The fourth year of an eight-year project was checked off the list in 2003 with the construction of two bridges that are designed to add clearance and width to accommodate the 50,000 vehicles that travel the 2-mi. (3.2 km) span each day.
The plan included reconstructing the Main Avenue interchange from 25th Street to 45th Street, which is 1 mi. on each side of the Interstate 29 and Interstate 94 junction. This is a high-traffic area of Fargo, because the majority of the city’s shopping is located in the area.
Both bridges, the north and south bound sections of the I-29 overpass over I-94, were originally scheduled for demolition and reconstruction in 2004, but the timeline was moved up a year when a truck carrying a wind turbine struck the bridges during the spring 2002. Many of the beams in the existing bridges were repaired and filled with concrete to stabilize them until work could begin in 2003.
“Significant damage was done to the bridges,” said Kevin Gorder, project manager with ND/DOT in Fargo, ND, which designed and administered the project. The $7-million project included widening the existing roadway from two lanes to three in each direction and adding and creating more room under the bridges.
When replacing the existing concrete box beam bridges ND/DOT opted for steel girders.
“We went to the thin steel girders to create more clearance,” Gorder said. The bridges are also longer so more lanes can be added on I-29, up to four lanes in each direction if needed in the future.”
“When you drive under the bridges, the area is now wide enough to complete six lanes in the future,” Gorder said. “We’re getting close to the point where there will be enough traffic to warrant the six lanes.”
The entire bridge was rebuilt, using some of the existing piling where possible, and the decks were finished in concrete. “The bridges are wider than what was there since another lane was added,” said Jeremy Stigen, project manager with Wanzek Construction of Fargo, ND, prime contractor on the project. “It was pretty dangerous if you were traveling from the south heading north on Interstate 29 and wanted to merge with westbound traffic.”
“By putting in thinner piers and longer bridges, the addition on the bridge didn’t match the old bridge so we had to start from scratch,” Gorder said. “The roadway was finished in concrete, as well. The road portion was basically the length of the bridge so we realigned the loop ramp.”
Finishing two bridges in one construction season created some challenges. “We did all the bridge work on the two bridges. It was a very tight schedule to get two bridges done back to back,” Stigen said, “But they were done on time.”
To handle the heavy workload, a tremendous amount of overtime was needed A night crew was added so new girders could be installed at night and so demolition of the existing bridges could also be done at night. Night work lasted about eight weeks in all, Stigen said.
The work area was rather congested and so it was difficult to get a crane in the area that was large enough to handle the huge, heavy beams. “We had one crane in our fleet that would handle the weight of the existing beams,” Stigen says, adding that when the bridges were damaged and concrete was added to repair them, considerable weight was added to the beams, making it necessary to use an even larger crane.
About 1.25 in. (3 cm) of the existing surface of the I-94 roadway was ground off in preparation of refinishing. Dowel bars were placed in the roadway to keep the joints from shifting, which also made for a quieter roadway, a benefit for local residents. Resurfacing continued east a couple of miles to an area where sound walls were also installed in 2003, creating an added benefit to local residents.
Sound walls were installed along I-94 from 5th Street to University Avenue by Industrial Builders of Fargo, ND Concrete Inc., of Grand Forks, ND, supplied the precast concrete sections.
The total cost of the sound walls and their construction is $2.5 million; of which 90 percent comes from the federal government and 10 percent comes from the ND/DOT. Half of the decorative portion is being paid for by the city of Fargo.
Increased traffic
Increased traffic projections have spurred the many facets of this project. In 2002, $23.6 million was spent to reconstruct and widen southbound I-29 from 40th Avenue South to Main Avenue, which included finishing the underpass at 17th Avenue South and 9th Avenue South. The roadways for these two underpasses were also completed in 2002. The corresponding northbound portion of I-29 was completed in 2001. The 2002 portion of the project was the largest one-year project to date in North Dakota, which was finished one month ahead of schedule.
For 2004, two more bridges will be reconstructed at the Main Avenue Interchange over I-29, which is just north of the I-29/I-94 work that took place in 2003. Main Avenue between 25th Street and 45th Street will also be reconstructed. So far $22 million in bids have been awarded and contracts for another $8 million are yet to be bid, Gorder explains.
Strata Corporation is the prime contractor for the of the first two parts of the project, 36th Street to 45th Street and the bridge over I-29, with the project’s final bid opening covering 25th Street to 34th Street.
Traffic impacts are scheduled to begin as early as March 1, with Main Avenue reduced to one lane each direction with left-turn lanes where possible. In addition, five of the eight through lanes from 25th Street to 45th Street are expected to be closed by mid-March.
Preliminary work in preparation for the 2004 Main Avenue project has begun with Xcel Energy moving one of their eight-inch gas lines south of the south side frontage road on Main Avenue. Trenching will begin on the shoulder of the road with the line eventually moving where the frontage road currently runs.
Excel’s digging will begin just east of 45th Street and move west toward I-29 and is expected to last at least a month. Xcel Energy also began work on the east side of I-29 where the frontage road turns south along I- 29.
From 2005 to 2007 I-29 from Main Avenue to County Road 20 will be reconstructed and widened, to include three lanes northbound and southbound from Main Avenue to 19th Avenue North.
“There is not enough room for all the traffic,” Gorder said. “The pavement was 30-plus-years old and had reached the end of its design life. We looked at the 20-year traffic projections and built to those expectations. Twenty-year traffic projections indicate that traffic on Interstate 29 between Interstate 94 and 13th Avenue could reach 70,500 vehicles a day, compared with abut 48,000 vehicles a day in 1998.
At the intersection of I-29 and 13th Avenue, traffic for 2020 is projected to reach about 50,300 vehicles a day, compared with about 38,100 in 1998. And at the intersection of I-94 and I-29, which was just completed, traffic is expected to reach 53,000 vehicles by 2020, compared with about 21,000 in 1998.
Overall on the entire project to date, 11 bridges have been completed and two more are scheduled for 2004, Gorder explained. Work on a total of 15 bridges is included in the entire project, which is to continue through 2007.
New Techniques
With the I-29 project, Gorder said they have started incorporating some high-density concrete decks. In 2002 DOT used three different concrete mixes, including a control structure that was straight cement, another bridge has a mixture that has 38 percent of the cement replaced with flyash, which adds density and controls heat a little so it could control cracking, thus eliminating the incorporation of corrosives, Gorder said.
A third deck contained ground granulated blast furnace deck cement, which included slag cement, again working toward increased density, Gorder explained. Sensors were included in the bridges, providing feedback on whether corrosives are entering the bridge decks.
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