A once bogged down interchange in a growing suburb of Minneapolis, Minn., now includes two 2-lane bridges that appear as one large bridge with a center median, to alleviate traffic issues and improve safety.
The bridges are located over Interstate 35E at County Road 14 in Lino Lakes, Minn. The project included three new traffic signals and turn lanes on County Road 14.
“We’re seeing some population growth in the suburbs and the existing intersection was not able to handle the traffic increases,” said Kent Barnard, communications director with the Minnesota Department of Transportation, the agency that oversaw this Anoka County project.
“The previous 4-way stop was bogging down the interchange. With the new signals vehicles can get on and off the interstate at this location much easier, eliminating the backups that used to take place,” said Charles Cadenhead, Anoka County construction engineer.
The bridge, which will carry two lanes of traffic in each direction versus the previous one lane in each direction, required about 64,000 lbs. (29,030 of reinforcement bar. An auxiliary entrance ramp and exit ramp over 35E were also added. “The entrance ramp was extended from County Road 14. It is now a long ramp to allow traffic to get up to speed when entering 35E,” Barnard said.
The $12.3 million project began in June of 2010 with pipe extraction and was in full swing by spring. The completed project, however, came in at a lower cost of $10.7 million.
Progress on the project progressed fairly well but wet weather last fall and this spring slowed things down a bit. However, crews with prime contractor Lunda Construction Co., of Black River Falls, Wis., were still able to complete the project on time. “Some of the soils we ran into weren’t what we expected. There was more clay and unsuitable materials than we expected, which made it difficult to work,” Cadenhead said.
The 250-ft. (76.2 m) bridges and about a half a mile of reconstruction of County Road 14 required about 270,000 cu. yds. (206,430 cu m) of common excavation, about 276,000 cu. yds. (211,017 cu m) of common embankment and about 72,000 cu. yds. 55,048 cu m) of granular embankment. Another 30,000 cu. yds. (22,937 cu m) of wet granular was needed for the road bed.
A second project, also on Country Road 14 in Anoka County, just a few miles west of the Lino Lakes Project, is located in Coon Rapids and Blaine and requires reconstructing a 3-mi. (4.8 km) length of two-lane rural roadway to a four-lane divided urban highway with turn lanes, traffic signals and curb and gutter.
The project will reconstruct Main Street/125th Avenue (CSAH 14) from east of Crane Street in Coon Rapids to west of Ulysses Street in Blaine. Planned improvements also include adding a raised median with curb and gutter, constructing a 10-ft. (3 m) wide pedestrian trail for the full length of the project on the south side of the roadway, constructing an overpass over the Burlington Northern Santa Fe (BNSF) rail line, and replacing traffic signals with five new traffic signals.
Increasing traffic spurred the need for this project. Highway 14 is the county’s only principal arterial road for east to west traffic to connect to Minnesota State Highway 10 and Trunk Highway 65. About 17,600 vehicles travel this stretch each day, with about 5 percent of that being heavy vehicles. By 2025 the traffic is expected to reach about 25,000 vehicles each day.
“We’re trying to accommodate the future needs of safety and capacity,” said Charles Cadenhead, Anoka County construction engineer. “So with this project we will have the right amount of traffic lanes and turn lanes and vehicle storage space at intersections.”
Anoka County, on the northern end of the Minneapolis/St. Paul Metro area, accepted the plans of C.S. McCrossin, of Maple Grove, Minn., in May 2011, which is a municipally led design build project, which has shortened the construction time frame by 5 years. Construction began in July 2011 and is expected to be completed in August 2012. “It’s nice from the county’s perspective that the contractor can use their efficiencies to the best of their abilities,” Cadenhead said. “Because it is a design build project we haven’t set any restrictions on how they stage it, other than we require certain roads in certain directions to be open, and we allow full closure at various times.”
As of mid-October crews were pouring curb and gutter in preparation of paving. Highway 14 was under full closure but once it was opened to traffic the project was closed down on the west end in order to work with some poor materials there, Cadenhead explains. Another stage of the project on the east end of Highway 14 is being constructed in halves. Traffic also was shifted to what is the westbound lane to the north side while reconstruction of the south side of Highway 14’s eastbound lane could occur.
Muck removal has complicated things a bit. The geo technical sub surface has some muck that is fairly deep and had to be replaced. Muck was removed and replaced with good granular fill and back filled using excavators and dozers. Select modified granular was hauled in from Elk River and Ham Lake, both also on the northern end of the Minneapolis/St. Paul Metro area. Bituminous came from McCrossins’ plant in nearby Maple Grove. The unexpected relocation of a major Quest Century fiber optic line slowed down construction, causing the project to fall slightly behind.
“Some of the risks within the job and with any job are utilities,” Cadenhead said. The fiber optic line runs through Anoka County and connects to cities further north so it couldn’t be relocated — it had to be shifted with construction. Crews were also working around three quarters of a mile of duct bank and so shifted the lines as much as the slack would allow.
“Making sure the line wasn’t cut was a major undertaking and a lot of work. It is difficult to get big equipment around that kind of utility issue and maintain progress,” Cadenhead said.
“Coordinating traffic in and out of the area with three nearby schools, Blaine High School, Roosevelt Middle School and Johnsville Elementary School, is a little bit of a task and takes some attention to see that things are done safely,” Cadenhead said. “At the high school there are younger drivers, and the other schools have a lot of traffic as students are dropped off and picked up, which we don’t normally see on projects. So it takes a little more attention to traffic that we wouldn’t see on non-urban road.”
The $35 million project also requires constructing an overpass over the BNSF Rail Road and new storm water runoff ponds. Fill will be hauled in for the overpass, and some large mechanically stabilized earth (mse) walls will be constructed. Some geo technical implementation will have to be done so crews can monitor the settlement in those areas.
“Anytime crews are working around a rail road things are more precarious,” Cadenhead said. “We have to be a little more careful, implementing the help of a flagger and the crossings have to be adhered to. That next segment will work on, involve about a mile stretch of roadway.”
Crews will work into December as long as the weather permits. CEG
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