Rapid growth on the east side of Memphis has caused significant traffic congestion and safety issues at the I-40/I-240 Interchange in Shelby County, TN. With continued growth, the interchange is projected to be overwhelmed with more than 350,000 vehicles daily by 2035. BH had designed the initial (Phase I) interchange improvements, which were completed in 2003, and TDOT contracted with BH to design the Phase II improvements.
Phase I replaced portions of the original interchange and provided the new interchange with an increased capacity for the traffic going around the south side of Memphis via I-240. It also shifted roadways and ramps to provide room for Phase II improvements.
Later Phase II infrastructure improvements improved the flow of traffic through this highly traveled area. The project included the roadway and structures from Sam Cooper Boulevard to the White Station overpass, I-40 from Sycamore View to Covington Pike, and I-240 to the north side of the Walnut Grove interchange. The existing low-speed ramps carrying the eastbound and westbound I-40 movements were replaced by higher-speed, fly-over structures with two lanes each. Within the limits of the project, I-40, I-240, and Sam Cooper Boulevard were widened with an additional lane in each direction. Also, the ramps and intersection at the Covington Pike Interchange were redesigned. This added additional lanes and reduced queues which had been backing up into the I-40 through lanes. The Phase II design and subsequent construction improved traffic capacity and efficiency. The final configuration includes four levels rising to approximately 75 feet, the first of its kind in West Tennessee.
Buchart Horn designed the project under an accelerated schedule to help the Tennessee Department of Transportation procure federal funding that became available very late in the design phase. Three months were shaved from the design schedule and TDOT successfully secured the federal funding commitment.
Buchart Horn provided the following design services during Phase II of the project:
Traffic Analysis
As a part of the project, traffic and ramp studies were performed to include improvements at the I-240/Covington Pike Interchange. These studies examined the need for auxiliary lanes to allow for the proper merge of westbound traffic leaving the I-40/I-240 Interchange. The studies also looked at providing additional lanes and dual left-turn lanes to eliminate congestion at the Covington Pike Interchange and eliminate traffic queues onto I-40.
Field Surveys
Additional field surveys were necessary to provide information along the new extended project segments. To expedite the project’s completion, Buchart Horn personnel performed the surveys as the design was being developed.
Roadway Design
The design of additional lanes, turn lanes, and ramps from the I-40/I-240 Interchange north on I-240 and at Covington Pike was required as a part of the improvements.
Right-of-Way Design
Right-of-way plans were developed for the initial project limits and the new work areas. This included the establishment of right-of-way, drainage easements, and construction easements.
Signing and Pavement Marking Plans
Due to the intricacies of the project, extensive signing and pavement marking plans were required. Existing signage structures were evaluated for use in the future, and new structures and signing added to guide drivers through the interchange. Pavement marking plans were developed to further aid in safe and efficient travel for the public.
Traffic Signal Plans
The improvements made at the I-40/Covington Pike Interchange required an update of the existing signals. The intersection was fully signalized with technology that included video detection and LED signal heads.
Maintenance of Traffic
Because of the critical nature of the traffic flow through this interchange to the citizens of Memphis, it was important to provide the public a safe and efficient work zone to navigate the project. Buchart Horn developed extensive maintenance of traffic plans to accomplish that. Various strategies were used, resulting in minimized impacts to the traveling public.
Erosion Prevention and Sediment Control
Prevention and control of sediment on the project required careful design. Buchart Horn professionals certified in erosion and sediment control provided the proper design to protect the adjacent areas from sediment runoff.
Construction Quantities
Experienced personnel from Buchart Horn and its subconsultant used advanced quantity calculation tools available in GeoPak along with manual methods to provide an accurate estimate of the construction quantities.
Buchart Horn provided the following services during construction:
Construction Engineering and Inspection (CEI) and Engineering Support Services
After design completion for Phase II, TDOT selected the Smith Seckman Reid, Inc. team, supported by Buchart Horn and other local firms. Buchart Horn supported the CEI team by providing bridge/structural inspection on the overall project and responding to Requests for Information from the contractor.
Public Involvement
Buchart Horn’s design team members assisted Smith Seckman Reid in presenting the project and its construction impacts to several professional, governmental, public, and educational groups. At these meetings, Buchart Horn and CEI personnel gave presentations, fielded questions, and prepared displays. The displays included animations, renderings, project boards, and handouts.
Transportation
