Trucks delivering sub-materials, dozers, graders and rollers prepare the road bed for what will be additional lanes of 35W northbound heading toward downtown Minneapolis.
After nearly three years of intense, heavy-duty road work, thousands of daily motorists are now enjoying some relief from construction congestion through South Minneapolis and its neighboring suburb Richfield. Road crews recently opened three of five new lanes along a 4 mi. (6.4 km) stretch of northbound I35W and TH62 Crosstown to traffic through the two cities.
For daily commuters, truckers and travelers the new lanes are a sure and visible sign of progress and a hint of better things to come. When construction is complete, a severe bottleneck and headache for motorists driving through this heavily traveled and key junction of two major, urban highways will have been eliminated.
To make this a reality, though, the 100,000 plus daily commuters, truckers and travelers will have endured three years of heavy road reconstruction. Up to this point, drivers have undoubtedly relied on their patience and collective cooperation to get them through the ramp closings, detours, full road closures and sometimes snail paced traffic through a dusty and noisy construction zone.
When completed later this fall, crash rates should go down, rush hour congestion will be greatly reduced, capacity will increase and the shared road pavement of the Crosstown highway and I35W will be eliminated.
The joint venture of Ames/Lunda/Shafer — all mid-western based companies — snagged the $288 million contract to rebuild the pair of roads and the commons area they both share at this urban interchange.
After years of planning and studies, a small army of road crews and their arsenal of heavy equipment mobilized in the fall of 2007 to begin removing tons of worn, out dated concrete and moving and removing thousands of yards of dirt throughout this urban stretch of pavement.
Though challenging and daunting to road construction crews and designers alike, and despite the draw on the local labor market, the project is on schedule and within budget, said Steve Barrett, MnDOT project manager and resident engineer.
“The construction has gone well. It’s on schedule and we’ve done what we can to keep it within budget,” said Barrett.
The nearly 50-year-old pair of highways was badly in need of a makeover. After years of carrying innumerable tons of vehicles in the harsh hot and cold climate of Minnesota, the roads were falling apart, required a huge boost in capacity and a drastic change in geometrics according to the MnDOT Web site.
Prior to construction, six lanes of north and southbound I35W traffic with an ADT of 96,000 doglegged and fed into a narrow, four lane east and westbound stretch of the TH62 Crosstown highway with an ADT of 59,000. The funneling of a major interstate into a smaller capacity trunk highway forced drivers to weave and jockey for position for their next exit or entry ramp.
The new geometrics will feature an additional lane in both directions along with a HOV lane for portions of I35W leading up to the commons area of the road. These additional lanes will create four through lanes for TH62 Crosstown traffic and four through lanes for I35W traffic through the commons area of the two highways.
As in most road projects, the goal to increase capacity and decrease congestion and accidents is always easy to state on paper yet very difficult to plan, design and construct.
Along with the challenge of coordinating thousands of feet of underground utility relocations, MnDOT designed the complex project to maintain two lanes of traffic in each direction while under construction, Barrett noted.
“It hasn’t been without its challenges, mainly working under traffic conditions and the phasing and coordination of switching traffic back and forth between existing, new and temporary lanes to accommodate paving operations,” Barrett explained.
Bridge and overpass work also played a critical part in the schedule because MnDOT had to close down various portions of the road over dozens of weekends to safely remove and rebuild these structures, Barrett added.
Working within tight right-of-way limits and the close proximity of heavy road construction and equipment near homes and businesses has also been challenging, Barrett remarked.
A wide variety of Manitowoc, Terex, American and P&H cranes raised bridges and walls. Hundreds of Caterpillar, Komatsu and Case backhoes sliced into the landscape, moving tons of material and grading miles of future traffic lanes.
And, heavy duty daily trucking operations have been on the move on this narrow stretch of urban landscape and competing for space with workers, equipment and drivers on an active and busy pair of highways.
Despite the tight right-of-way restrictions, working in and around heavy traffic and toiling under the sometimes gruesome extremes of the artic cold and tropical heat of a Minnesota climate, road crews have accomplished a great deal.
“All of the bridges are up except for one and grading and paving operations on the remaining lanes and at the east and west junction points of the project will continue this summer,” Barrett said.
Unique to this project and a first on a MnDOT road project are the six pre-cast segmental box girder bridges built for this project, Barrett noted.
“The concrete girders were casted off-site near Lunda’s Rosemount, Minnesota, office and delivered to the construction site,” Barrett said. “Once they were raised they were secured by post tensioned cables, similar to the new I35W bridge recently built.”
Designers decided to go with a pre-cast segmental box girder design for these bridges because of their required curvatures and spans, Barrett said.
Road crews also placed stainless steel dowel bars and poured high performance concrete for the pavement to add strength and life to the new pavement, Barrett added.
Besides the new and much more efficient geometrics of the commons area and added lane capacity, crews removed 20 old bridges and built 26 new bridges, raised thousands of square feet of noise and retaining walls, laid thousands of feet of sewer pipe and built a transit station on I35W at the 46th St. bridge overpass.
Designers also eliminated a major flood nuisance on a section of I35W. Located near Diamond Lake Road on the north side of the construction zone, flooding caused by heavy rain pouring down on this low area of the freeway had been a recurring problem. Runoff has been as high as window level on some vehicles and it shut down the underpass several times over the years, according to MnDOT documents, which cited a number of issues such as low storm capacity, high water levels in Diamond Lake and lack of inlet capacity as cause for the flooding.
As part of the storm sewer design for this portion of the road, MnDOT engineers raised its elevation and rerouted some storm water flows to alleviate the flooding problems.
Though there is still plenty of paving work to accomplish, MnDOT expects to open both roads to full traffic later this year.