Construction on a new interchange at the junction of Highway 7 and Wooddale Avenue in St. Louis Park, Minn., proceeded well through each of the three major phases of the project.
The Minnesota Department of Transportation and prime contractor Ames Construction. Inc. of Burnsville, Minn., took a stop lighted intersection in an increasingly congested area of the Twin Cities metro area and performed a grade separation at the intersection of Highway 7 and Wooddale Avenue. The new interchange will enhance safety and help traffic move more efficiently.
The project also included a new Wooddale Avenue bridge spanning Highway 7 and the ramps to and from Highway 7, retaining walls, realignment of the south frontage road and repavement of a portion of Highway 7 from about the Canadian Pacific Railroad Bridge at the west end to Highway 100 at the east end. The project also included the construction of a dry pond/storm water filtration pond located at the southwest corner of the interchange.
Highway 7 carries high traffic volumes as a principal arterial route, particularly due to congestion and delays on the nearby Highway 100, said Beanna Magee of the Minnesota Department of Transportation Metro District office in Roseville, Minn.
“During rush hours, traffic diverges from Highway 100 to use Highway 7 or Wooddale Avenue and this led to operational issues,” said Magee. “The intersection was operating at capacity and long queues of cars waiting at the traffic signals frequently could be seen during rush hours.”
About 36,000 vehicles use this portion of Highway 7 each day, while Wooddale carries another 10,000 vehicles each day.
An average of 46.5 seconds of delay per vehicle on Highway 7 was occurring during the morning and evening peak periods, Magee added.
The new interchange will accommodate future traffic growth projections that are expected in year 2030, and take into account that a potential light rail station could be constructed at Wooddale Avenue.
“In addition to congestion, the safety aspect was a large reason for the project need. The long lines of cars waiting at traffic signals [particularly at Wooddale Avenue, which backed up and blocked local streets as well as a rail crossing at times] combined with turning movement conflicts and other factors led to an average of 12 crashes per year from 2004 through 2006,” Magee said. “Wooddale Avenue is a frequently used roadway by pedestrians and bicyclists, and crossing eight lanes of traffic on Highway 7 was difficult. The new bridge over Highway 7 creates a much safer situation.”
The $19 million construction project began in the fall of 2009 with utility relocation. Funding for the project was made up of federal funds, including funds from the American Recovery and Reinvestment Act, and funds from the city of St. Louis Park.
“At the beginning there were some delays with moving utilities, such as gas lines and fiber optics,” said Blake Jablonski, project manager with Ames Construction Inc., the prime contractor for the project. “Once we overcame that we worked on an accelerated schedule during the summer and finished the project by Thanksgiving 2010.”
Work took place in an older section of St. Louis Park where water mains and power utilities have been in place for many years and created an unknown situation.
“The project went pretty well considering what was there to work with,” Jablonski said.
Work was suspended during the winter of 2009-2010 and resumed during the spring of 2010. Snow and cold in early 2010 caused work to be put on hold as did rain throughout the construction season.
“Weather is always accounted for to some extent, however, the new interchange actually opened to traffic last fall about a week ahead of schedule,” Magee said. “Overall the project went well.”
Traffic on Highway 7 was shifted to the north side of the corridor as extensive drainage work was done near the south frontage road and abutments and ramps of the new bridge were constructed at the south side of the interchange. Relocation of a large sanitary sewer (an inceptor sewer owned by Met council), took place, along with relocation of the south frontage road and construction of the south exit and entrance ramps and abutments for the new Wooddale Avenue Bridge. Work on this first stage began in 2009 and continued in the summer of 2010.
Later in 2010, between August and November, traffic on Highway 7 was shifted to the south side of the interchange as crews worked to complete the abutments and ramps on the north side of the interchange.
During this time, construction of the north exit and entrance ramps and abutments for the new bridge were completed. Completion of the bridge followed.
The new interchanged opened to traffic on Nov. 9, 2010, leaving the final median and landscaping work to be completed by June of 2011. In 2011 crews will finish up some miscellaneous work such as seeding and placing sod, Jablonski said. Confined spaces in the construction area made it difficult at times to provide adequate space for all the contractors. There were numerous segments working together to handle contaminated soil abatement, bridge work, cast in place retaining wall construction of 75,000 sq. ft. (6,967.7 m), sanitary storm sewer that required 7,500 lineal ft. (2,286 m) of pipe, and city water main work that required 6,700 lineal ft. (2,042 m) of pipe and 2,000 lineal ft. (609.6 m) of ductile iron water main pipe.
“The project contained a lot of aspects that as a company we try to work on,” Jablonski said.
“The biggest struggle between contractors occurred when the project was shifted to Stage 2 and traffic was moved to the westbound lane. Crews were working to remove contaminated soil and finish reclaiming the existing roadway to use in the base of the new roadway.
“All of that was occurring at the same time and was being driven by concrete work that was taking place on the north side. That had to be finished so the bridge overlay could take place.”
The 113-ft. (34.4 m) single span bridge required 45 concrete girders. The project required the use of numerous pieces of equipment to handle the various segments of the project. When placing the bridge beams, crews used a hydro-crane and had an American HC80 ton crawler sitting on the westbound lanes of Highway 7.
“We had full closure of Highway 7 and so we were able to pull trucks in under the bridge,” Jablonski said.
On the project, crews also used two American HC50 ton cranes, a Cat D6RXW dozer, a John Deere 650 dozer, a Cat 623 paddle wheel, a Cat 14m blade and a Lull 944-E 40 forklift.Crews hauled 16,824 tons (15,262.4 t) of aggregate base and another 27,460 tons (24,911.2 t) of asphalt paving. Overall, crews moved 316,913 cu. yds. (242,297.3 cu m) of materials.
Crews with Ames Construction encountered almost twice as much contaminated soil as was anticipated on the project. The plans required a bid on removal of 9,000 cu. yds. (6,881 cu m) but 16,000 cu. yds. (12,232.8 cu m) were actually removed using a Cat 345 excavator, a Cat 330 excavator, a Case 210 excavator and a Hitachi mini-excavator.
“The owner had a testing agency on site at all times and as we were excavating they were running DROs [digital readouts] and visual tests to make sure all the contaminated soil was dug up,” Jablonski said. “Everything that was removed was taken directly off site.”
Once the contaminated soil was removed the area had to be refilled with granular material. If the fill was in an area where the new roadway was to be placed it was vital that it was packed adequately. CEG
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