11th Street Bridge Replacement

Major bridge and interchange reconstruction in Washington, DC utilizing lightweight aggregate fill to reduce settlement and protect historic infrastructure.

The 11th Street Bridge Replacement Project rebuilt a critical transportation corridor connecting Capitol Hill, the Anacostia Freeway (I-295), and neighborhoods east of the Anacostia River. The project replaced aging bridges and constructed new highway and local roadway connections to improve traffic flow, safety, and regional mobility.

The reconstruction included multiple new bridges and interchange improvements carrying tens of thousands of vehicles daily across the Anacostia River. As part of the project, engineers had to accommodate sensitive subsurface conditions and protect historic stormwater outfall structures dating back to the 1850s located beneath portions of the project area.

Stalite Lightweight Aggregate was used as lightweight fill in areas where new embankments were constructed above these historic structures. By significantly reducing the weight of the fill material, the lightweight aggregate minimized settlement and reduced loads on the underlying infrastructure. In some areas, up to 20 feet of new fill was required, making lightweight aggregate an effective solution for maintaining stability while accelerating construction of the bridge approaches and roadway embankments.