Last October, citizens in Iowa celebrated a historic milestone in transportation infrastructure improvements: the completed expansion of U.S. Highway 20 to a high-speed, four-lane expressway that connects the state’s eastern and western borders. The timeline of this project is what’s most astounding – it took six decades to complete.
Transforming the corridor from two to four lanes began in the 1950s with two individual sections being completed on opposite sides of the state – one east of Moville, the other near Dubuque. The first 3-mile section of expressway was completed in northwest Iowa in 1958; the remaining 299 miles were completed in bits and pieces throughout the years as funding allowed.
The final four-lane section of U.S. 20 in western Iowa covers 40 miles, extending from east of Moville in Woodbury County to just west of Early in Sac County. Constructed between 2014 and 2018, the final section was completed last October. The corridor now extends 302 miles to connect Sioux City with Fort Dodge, Waterloo, and Dubuque.
“Like many transportation infrastructure projects, the completion of a four-lane U.S. 20 across Iowa has taken a persistence of vision,” says Mark Lowe, Director of the Iowa Department of Transportation (Iowa DOT). “It took the passion, hard work and dedication of countless individuals over decades to bring that vision to life.”
Governor Kim Reynolds adds, “With the completion of the U.S. 20 build-out, we have effectively connected the Missouri to the Mississippi through some of the most productive agricultural lands in the northern half of our state. This is a significant milestone, considering Iowa is the second-largest exporter of agricultural goods in the country, and reliable, efficient transportation from border-to-border is critical to our ongoing success."
The 40-Mile-Long Home Stretch
In 2014, work began to modernize the final 40 miles of U.S. 20 in Iowa. The bulk of construction activities occurred between 2016 and 2018, and the cost to complete this segment totaled $286 million – including costs for right-of-way acquisitions, design, soil investigation, utility relocations, and other incidentals not contained within the original construction bid of $228 million. This last portion of the project was made possible in part due to a 10-cent-per-gallon fuel tax increase approved by the Iowa legislature in 2015. At the time Iowa DOT was facing an annual $215 million shortfall in its road construction and repair budget; the tax hike provided the state with desperately-needed funds to move forward with hundreds of road and bridge projects.
The final 40 miles of expansion was divided into six sections. The first section began construction in June 2014 and applied to about 8 miles of roadway, starting 2 miles east of Moville to west of Correctionville. Workers began by grading and paving the westbound lanes between Moville and Minnesota Avenue, then switched to grading and paving the eastbound and westbound lanes from Minnesota Avenue to Correctionville. Next, crews continued grading and paving operations on roughly 3.5 miles of the eastbound lanes between Moville and Minnesota Avenue. For work on the westbound lanes, an $11.9 million grading contract was awarded to C.J. Moyna & Sons, a firm located in Elkader, Iowa. Paving of the westbound lanes, between Moville and Minnesota Avenue, was handled by Dubuque, Iowa-based Flynn Co. under an $8.9 million contract. C.J. Moyna oversaw both grading and paving activities on the eastbound lanes under a $19.8 million contract.
Dual bridges were also constructed over Wolf Creek and the Little Sioux River. C.J. Moyna's contracts included construction of a continuous concrete slab (CCS) bridge over Wolf Creek. Peterson Contractors, a national firm headquartered in Reinbeck, Iowa, was selected as the prime contractor to build two pretensioned, prestressed concrete beam (PPCB) bridges over Little Sioux River for $29 million.
Dixon Construction Co. of Correctionville, Iowa, handled on-site construction of all bridge structures for Section 1. According to Iowa DOT’s Office of Bridges and Structures, the state generally uses CCS bridges for short spans up to 59 feet and lengths up to 150 feet on stream and small valley crossings. Meanwhile PPCB bridges are used for longer spans up to 155 feet.
The next two sections consisted of grading and paving approximately 1 mile of the eastbound and westbound lanes of U.S. 20 within the city limits of Correctionville, as well as 0.7 miles of the northbound and southbound lanes of Iowa Highway 31 from southwest of Correctionville to just north of U.S. 20. Knife River Corp., one of nation’s largest construction materials and contracting firms, was given the $6.8 million contract for Sections 3 and 4. The work was completed during the 2015 construction season.
Section 4 was comprised of grading and paving operations on approximately 11 miles of U.S. 20 eastbound and westbound lanes (from east of Correctionville to the west junction of U.S. 59 in Holstein). Ames Construction, which is headquartered in Minnesota with regional offices throughout the U.S., won the $62.8 million contract for this section.
Work continued in Section 5 under a $36 million contract given to C.J. Moyna. Workers tackled just over 7 miles of grading and paving along the eastbound and westbound highway lanes, from the east junction of U.S. 59 in Holstein to west of Adams Avenue near Galva. The prime contractor also oversaw the erection of two rolled-steel beam bridges over Maple River and two PPCB concrete beam bridges over Fritz Creek.
