DESCRIPTION

The Millennium project is an expansion of Arlington National Cemetery adjacent to Fort Myer. The project will ultimately provide additional interment spaces; two committal shelters; Fort Myer perimeter wall/gate and jogging path; stream restoration; roadway and maintenance drive; pedestrian sidewalks/stairs and bridge; site furniture including benches; and utility relocation and extension. The project will also include several retaining walls along the perimeter and interior of the site leading up to two bridge structures which will span a stream and environmentally‐sensitive areas.

CHALLENGE

The bridges on the project were originally designated as design‐build components to be provided by the General Contractor. The retaining walls leading up to the bridges were design‐bid‐build items which were designed by the owner to be cast‐in‐place (CIP) concrete walls supported on auger cast piles. The walls have a natural stone facing. The challenge was developing an economical bridge design that was less expensive than CIP walls on auger cast piles and would meet the performance criteria of the adjacent
CIP walls on auger cast piles. An additional consideration was providing future access for the sanitary sewer line and a 36‐inch casing for a ductile iron water line that would be installed below the roadway and on top of the bridge through the MSE wall backfill.

20 Foot Rise and 42 Foot Span

Geopier Layout under Arch Footings and MSE Wall Abutments

Needed to Consider Influence of Embankment Fills on Arch Footings – Used 3D Settle to Determine Stresses

SOLUTION

GeoStructures provided design/build services for the two bridges. EcoSpan Concrete Arches were used to span the streams and environmentally‐sensitive areas and EarthTec MSE walls were utilized for retaining the embankment fill. The MSE wall facing panels contained dovetail slots which were used to attach the stone facing to the panels. In lieu of auger cast piles, Geopier Rammed Aggregate Pier® elements were utilized to control settlement of the concrete arch footings and adjacent retaining walls. Bridge #1 was approximately 30 feet tall with back‐to‐back walls to retain the roadway fill and utilities. A special interior wall was provided to create a utility corridor to access the sewer and water lines.

Construction Arch Footing

Precasting the Arch Segments

MSE Wall with dovetail slot facing panels being installed next to Arch

Stone Masons Facing the Walls