5. 11th Street Bridges
PROJECT COST: $260 million
Key Facts: Location: Washington, D.C.
Owner: District Dept. of Transportation, Washington, D.C.
Design-Builder: Skanska USA Civil, Alexandria, Va.; Facchina Construction, La Plata, Md.
Engineer: JMT, Sparks, Md.
Start Date: December 2009
Completion Date: Summer 2013
In a city filled with monuments and memorials to national milestones, the 11th Street Bridges project is making some history for the District Dept. of Transportation. Along with being the agency�s largest-ever construction project, it�s also the first to use a design-build-to-budget procurement process.
Two continuous steel, multi-girder bridges will be constructed between the existing 930-ft-long, 63-ft-wide bridges to provide better connections between the Anacostia Freeway (DC Route 295) and the Southeast-Southwest Freeway, as well as an alternate evacuation route.
A third new bridge will be dedicated to local traffic and feature a shared bicycle and pedestrian path, and streetcar rails to allow for future connectivity. Improvements to two interchanges will also provide local traffic with better access to DC 295, and boosting economic development along both sides of the Anacostia River.
More than 100 meetings were held with federal agencies, neighborhood groups, civic associations and other organizations to gain community input on the bridges� appearance and construction impacts.
Construction began with pile driving for the 12 river foundation piers. More than 61 hollow, concrete-cylinder piles with an average length of 110 ft were driven 70 ft into the riverbed. This step was followed by pile driving on both sides of the river for the connecting ramps and related freeway improvements.
The bridges will have a design life of 75 years.