rebar.
A partial list of equipment working this project includes nine Terex, American and Grove cranes, four Volvo 460 backhoes, two Cat 345 backhoes with GPS, two Cat 330, one Cat 324 and a Hitachi 450 backhoe. GPS equipped Cat blades are on site along with GPS equipped Cat dozers.
Though the project is winding down, bridge and road crews are still very busy completing concrete pours on the remaining ramps, placing bituminous pavement, and installing the median barrier, quadrails, lighting, signing and striping.
MnDOT and the contractor will open the highway to full traffic by the end of October with minor bridge deck repairs, striping and installation of fiber optic cable to be completed in the spring of 2012. CEG
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