After something of a false start, a major project along a busy stretch of Interstate 55 in the Jackson metropolitan area is now moving smoothly towards completion. The Mississippi Department of Transportation (MDOT) is expanding an eight-mile section of I-55 South, from south of the city of Byram to McDowell Road in Hinds County.  The expansion project, which will add one lane in each direction, is designed to provide much needed relief to a very heavily travelled corridor, reducing travel times and increasing traffic efficiency. The project is scheduled to be complete in the late summer of 2018.

Mississippi Transportation Commissioner Dick Hall comments, “Using a travel demand model for this area to estimate vehicle hours per day with and without this project, and an average wage rate for Hinds County from the Bureau of Labor Statistics, this project has the potential to save drivers approximately $5 million per year in wages the first year open to traffic, and up to $6 million per year by 2040.”

AFTER ORIGINAL CONSTRUCTION START, DESIGN FLAWS STOPPED THE PROJECT

The project began in 2014, when MDOT awarded a contract for reconstruction of the interstate segment.  However, work on the project was abruptly stopped in early 2015.  As MDOT Executive Director Melinda McGrath recounts, “In January 2015, MDOT and the active contractor mutually agreed to terminate the contract during the middle of the construction phase. At that point, all traffic was in a head-to-head configuration in the southbound lanes. Three interchange ramps were also temporarily closed which presented a major challenge to local traffic. These were designed only as temporary traffic configurations and were not intended to be in place for an extended period. 

“MDOT stopped work on the project due to a design flaw in the retaining walls along the interstate as well as unanticipated soil conditions. We then let the project as a design-build contract; however, the lowest bid in this process had several major errors and could not be awarded. Other bids exceeded the state’s estimate and were not viable options.”

A field survey was made to determine which items of work contained in the initial project had not been constructed.  The plans were quickly prepared for all remaining items of work needed to complete an interim phase, diverting traffic out of the head-to-head configuration. Engineering firm Neel-Schaffer of Jackson was selected by MDOT to prepare plans for an interim project that would complete the active phase of construction; this project was let to contract and successfully completed within the required schedule, and it included the expedited reopening of the three closed interchange ramps.

McGrath continues, “MDOT then determined the plan requirements for the final construction project.  Some of the major changes in project approach included modifications to the hydraulic structures.  These changes were needed for each of the intermediate phases to be constructed and for all structures to hydraulically function as required as stand-alone segments.

“Major changes were required in order for proper drainage to occur throughout the construction phase.  Once again, an extensive amount of coordination was required during plan development.  The plans were completed within the required five-month period which allowed MDOT to move quickly into the advertisement phase for the final construction project. This also allowed MDOT to move from the completion of the interim project into the construction of the final project without delay.”

A total of 11 retaining walls were required to improve constructability of the project.  Soldier pile walls were used at locations where widening of the roadway cut into the existing frontage road side slopes.  These walls utilized closely spaced steel or concrete piles with a cast-in-place concrete stem.  The piles reinforced the side slopes to prevent slides while weak roadway base soils were removed.  One cast-in-place concrete T-wall on a pile-supported footing was used to prevent roadway fill from spilling over onto the frontage road.  A soil nail wall was used to shorten the front slope of an existing bridge to accommodate widening of the roadway.

During the redesign process, Neel-Schaffer also handled lighting, traffic signals, and intelligent transportation system (ITS) elements. The ITS plans were redesigned to update them to new equipment and remove two of the four dynamic message system (DMS) signs that had already been installed under a separate contract. Although no traffic signal work had begun, Neel-Schaffer did a complete redesign of the signals, including new detection and phasing to utilize the latest Flashing Yellow Arrow signal heads.

AS CONSTRUCTION RESUMED, PROJECT WAS SPLIT INTO TWO PHASES

Construction on the project resumed in July 2015; to address public concerns and complete the project in a timely manner, MDOT made the decision to divide the remaining work into two phases. The priority for Phase One was to open all exit ramps as soon as possible and improve travel safety by moving traffic to the outside, away from the existing head-to-head configuration. The new $21.3 million contract for Phase One construction was approved by MDOT and awarded to James Construction Group of Baton Rouge, LA in June 2015. Penalties were established, to be charged if a substantial completion date in December 2016 was not met. Final completion date was to be in April 2016.

During the time allotted for Phase One construction, Phase Two plans were reviewed for accuracy and prepared for the final project. The start of Phase Two construction was scheduled to begin immediately following the completion of Phase One. 

“MDOT made the right decision to begin a new contract that has proven to be the best value for the taxpayers of Mississippi,” McGrath comments.  “The top priority items for Phase One were completed in an efficient and timely manner.”

Construction of Phase Two began on April 15, 2016. The $85 million contract for this phase was awarded to Yates Construction of Philadelphia, MS. “Included in this contract are the reconstruction of the southbound lanes of Interstate 55 from McDowell Road to Byram,” McGrath reports. “The median is also being reconstructed, and new roadway lighting is being added to the medians. Retaining walls between the southbound lanes of Interstate 55 and the frontage road are also being built as part of this contract. Additionally, MDOT will install a new traffic signal at the Byram interchange and Intelligent Transportation System (ITS) components such as traffic cameras and dynamic message signs.”

In January 2017, crews shifted traffic to a head-to-head configuration from McDowell Road to Savannah Street to work on expanding the southbound lanes. Traffic will remain in this configuration for the remainder of construction. Due to crashes along the project, lane closures had to be scheduled for work on repairing barrier walls and guardrails that were damaged by motorists.

While the I-55 South Expansion project has seen its share of delays, restarts, and traffic flow issues, the result is likely to be worth all the frustration. As Commissioner Hall states, “Once completed, this section of Interstate 55 will have six lanes to provide a smoother and more efficient route to commuters and travelers, and will benefit an area that has seen a great deal of economic growth and development in recent years.”