The area has been growing for some time, driven in part by the proximity to the headquarters of Walmart and Tyson Chicken – both located to the south in Arkansas. Traffic studies forecast that traffic will continue to grow from its current volume of 21,035 vehicles per day to 29,469 vehicles per day in 2041. Trucks make up 25 percent of the traffic volume.
Currently, I-49 ends in Pineville, Missouri, so commuters traveling between the two states typically use the existing U.S. 71 which connects to I-49. U.S. 71 runs through Bella Vista, Arkansas, where it has several signalized intersections. This causes routine delays and traffic backups.
“Currently, commuters that were on the interstate have to travel through a signalized town, which leads to frequent back-ups,” says Marvin Morris, MoDOT’s Resident Engineer on the project. Morris is responsible for administering the contract and providing high level oversite.
The team will also be building two conventional bridges. One will be along the I-49 northbound lanes and travel over U.S. 71 southbound lanes. The second will be on Missouri Route 90 and over I-49.
A diamond interchange is being installed at Route 90, which will cross the extension of I-49. This corridor has a high volume of traffic and the interchange will help to keep it flowing.
MoDOT and the prime contractor for the project, Emery Sapp & Sons Inc., installed three large triple box culverts to enable the water to cross the road.
“We have to accommodate the water that naturally flows down into the valleys,” Morris says. “We can’t hinder the flow otherwise it will back up on the landowners.” Elk River, the closest body of water to the project, is partially filled by the runoff in the area. “The highway is acting like a damn, so we needed to put something there to drain the water.”
It’s expected that there will be approximately 4.9 million cubic yards of earth removed for the project. Rather than removing the dirt from the work area, the designers aimed for a balanced site, meaning the rock that will be used to fill in the valleys will be used to smooth out the roadway. This acts as a cost savings since hauling the earthworks away is pricey.
“During the initial excavation, we found the quality of rock was not consistent with the boring logs,” Morris says. To minimize the impact to the project, MoDOT established teams consisting of engineers, construction inspectors, and geologists to work with the contractor to identify areas that may be impacted.
The contractor performed exploratory borings throughout the project. “With this information, we were able to use the rock quality as determined by our geologists to design a new set of cross-sections that allowed us to maximize any vertical benches where we had good rock quality,” says Morris.
To support the new fill, the team is installing 11 special structural design pipes and box culverts. “Under the high fill sections, we are putting in reinforced steel to handle the dead load of the dirt, and the live load of the automobiles,” Morris says. “This is being specially designed to handle the load.”
They are currently under budget on items paid to date. Morris explains how this came about. “By teaming with the contractor, we’ve realized additional savings through the value engineering process.” The contractor was able to re-design MSE walls, the Route 90 bridge over I-49, median drains, and leave in place forms for structural boxes and median pavement. “By redesigning these items, we’ve ended up with a better, safer product that will have a lower impact and cost less to maintain.”
The value engineering process has enabled the team to realize an additional total savings in excess of $503,000.
However, there’s no reason to celebrate yet as differing field conditions concerning the quality of the rock encountered on this project could impact final totals.
Morris says good communication and teamwork between MoDOT and the contractor has allowed the project to proceed on schedule and meet the lofty goals originally set.
“We have weekly team meetings where we track critical items as the project progresses and continually communicate so everyone is on the same page and aware in advance of any challenges that may arise,” Morris says. In addition, there has been the formation of special teams between MoDOT and contractor to ensure prompt responses to challenges as they arise.
Finally, Morris credits the contractor. “You need a major contractor to put together a team to make this happen. Emery Sapp is conscientious and takes pride in their work.”
When the I-49 Missouri/Arkansas Connector Project is complete, the traveling public will have an interstate-standard highway that adequately and safely serves their needs and promotes economic development and freight movement. The new footprint will also remove the daily backlog, allowing commuters a more reliable road.