The New Frederick Douglass Memorial Bridge

2024 Bridge of the Year

The New Frederick Douglass Memorial Bridge is a replacement in designation only.

Yes, it technically took the place of an old structure bearing the same name crossing the Anacostia River in Washington, D.C. But it’s much more than a link between two sides. The owner and design team envisioned a structure that would fit with Washington’s timeless architecture--a bridge that is classic but not classical, dramatic but not theatrical.

The result is the one-of-a-kind, above-deck arch design that opened in September 2021, replacing a bridge built in 1950. The new Frederick Douglass Memorial Bridge (FDMB) is 1,444 ft long with two 452-ft side spans and a 540-ft center span, significantly exceeding the minimum horizontal navigation channel width to open the waterway for all users.

Structural steel was the only solution for the bridge to achieve its signature arches, which have a variable hexagonal shape and a variable depth from the base to the crown. The three sets of lighted, parallel arches spring high above the water and nearby landmarks, visually marking the sky across the river between the increasingly dense western Buzzard Point neighborhood of Washington and the park-like neighborhoods of Poplar Point and Anacostia to the East.

The bridge provides a positive bank-to-bank connection, with the arch profile suggesting the path of a stone skipping across the water. Unlike other D.C. arch bridges, the desire was to extend the arches vertically above the deck to create a landmark structure.

The illuminated arches can produce any number of color schemes to celebrate occasions and holidays in D.C., including pink for the District’s cherry blossom festival, rainbow colors for Pride month, and red, white, and blue for Independence and Veterans Day. In a city of arch bridges and national monuments, the FDMB stands out with its majestic above-deck arch design.

The bridge’s namesake, Frederick Douglass, is celebrated throughout the structure. The bridge connects the D.C. neighborhoods where he worked and lived and is visible from the Frederick Douglass Historical Site in Anacostia. At each overlook, commemorative plaques share Douglass’s legacy as an abolitionist, orator, writer, and statesman. Images of the FDMB are also featured on new D.C. driver’s licenses.

The ovals at the approach of each entrance provide a unique application for traffic calming, smoothly moving 70,000 vehicles over the bridge per day. They also provide an urban oasis from city congestion by offering generous outdoor spaces with landscaped, park-like settings. The 2.7-acre ovals are each almost two football fields long and one football field wide. The ovals also offer the opportunity for future monuments on either side of the bridge.

Achieving the Arches

Once the concept was envisioned, the design team only considered steel for the arches due to their complex geometry. The team worked together on many of the fabrication design and detailing issues that arose throughout the design phase.

The arches’ cross sections are hexagonally shaped to enhance the arches’ visual appearance, which casts shadows that decrease their visual mass. Apart from each arch being symmetric about its centerline, the rib section constantly varies throughout the side and center arches from base to crown.

The arch is a constant 9½ ft wide at the web break, but the location of the web break travels up the section as the arch rises. The top web is angled at 15°, and the bottom web is angled at 30°, forming a kite shape from which the arch hexagon is extracted. The side arches vary in depth from 14½ ft at the abutment to 6 ft at the crown and back to 13½ ft at the V-pier. The center arches vary in depth from 13¾ ft at the V-piers to 7 ft at the crown.

The arches employ an unbraced design to provide an unobstructed view above the deck. The central arch is 20 ft higher than the side arches and has a 168 ft elevation above the water, a tremendous visual impact for travelers entering and exiting the nation’s capital. The three-arch system was designed to allow the superstructure to move freely through the arches with expansion joints only at the ends of the structure. The arches are supported by concrete V-piers with the same cross-section as the steel arches, allowing for a seamless visual transition.

Steel gave the arches a seamless look from the outside, with all detailing occurring inside the arch section. The arches utilize butted splices that are entirely internal, providing improved aesthetics without external bolted splices. The arch base connection is also entirely internal, providing a seamless transition to the V-pier and protection for a critical connection. The six arches support 88 stay-cables with hangers in a vertical plane outside the deck edge, reducing the potential for falling ice on the roadway below. The steel floor system provides a robust and economical system that carries three lanes of traffic in each direction, along with generous 18-ft-wide shared-use paths on each side of the bridge. All the sections are I-shaped plate girders with a composite precast panel deck. The edge girders are at a constant depth, with most of their length composed of Grade 50W steel. The sections at the V-piers are composed of Grade HPS 70W steel where the edge girders are not cable supported, but instead span between supports on the V-pier legs. Also at the V-piers, overlooks cantilever out past the arches to provide unobstructed views of the Anacostia River and the city, including the adjacent Navy Yard and Nationals Park.

One of the most challenging design aspects was the arch sections’ butted splices. The arch splices that connect the segments had to be fabricated with high precision and tight tolerances to ensure an easy bolted fit-up in the field. Any misalignment of the arch segments could have resulted in the whole arch becoming out of tolerance. The arch splice ring plates were 3D scanned and match milled so an exact fit could be achieved. The result was a tight connection with a clean visual that uses fewer bolts than a typical splice connection.

The hexagonal cross-section of the arches seamlessly transitions into the V-pier substructure to obtain the skipped-stone path of the structure. Unlike most steel-to-concrete connections, which typically have a base plate external to the section, all parts of the anchorage are internal to the arch section. That layout created several challenges that needed to be considered and overcome, including arch bearing stiffener/anchor rod layout, edge spalling effects of the concrete V-pier, baseplate details and fabrication, and coordination with V-pier post-tensioning detailing.

