The original 1.7-mile two-lane bridge spanning the Potomac River from Newburg, MD, to Dahlgren, VA, had a long history of significant traffic delays with backups extending up to five miles from the bridge. There were numerous collisions annually due to the narrow two-lane configuration and absence of a median barrier. For wide loads, the bridge would need to be closed from both approaches to allow access and safe passage of large cargo.
For this replacement project, the Skanska-Corman-McLean (SCM) Joint Venture along with bridge design engineer AECOM proposed an innovative bridge design that incorporated efficient and cost-effective span lengths, structural performance, constructability and maintainability considerations that saved the Maryland Transport Authority (MDTA) over $37 million in project costs while improving aesthetics and lowering long-term maintenance costs.
The $462.9 million Gov. Harry W. Nice/Sen. Thomas “Mac” Middleton Bridge Replacement project included the design and construction of a new 61-foot-wide bridge, with four 12-foot-wide lanes and a center median to increase traffic capacity, improve safety and visibility and facilitate access for wide-load vehicles. The new bridge was designed and constructed to cost-effectively balance the number of spans against the number of the supporting piers.
Bridge Project Incorporates Many “Firsts” for MDTA
The project incorporated many firsts for MDTA, including selecting design-build as the project delivery method: 210’ – 66” cylinder piles with carbon-fiber pre-stressing strands; design and installation of 200-ton pre-cast bathtubs; pre-casting 80-ton concrete drainage troughs; incorporating ChromX reinforcing steel in the bridge deck; and integrating modular joints to the deck.
In addition, several unique sustainable practices were performed in this project:
- Reuse of 18,000 cubic yards of Potomac River sediment delivered to the Weanack Reclamation site which uses river mud to reclaim and transform over 100 acres of highly productive agricultural fields and wildlife habitat.
- Approximately 9,500 tons of materials from the original decommissioned bridge will be used to enhance the habitat, including transporting the old concrete to an artificial reef site.
- MDTA worked with partner agencies to plant nearly 12 million live oysters on the 148-acre natural Lower Cedar Point Bar.
|Client/Owner:||Maryland Transportation Authority MDTA|
|Design-Build Firm:||Skanska USA Civil Southeast Inc.|
|General Contractor:||Skanska USA Civil Southeast Inc.|
|Specialty Contractors:||Century Engineering/Systra IBT Joint Venture (Independent Design Quality Management)|
|Owner Advisor:||JMT/WSP Joint Venture Team|
|Project Cost:||$462.9 Million|
|Construction Duration:||32 Months|