A Hitachi excavator is used to move rocks on the site.
The Virginia Department of Transportation (VDOT) is nearing the end of a design-build project to replace the Washington Boulevard bridge over Columbia Pike in Arlington, Va. The $48.5 million contract was awarded to Shirley Contracting Company LLC. Work began in the spring of 2012, and is expected to be complete this summer.
According to VDOT, “the new bridge will be wider, longer and a great deal more attractive than today’s structure.”
A light well will separate westbound and eastbound lanes, and an acceleration/deceleration lane will be added westbound between ramps to assist weaving. The new bridge will accommodate turn lanes, a raised median, a wider sidewalk and a 10-ft. (3 m) shared-use path on Columbia Pike. Clearance under the bridge will be increased to 16 ft. 8 in. (5 m) to accommodate a future area streetcar. Several ramps also will be reconfigured to improve access, traffic flow and increase capacity.
In addition, the existing box culvert that conveys Long Branch through the center of the interchange will be replaced with a double-cell box culvert and extended to reduce erosion at the downstream end.
“Overall, the project is most challenging because of the limited work/project area,” said Christiana Briganti-Dunn, VDOT project manager. “We are working on four interchanges between two major roadways, all within a half mile footprint. Because of the limited project area, work must be done through multiple traffic switches. Prior to these traffic switches, the traveling public, as well as the surrounding neighborhoods, are notified via email chain, PCMS boards which are posted on relevant roadways a week in advance, and updates from Shirley (SCC) are provided for VDOT’s Web site.”
Briganti-Dunn noted that another major challenge of the project comes from the mass amount of utilities that run along Columbia Pike.
“Many of SCC’s storm runs were installed next to and parallel to groups of utilities,” she explained. “That means hand-digging for hundreds of feet of pipe to be installed. With so many existing utilities, it also makes it challenging to incorporate new utilities under the roadway. SCC is continuously having utilities marked by MISS Utility and test pitting prior to any excavation to ensure that our workers are safe and that no utilities are damaged.”
Structural aspects of the project also posed some challenges of their own.
“SCC had to set up a weekend detour, starting on a Friday night at 9 p.m. and finishing the following Monday morning at 4:30 a.m., that closed the area of Columbia Pike running under the Washington Boulevard bridge,” Briganti-Dunn said. “Traffic was detoured up to and across Washington Boulevard to access the other side of Columbia Pike. This weekend detour was needed four times in order to demolish half of the existing bridge, erect five girders for the new northbound bridge, demolish the remaining portion of the existing bridge, and finally erect the four girders for the southbound bridge. These closures involved detour sign set-up, hundreds of delineating barrels, arrowboards, and PCMS boards, as well as many manpower hours to ensure the detour was safe for the travelling public as well as SCC workers and easy to follow.”
According to Briganti-Dunn, the other challenging structural aspect of the job involves the 460 LF (140 m), cast in place, double 10 x 8 box culvert that runs under two bridge abutments, under Columbia Pike, and under an access ramp from Columbia Pike to southbound Washington Boulevard.
“The culvert is being built in four piece-meal phases, and SCC is currently working on the last section, which is the outfall,” she explained. “Strategic planning, detailed surveying and a strong team effort have carried SCC through the multiple phases of culvert installation.”
Major pieces of equipment used throughout the project include an 80-ton (72.5 t) crawler crane, a 50-ton (45 t) rubber tire crane, a track excavator, an attenuator truck, arrow boards and PCMS boards.
A community working group of citizens, Arlington County and VDOT staff developed concepts for the bridge’s architectural and aesthetic treatments, including decorative pylons in each corner, steel fascia girders with a two-tone paint scheme to mimic the existing arch, a relief pattern incorporated into the vertical outer surfaces of the bridge parapet to create shadows and visual interest, a concrete block pattern on retaining and abutment walls similar to Pentagon architecture, recessed, arched panels on the abutment walls, medallions with images reflecting the historical significance of the Freedmen’s Village, for which the bridge will be named, and color and anti-graffiti application to concrete surfaces.
VDOT noted that the existing single-span bridge was built in the 1940s by the War Department as part of the Pentagon Roadway Network. It is a thick, solid structure with deteriorating concrete, corrosion and heavy chloride contamination. It also has withstood many years of increasing traffic loads.
The bridge was rated as “poor” in structural inspections, meaning that the superficial concrete was in poor condition, but is still sufficiently capable of carrying traffic without risk to the public.
Washington Boulevard carries more than 80,000 vehicles each day over Columbia Pike. VDOT noted that the design provides enhanced safety, mobility, and aesthetics for pedestrians, bicyclists and motorists.