The design and analysis of such a unique arch shape brought about many challenges in detailing and fabrication. The design team utilized global and localized 3D models to analyze the behavior of the arches. Because of the unique shape, the steel arch rib required stiffening in various locations on the top flange, bottom flange, top web, and bottom web, which were not consistent throughout the arch.

The decision to use internal splices came early in the project. A ring plate is at the start and end of each arch segment and at each anchorage. Managing all the stiffeners ring plates and constantly changing geometry required close coordination with the detailers so the section could be fabricated efficiently. Even though the arch is primarily a compression member, its shape and unbraced nature mean tension stresses occur in the section. The team worked to eliminate any poor fatigue details within the section, often requiring complete joint penetration welds or stiffeners that terminated with a ground radial transition.

Several iterations of stiffener and anchor bolt layouts were evaluated for use at the arch base. The team used hand calculations for the initial design. For the final design, it developed a local finite element model composed of shell elements for the steel plates, tension-only members for the anchor rods, and springs to model the combined stiffness of the underlying concrete and grout. The arch base connection utilizes large 2½-in. diameter anchor rods to transfer the large bi-axial forces that arise with the unbraced arch design.

The team worked closely with the fabricator and installers to ensure that all tightening equipment would fit between the stiffeners for the large anchor bolts. An anchor plate that matches the geometry of the base plate is embedded deep into the concrete V-Pier to transfer any tension forces that arise in the anchor bolts. The original FDMB had a swing bridge span adjacent to the new bridge and a central pier that was in the middle of the navigation span, which resulted in the need for a temporary navigation channel to be offset to one side of the center arch during construction. The temporary channel prevented any temporary support from being placed in that location.

The two side arches were initially erected using two temporary supports per arch. Since only one support could be placed for the center arch, the east side of the center arch was erected using temporary cables attached to the side arch until the keystone arch piece could be placed. Because the temporary navigation channel was offset, the floor system construction proceeded asymmetrically over the bridge length, which required arches to support the asymmetric dead loading.

Several efforts economized the steel fabrication and minimized the long-term maintenance. The bridge has four-way symmetry, giving it economy of repetition even with the arches’ complex detailing. The floor system and railings were detailed with as much repetition as possible. Where additional strength was needed for the edge girders over the V-piers, grades of steel were varied instead of varying the cross section, keeping detailing consistent throughout the structure.

The 18-ft shared-use path on each side allows for under-bridge inspection vehicles or aerial lifts to be driven to the edge of the structure for easier inspection. The arches are placed outside of the roadway width, allowing for minimal roadway closures and easier inspection. The bridge was also designed for a 100-year service life using several high-performance materials and coatings, reducing long-term maintenance needs.

Community Staple

The bridge creates extraordinary value for Washington in many ways other than cost. Community members, commuters, and visitors enjoy the bridge’s signature profile and vastly improved transit and mobility opportunities. They also directly benefit from a wide array of project-related public investment programs designed to better the region on both sides of the river.

The FDMB’s sustainable urban design, bridge innovation, and dramatic presence have spurred equitable societal and economic growth within southeast Washington along both riverbanks. It augmented multimodal connections for pedestrian, bicycle, and transit and created a waterfront esplanade for Buzzard Point, a once bare and neglected community.

On the other bank, Poplar Point’s visionary plan integrates FDMB’s urban design features and helped facilitate a new, mixeduse neighborhood surrounded by generous parks and natural open spaces. The areas feature enhanced recreational and cultural amenities and extend the Anacostia community to the river, enlivening the water’s edge.

The project’s large-scale public programs expanded participants’ vision of societal connection and helped attendees obtain education to better their job possibilities. The most notable is the District DOT’s local hiring initiative, a first-of-its-kind federally funded on-the-job training program to hire and train women and minority candidates named “Strive – Build the Bridge to Your Future.” The program mentored next-generation civil engineers, and a construction on-the-job mentoring program delivered design, construction, and construction management training.

“The new Frederick Douglass Memorial Bridge is a fitting tribute to an iconic Washingtonian and a forefather of Black excellence who we continue to emulate and who helped build Washington, D.C., into the city we are today,” Washington Mayor Muriel Bowser said during the bridge’s ribbon cutting ceremony. “This project was never just about getting people from Point A to Point B; it was about building a more connected D.C. by connecting Ward 8 and Ward 6, connecting residents to jobs and prosperity, and connecting our entire community to the future of multimodal transportation.”

Project Team

• Owner: District of Columbia Department of Transportation, Washington, D.C.

• General contractor/erector: South Capitol Bridgebuilders (SCB), joint venture of Archer Western and Granite Construction, Washington, D.C.

• Structural engineer: AECOM, Glen Allen, Va.

• Lead bridge architect: BEAM Architects, Bridgport, U.K.

• Erection and construction engineer: McNary, Bergeron & Johannesen, Hartford, Conn.

• General engineering consultant: HNTB, Arlington, Va.

• Steel team:

  • Fabricator: Veritas Steel LLC, Eau Claire, Wis. and Palatka, Fla. *AISC full member; AISC-Certified fabricator*

  • Detailer: Tensor Engineering, Indian Harbour Beach, Fla. *AISC associate member*