C.J. Moyna spearheaded the final section of construction under a $45.8 million contract, which involved grading and paving a 9.5-mile stretch of roadway between west of Adams Avenue in Galva to west of U.S. 71 near Early. Crews built dual PPCB bridges over Boyer River, and wrapped up project activities with paving and overlay of detour areas.
Innovative Solutions Fast-Track Progress
It took over half a century to convert Iowa’s U.S. 20 corridor into a continuous high-speed expressway; however, reconstructing the last 40 miles occurred in the blink of an eye. A project of this scale and magnitude usually runs the risk of having multiple interruptions to the construction schedule. Right-of-way acquisitions alone could have been a scheduling nightmare, considering 224 parcels were on the docket. Extensive coordination with 19 utilities companies was also required to identify and resolve utility conflicts prior to the lettings.
Despite all the moving pieces and potential roadblocks, project officials praise the fact that they were able to complete the project under an aggressive timeline without any significant issues or delays.
To speed progress, project designers specified wick drains at each of the mainline segments. “The installation of prefabricated, synthetic vertical drains helps to accelerate the consolidation of deep, soft, saturated and compressible soils, such as areas adjacent to waterways and low-lying areas found within the project zone,” notes Steve McElmeel, PE, Construction Engineer, District 3, Iowa DOT. This innovative geotechnical solution fast-tracked settlements in deep fills and, for certain soil types, even hastened settlement times.
Workers installed nearly 1 million linear feet of wick drains on the U.S. 20 project. “Wick drains were typically installed in both a triangular and a square grid pattern with each wick drain spaced anywhere from 4 to 12 feet apart,” McElmeel continues. “A specialty piece of equipment was used to place the wick drains up to a depth of over 40 feet by the wick drain subcontractor. A ‘granular blanket’ consisting of a sand layer and/or transverse collectors of the same wicking material were then placed to drain the water away. As fill material was placed over these areas, excess water was ‘wicked’ up the drains and then away from under the roadway, which allowed the targeted soil types to compress and settle at an accelerated rate.”
The team’s use of precast concrete structures on Section 4 was also key to completing the project on an accelerated schedule. Instead of using a cast-in-place construction method for large box culverts, crews installed precast boxes, round pipe and precast arches for culverts. While Iowa DOT originally specified portions of the final alignment as cast-in-place only, precast alternates were allowed for most of the drainage structures. Once Iowa DOT’s chief engineer determined that precast box culverts would be conducive to an accelerated construction schedule, members of Ames Construction, C.J. Moyna, and Hancock Concrete (a Minnesota-based provider of concrete, drainage and pipe solutions) worked with state officials to create a sound construction strategy.
“The pre-cast option was not previously considered due to the depth of fills, plus significant design assurances were needed from the contractor to allow use,” adds McElmeel. “Before and during fill placement, the project team analyzed box culvert settlements to glean helpful data for future projects.”
A Corridor for Commerce
U.S. 20 is a coast-to-coast route spanning between the Pacific Northwest and New England, and serves as one of the main arterials used to transport Iowa commodities to various cities and seaports across the country. As such, many of the state’s citizens and business owners feel the widened highway improves economic development opportunities by easing the movement of people and goods.
“Iowa’s population is shifting more toward urban areas. However, manufacturing still thrives in this part of the world, as does production agriculture,” said Ann Trimble-Ray in an October 2018 interview with the Demoines Register. Trimble-Ray, who is Vice President of Early, Iowa-based Heartland Marketing Group, is also connected with the Highway 20 Corridor Association, a coalition of many groups and citizens supporting the U.S. 20 expansion.
Designed to enhance safety and mobility as well as bolster commerce, the improved U.S. 20 corridor provides an alternative to the frequently-congested Interstate Highway 80 traversing Iowa’s midsection. “There is no limit to the possibilities for economic impact this four-lane highway will have in northwest Iowa,” adds Shirley Phillips, President of the U.S. 20 Corridor Association. “It will attract new opportunities for communities across the region.”
Highlights of U.S. 20 Project
Noteworthy Project Stats
U.S. 20 Project Bolsters Iowa’s Dominance as Top Exporter
Containing roughly 30.5 million acres of farmland, Iowa is one of the country’s top producers of corn, eggs, pork and soybeans. The state is also home to more than 6,000 manufacturing firms, crafting everything from heavy-duty construction equipment and aerospace components to micro-plastics used in medical devices. Iowa currently ranks seventh among all states in its percentage of gross domestic product (GDP) from manufacturing. In terms of exports, Iowa was considered the 27th largest state exporter of goods in 2017 with $13.4 billion in exports, reports the Office of the U.S. Trade Representative. In 2016, state exports supported an estimated 94,000 jobs.
For members of the trucking industry, taking U.S. 20 could potentially cut miles from freight routes. “The opening of U.S. 20 will be of great benefit to the trucking industry of Iowa, since it opens another route for trucks to take across the state,” said the Iowa Motor Truck Association in an October 2018 news release. This alternate corridor could provide many end users with lower freight costs and speedier delivery, which in turn would stimulate further economic activity – a real perk for Iowa’s economy.
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