U.S. 71 is a limited access four-lane highway that moves north to south through the state of Missouri. Approximately 30 mi. (50 km) south of Kansas City, the highway is receiving a long awaited upgrade.
In February 2002, the Missouri Department of Transportation (MoDOT) awarded a $16.7 million contract to Ideker Inc. of St. Joseph, MO, to remove the existing pavement, upgrade the bridges and install new reinforced concrete pavement. The project length is 3.59 mi. (5.7 km).
According to Brian Dewey, MoDOT field engineer, the project was constructed in two stages. The first stage took place in the 2002 construction season when the southbound lanes were reconstructed.
“The only milestone date stipulated in the contract required the new southbound pavement to be opened to traffic by November 1, 2002,” he said.
The project involved a research component, as well.
“This job was one of three pilot MoDOT projects that incorporated QC/QA testing on portland cement concrete pavements. [PCCP],” Dewey said.
“In the Quality Control /Quality Assurance environment, the contractor employs certified technicians to perform and document quality control checks of methods, materials and pavement dimension tolerances. MoDOT inspectors perform enough random quality assurance tests to verify that the QC results remain valid and accurate.
“In this process, Ideker was allowed a little more freedom to design concrete mixes allowing the use of more cost effective materials,” Dewey continued. “They partnered with aggregate producers to hold tighter tolerances on quality and gradation that might affect pay factor statistics. Other immediate benefits were that Ideker could dictate its own schedule for material testing and thus reduce the amount of labor that had to be employed by MoDOT to ensure quality control.”
According to Dewey, “Long term benefits are yet to be seen or realized. This was a pilot project. The jury is still out and it will take some time to determine if this type of contracting will be a sign of the future, or a flash in the pan.”
All design engineering was performed in-house by MoDOT, Dewey said.
Two bridges that crossed an abandoned railroad right-of-way were replaced with reinforced concrete box culverts to accommodate a proposed bike path. Four steel girder bridges — two on the northbound lanes and two on the southbound lanes — had their substructure widened by adding an additional girder line. These four structures then had new slabs placed on steel decks.
Two voided slab bridges that crossed Missouri Route 2 were widened to accommodate a wider auxiliary lane and shoulder for the interchange. New concrete wearing surfaces were constructed over the new and existing decks. Comanche Construction of Olathe, KS was the bridge subcontractor.
The old pavement was concrete and dated to the early 1960s. Asphalt overlays were added in later years as the original concrete deteriorated.
This asphalt was cold-milled by subcontractor Columbia Curb & Gutter of Columbia, MO, said Mark Sloop, project engineer for Ideker. Ideker’s fleet of Cat excavators and Volvo articulated trucks removed the old concrete. Where possible, the old concrete was incorporated with rock and earth for project fill requirements.
The new pavement has an anticipated life expectancy of 35 years which is 15 years longer than the 20-year design life of the pavement being replaced.
The contract provided no financial incentive for early completion, however a $4,900 per day liquidated damage for late completion was included.
Dewey described the pavement’s specs: “The paving area is 22 inches in thickness. The base is 4 inches thick and is composed of Type 5 aggregate. Next is the bituminous permeable base, which is 4 inches thick. The concrete pave is 14 inches thick and composed of non-reinforced PCCP, with 15-inch joint spacing.”
The 2003 construction season saw some the hottest days in recent memory, which prevented Ideker from pouring concrete during daylight hours. Additionally, U.S. 71 has high numbers of commuter traffic and leisure traffic traveling to the large Missouri lakes to the southeast.
According to Sloop, Ideker chose to place the concrete during the evening to avoid both the heat and the high traffic volumes.
Concrete equipment used by Ideker included a RexCon Model S mixing plant, with a 12-cu.-yd. (9.2 cu. m.) drum. This plant was set up just off one of the exits along the project. Concrete placement equipment included a CMI 450 spreader, 6004 placer and a Rex Belt placer.
The MoDOT contract provides a financial incentive for smoothness. A 100-percent incentive could be achieved if smoothness was in the 12.1-to-15-in. (30.2 to 37.5 cm) variation per mile. Bonuses, up to 10 percent, could be awarded for lower numbers and deductions down to no pay applied to higher indexes.
According to Sloop, Ideker achieved 100 percent compliance by diamond grinding pavement variances. Highway Services of Minneapolis, MN, provided these services.