Multiple contractors are working on expanding U.S. 20 in Iowa to four lanes for the Iowa Department of Transportation.

"The stretch we are working on is the final 40 miles to complete U.S. 20 in Iowa to four lanes," says Shane Tymkowicz, District 3, Assistant District Engineer for the Iowa Department of Transportation.

The project through rural communities stretches from east of Moville to Early. The 31 miles from Correctionville to Early were not in the department's original five-year construction program. It was accelerated, after the state passed a gas tax, in 2015, which allowed more funds to become available for DOT projects.

"One of the projects that benefited from that was the U.S. 20 project," Tymkowicz recalls. "The projects were added to the program so the work could be completed by 2018."

Work began in 2014 and is scheduled to finish in 2018. Iowa DOT divided the project into six sections.

"Each of these were substantial projects in length and dollar amount," Tymkowicz says.  

Each package included bridges, box culverts, grading and concrete paving: 10-inch thick on the roads and 6-inch thick on the shoulders. Iowa DOT typically breaks projects into smaller units of work, for instance, grading in one direction and then paving in that direction, often in separate years, due to the winter.

"So the work could be coordinated, we put it under one prime contractor," Tymkowicz says.

Prior to the bid packages of section 4, 5 and 6, the Iowa DOT held pre-bid meetings to go over the staging, required work and work schedules.

"This was to assist contractors with understanding the schedule and work scope requirements," Tymkowicz says. "The goal was to let the projects as quickly as possible to give contractors adequate time to complete construction by the fall of 2018."

The department also gave the contractors the option of cast-in-place or precast on most of the box culvers.

Section 1

Running from east of Moville to Correctionville, Section 1 was broken into two parts: the west and the east portions.

West Portion

C.J. Moyna & Sons of Elkader, Iowa, received the $11.9 million grading contract for the westbound lanes. In addition to 2.4 million cubic yards of grading, the work included construction of eight box culverts and a 150-foot by 40-foot slab bridge over Wolf Creek.

Flynn Co. of Dubuque, Iowa, received the $8.9 million paving project. The major bid items were the mainline pavement, paved shoulders and side road connections. This work included 153,000 square yards of granular sub-base, 128,000 square yards of concrete pavement and 34,600 square yards of concrete paved shoulders. 

Eastbound, the department awarded C.J. Moyna the $19.8 million contract in October 2016 to construct eight box culverts, the EB slab bridge over Wolf Creek, grading and paving the eastbound lanes.  The project is targeted for completion in the fall of 2018. The work includes 780,000 cubic yards of grading, 151,000 square yards of granular sub-base, 126,000 square yards of concrete pavement and 35,000 square yards of concrete paved shoulders.

East Portion

Peterson Contractors of Reinbeck, Iowa, received the $29 million contract for the east portion in October of 2015, with completion expected in October 2017. Scope includes grading and paving of the eastbound and westbound lanes, pipe jacking, culvert construction and building two bridges, each 386 feet long and 40 feet wide over the Little Sioux River. The bridges used pretensioned prestressed concrete beams. The quantities involved were 2.3 million cubic yards of excavation, 118,000 square yards of concrete paving, 28,000 square yards concrete paved shoulders, and 149,000 square yards of granular sub-base. Crews jacked 640 feet of steel pipe under the existing roadbed, to avoid the need to place deep cuts through the existing road.

"This project had additional challenges in that it included cuts as deep as 65 feet and fills in excess of 50 feet," Tymkowicz says. "In order to assist in controlling settlement, nearly 300,000 lineal feet of wick drains were installed on the project."

Iowa DOT allowed for a detour during the first year of construction to assist with staging for the eastern portion. The department let a separate contract to widen the detour route and remove trees, while design was still taking place.

"The detour allowed for a larger change in grade elevation of new roadway than could have been done under traffic," Tymkowicz says. "It also allowed for the contractor to have access to both the eastbound and westbound lanes at the same time."

Section 2 and 3

Knife River Corp. in Sioux City, Iowa, completed the second and third sections at Correctionville in 2015, under a $6.8 million contract. The work included 42,700 square yards of concrete pavement.

Section 4 

Continuing from east of Correctionville to Holstein, the 11.2-mile Section 4 began in December 2015, with a target finish in 2018. In 10 months the DOT purchased right of way, relocated utilities and let the project to Ames Engineering for $62.8 million. The work includes 12 box culverts, 4.6 million cubic yards of excavation, 458,000 square yards of granular sub-base, 628,000 cubic yards of topsoil, 204,000 linear feet of wick drains, 392,000 square yards of concrete and 95,000 square yards of concrete paved shoulder. In addition, more than 1,200 feet of trenchless reinforced concrete pipe, ranging from 24 to 54 inches was used to accelerate construction, maintain drainage and reduce differential settlement, Tymkowicz explains. 

"By having a single prime contractor to manage the schedule, the construction period was reduced to less than three years," Tymkowicz says.

Section 5

This fifth 6.7-mile section runs from Holstein to near Galva, and C.J. Moyna received the $36 million contract in February 2016. It is projected to finish by fall 2018.  

The work includes grading and paving the east and westbound lanes and four bridges. The two bridges over Fritz Creek are 253-feet by 40-foot and use pretensioned prestressed concrete beams. The two bridges over the Maple River are 340-feet by 40-feet and use rolled steel beams. The project has a twin and triple box culvert that needed to be stage constructed to maintain traffic. In addition the project included 1,240,000 cubic yards of excavation, 260,000 square yards of granular sub-base, 250,000 cubic yards of topsoil, 180,000 linear feet of wick drains, 221,000 square yards of concrete pavement, and 53,800 square yards of concrete shoulders. The contract also included more than 1,700 feet of trenchless reinforced concrete pipe, ranging from 14 inches to 66 inches in diameter.

"They have to maintain two lanes of traffic at all times," Tymkowicz says. "What would normally take us four to five years, they have three years to do."

Section 6

The final section continues from Galva to near Early. CJ Moyna received the $45.8 contract for this section in September 2016 and must complete it by October 2018. The scope includes grading and paving, and building two 304-foot by 41-foot bridges, using pretensioned, prestressed concrete beams over the Boyer River; and four box culverts. The project includes 620,000 cubic yard of excavation and select treatment, 560,000 cubic yards of topsoil, 445,000 square yards of granular sub-base, 99,000 linear feet of wick drains, 374,000 square yards of concrete pavement and 92,600 square yards of concrete shoulders.

This section will have a detour for the duration of construction. Tymkowicz says, "by removing traffic, it should help speed the construction activity."