Jensen Construction of Sioux City, Iowa, was awarded a $56 million contract to build a new bridge over the Missouri River immediately north of the existing bridge.
It’s been years in the works — and even more years will pass before work is completed — but two of the Council Bluffs Interstate Systems improvements projects are currently under way. Plans aim to update and widen Interstates 80, 29 and 480 within the Council Bluffs metropolitan area in an effort to improve mobility through the region by upgrading the I-80 and I-29 corridors, improving the condition of the roadways, reducing traffic congestion and crashes, and adding capacity.
“Most of the traffic is through traffic, a high percentage of which is truck count,” states John Carns, Council Bluffs Interstate Systems project coordinator assigned to the project five years ago. “We want to separate it [from local traffic] so it can get through town fast, reduce chances of a conflict.”
Average daily traffic numbers range from 20,000 to 75,000 vehicles, with trucks accounting for 11 to 25 percent of those vehicles. According to the Iowa Department of Transportation, some areas of I-80 are experiencing more than twice the number of vehicles than the traffic volume estimate used during the original design anticipated. By 2030 traffic on I-80 between the I-29 interchanges is expected to increase to more than 120,000 vehicles a day and double the current 20,000 vehicles per day volume on I-29 north and south of I-80.
Some of the increase can be attributed to population growth, but Carns believes a lot is due to the number of residents who live in Council Bluffs but work in Omaha, Neb. Housing is affordable on the Iowa side of the Missouri River, he explained, but Nebraska offers more job opportunities, due in part to new bio diesel, power and ethanol plants and a Google server farm.
The Council Bluffs interstate system was constructed in the 1960s and developed to the design standards of the time. Except for routine maintenance projects in the 1980s and 1990s, significant changes have not been made to the roadway.
Time Will Tell
The city of Council Bluffs and Metropolitan Area Planning Agency conducted a System Needs Study of the interstate system in Council Bluffs in 1997 that revealed features that don’t meet current design standards, guidelines or operational criteria and do not provide adequate traffic capacity. Five years later, Iowa DOT initiated the Council Bluffs Interstate System improvements project to address the issues raised by the study and to develop solutions for improving the interstate system in the Council Bluffs metro area.
In 2006 the Iowa DOT constructed a short-term solution to congestion problems in the form of an interim project on the overlapping section of I-80/I-29. By adding a third lane in the eastbound direction, it was able to ease some of the congestion that occurs where eastbound I-80 and southbound I-29 merge.
The long-term plan developed by the Iowa DOT, in cooperation with the Nebraska Department of Roads and the Federal Highway Administration, includes reconstruction of 18 mi. (29 km) of mainline interstate (I-80, I-29 and I-480) and 14 interchanges (three interstate-to-interstate interchanges and 11 interstate-to-local street interchanges), a new bridge over the Missouri River, reconstruction of the 24th Street Bridge over Interstates 29 and 80, construction of a dual divided freeway and additional lanes. As Carns put it, work will span “two states, two major cities, two counties and one river crossing.”
Due to the magnitude of the improvements and limited availability of funding, the interstate improvements are scheduled to be constructed in multiple stages, each of which will take years to complete. Carns explained that funding comes from the normal state budgets, at a pace of $75 million a year. At this funding level, it will take until 2022 to build, he said.
“We didn’t ask for federal stimulus money; that’s going to other projects that wouldn’t get funded otherwise.”
But before the multi-year project could get started, several years of environmental studies and design had to be completed.
“Because of the size of the project,” Carns said, “We needed a record of decision.”
The tiered environmental process uncovered “no major environmental issues,” he noted, although they did decide to alter the design in order to move the new bridge to the north side of the existing bridge to lessen the impact on the zoo, parks system, etc.
Tier 1 focused on the entire interstate system to identify the needs of the system and develop alternative solutions. An Environmental Impact Statement was prepared to document the system study. Due to the magnitude of the improvements, at the end of Tier 1 the interstate system was divided into segments for further study. Tier 2 focused on detailed engineering and environmental studies for each segment of the interstate system.
An “environmental holdup” developed, Carns said.
“The Corp of Engineers changed the requirements for raising and lowering levees.”
The CBIS is one of the first projects to encounter this change, which required risk assessment and reliability studies and a peer review by an external consultant, as well as a lengthy (3 to 6 months) federal review process for approval. The result entailed the relocation of one levee.
Consolidation of the railroads into one corridor held up the project two years, Carns said.
“There are four railroads; they came to us with a proposal.”
At a cost of $30 million, they lowered the profile of the interchange, closed 6 to 8 crossings and shortened the bridges over fewer railroads. The consolidation idea has yet to be presented to the public, he added.
Another far-reaching preliminary step was “major” right-of-way acquisition.
“We have all [of the necessary ROW] on our side of the river for segment 1,” Carns said, but there are still three parcels to get in segment 2 —mostly condemnation, he said, adding that there is “contention over one plot.”
He said they still need to buy ground in segment 3, the industrial part of town with railroads, a grain elevator, etc.
In addition to the newly purchased ROW, the Iowa DOT has been buying and tearing down houses to make way for additional lanes.
