The project involved constructing a vehicle barrier wall at the Thomas Jefferson Memorial to create a pedestrian plaza, add additional parking, increase security, and permanently close the existing U-shaped driveway. The barrier wall was expected to be approximately 2,400 feet in length, 3 feet in height, and designed to resist the impact of a 15,000 pound vehicle traveling at 50 mph.
GeoConcepts coordinated directly with the National Park Service and the US Park Police to conduct a geotechnical field investigation at the memorial to evaluate the subsurface conditions. This included submitting a detailed work plan and information for background checks of all on-site personnel.
GeoConcepts recommended three foundation options for the wall including spread footings on in-situ soils, spread footings on impact piers, and spread footings on controlled modulus columns. Recommendations were also presented for lateral earth pressures, backfill, and drainage for use in retaining walls. GeoConcepts recommended soil stabilization techniques to significantly reduce costs of installing foundations.