Innovative Approach to Reconstruct Part of Mississippi’s Interstate 55 Garners Two Statewide Awards

April 28, 2016

Company’s Design of  Split-Diamond Interchange Creates Efficiency, Capacity for Future Growth

The American Council of Engineering Companies of Mississippi (ACEC/MS) recently presented Michael Baker International with two statewide awards for designing the reconstruction of three miles of Interstate 55 in Madison County, one of the largest construction projects in the state. Michael Baker’s creation of a split-diamond interchange to enhance capacity, access and efficiency for a growing part of the region won both the Grand Conceptor and People’s Choice awards at the annual ACEC/MS Engineering Excellence Awards, held in March.  

I-55.jpg"The Mississippi Department of Transportation (MDOT) presented us with quite a challenge when we were selected to redesign this critical section of I-55, an area known for persistent gridlock that is also near several businesses, including a car dealership and printing shop," said Ray Balentine, PE, PLS, office executive for Michael Baker’s Mississippi operations. "Our local focus and constant collaboration enabled us to generate solutions that balanced the needs of commuters with the concerns of local businesses, and we’re proud of this recognition from ACEC/MS."

MDOT charged Michael Baker with preliminary and final design for the section of the interstate from Old Agency Road to State Route 463. Michael Baker’s split-diamond interchange concept included frontage roads, several bridges and retaining walls.

Among Michael Baker’s innovations for the project was the design and development of Colony Park Boulevard, a new east-west route for the city of Ridgeland that provides access to the interstate in a growing area. Rather than construct the new roadway over the interstate and hinder future growth, Michael Baker designed the road to pass under I-55. To accomplish this, Michael Baker experts created a complex system to alternate head-to-head traffic on the northbound and southbound lanes of the interstate. Crews then constructed the bridges on top of the existing ground using drilled shafts and temporary casings prior to pouring the caps, placing the beams and pouring the deck. Once the new bridges were in place, workers excavated the ground below the interstate for the development of the new roadway. 

To minimize the impact to local businesses, Michael Baker created tangential shaft retaining walls near the newly constructed access roads that became part of the split-diamond interchange. This avoided the extensive excavation necessary to construct conventional retaining walls, which would have been more expensive and disruptive to the operations of the nearby companies.

“Madison County routinely ranks in the top three counties in Mississippi for population growth and economic development,” said Melinda McGrath, P.E, executive director for MDOT. “The split-diamond interchange on I-55 represents a well-designed roadway that handles increased traffic on this route. Michael Baker’s design will continue to function well into the future, serving as an asset to state and local governments as they continue to recruit and attract high-end developments.” 

Completed in July of 2015, the three-year project had a total cost of more than $90 million.

Above photo:
Pictured left to right: MDOT Executive Director Melinda McGrath; MDOT State Bridge Engineer Justin Walker; Northern Transportation Commissioner Mike Tagert; MDOT Assistant Chief Engineer Amy Mood; Southern Transportation Commissioner Tom King; Kenny Collins, Project Manager, Michael Baker International; Central Transportation Commissioner Dick Hall, Ray Balentine, Vice President, Alabama & Mississippi, Michael Baker International; MDOT Roadway Design Engineer Richard Pittman. (photo credit: Equipment World)