“We’re working on about 10 to 12 hardship home acquisitions,” Carns elaborated, “even though we won’t be working there until 2025 to 2030.”
He explains that the houses are being torn down immediately due to liability and safety concerns.
Bridge to the Future
The first contract was let two years ago, Carns said. Reconstruction of the 24th Street Bridge over Interstates 29 and 80 — what he called “the gateway into the city” — was the first project and involved reconstructing the bridge to make it longer in preparation for full reconstruction of the I-29/I-80 overlap section in segment 2. Carns said the 2,400 ft. (732 m) bridge project involved “lot of ramp work.”
The longer bridge will allow future I-29/I-80 lanes to pass underneath. In addition, 24th Street from just south of 27th Avenue to the I-29/I-80 eastbound ramp intersection was reconstructed and now includes two through lanes in each direction and accommodation for left-turn lanes at the interstate on-ramps.
Jensen Construction of Sioux City, Iowa, was awarded a $56 million contract to build a new bridge over the Missouri River immediately north of the existing bridge. Henningsen, out of Council Bluffs, Iowa, did the grading and paving on the approach to the bridge. A second bridge is needed to be able to provide five lanes in each direction on I-80. The new bridge is expected to be completed in 2010.
The existing bridge will be widened to five lanes in October under a separate contract, with both bridges and approach roadways expected to be completed in 2011. Carns said crews will widen and replace the deck on the old bridge, with painting and paving being done, and alternating lanes for the work to accommodate the traffic switchover. Lane shifting will be done in traffic zones for safety purposes.
“By October, we’ll move traffic, tear the deck off and replace it.” Cairns said. “We’ll build 3 to 5 lanes in the clear, then close lanes and build 3 to 5 more lanes in the clear and move traffic. We’ll ’stair-step’ the work.”
Despite the organizing, Carns said getting trucks in and out is a challenge.
Because of the extent of the project and the time-released funding, the project will be implemented in smaller, manageable segments. Boundaries were established in Tier 1 to divide the system into five stand-alone segments with logical ending points that could be designed and built independent of adjacent segments, according to Tier 2 environmental documents.
Segment 1 begins in Omaha, Neb., just east of the I-80/I-480 system interchange and continues across the Missouri River to just west of the I-80/I-29 west system interchange in Council Bluffs, Iowa. This segment includes improvements to the 13th Street interchange (in Nebraska) and construction of a second bridge over the Missouri River north of the existing bridge.
Segment 2 begins on I-80 just west of the I-80/I-29 west system interchange in Council Bluffs and continues to just east of Indian Creek. The segment also includes I-29 through the west system interchange, north to and including the Union Pacific Railroad bridge. Work includes reconstruction of the west system, 24th Street and Nebraska Avenue interchanges.
“I-80 [from the west system interchange to Indian Creek] will be a dual divided freeway,” Carns noted. “The interior six lanes will be express lanes with no local exit access. The outside six lanes will have access to the service interchange.”
Construction on Segment 2 is expected to begin in 2012.
Segment 3 begins on I-80 just east of Indian Creek and continues to a point northeast of the Madison Avenue interchange. This segment includes construction of the dual divided freeway from Indian Creek to the east system interchange. The segment also includes I-29 from south of the U.S. 275/Iowa 92 interchange, north to and including the east system interchange. Engineers on the project team are working to develop design plans for Segment 3. Construction on Segment 3 is expected to begin in 2012.
Segment 4 begins on I-29 north of the Union Pacific Railroad bridge and continues to a point just west of 25th Street. Currently, this segment includes the I-29/I-480/West Broadway system interchange and interchanges at 41st Street, Avenue G, Ninth Avenue and 35th Street. Two concepts are under consideration for Segment 4 improvements, both of which provide direct access to West Broadway from I-29 via one-way frontage roads as was decided in the Tier 1 Final Environmental Impact Statement.
Segment 5 begins on I-80 northeast of the Madison Avenue interchange and continues 1.3 mi. to east of the U.S. 6/Kanesville Boulevard interchange. Key features of the segment 5 improvements include adding three lanes in each direction on I-80 and reconstruction of U.S. 6/Kanesville Boulevard interchange to a partial cloverleaf with loop ramps.
Engineers will do corridor modeling for Segment 3 and beyond, Carns indicated.
But First …
“There are a number of firsts on this project,” Carns said. They needed to develop a financial plan. Total costs will be tracked through the project and reported to the Federal Highway Department. Because of the extended time frame of the work, there is concern about going drastically over budget.
“The ’Big Dig’ in Boston started with a $2 billion budget,” he explained, “but ended at $22 billion. We can’t do that here. If we go over 2 percent, we have to explain why.” But, he addeds, 2 percent won’t even cover the cost of inflation.
“We scoped the project in 2005 at $500 million, but it could easily push to $1.1 billion with contingencies.”
One way to try to keep the budget in line is by allowing the contractor the choice of recycling the old material that is removed.
“The quality of the aggregate is not good and it’s overlaid with asphalt, so we can’t reuse it,” Carns explained.
New material will be determined six months before letting, but Carns said it will probably be all Portland Cement Concrete.
“The department has a bias for concrete, but we try to keep a balance between the two industries [concrete and asphalt] and you need good aggregate.” CEG
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