Froehling & Robertson, Inc. was integrally involved in all three phases of the development of the National Museum of African American History and Culture, an historic, $500 million museum celebrating African-American history and culture. F&R was retained to perform a full geotechnical literature review, a complete geotechnical study, and a complete Phase I and Phase II environmental assessment with full geotechnical and environmental reports.
F&R’s engineering services were completed on the most prominent site on the National Mall in Washington, DC. While designs were being conceptualized, F&R’s geotechnical engineers were tasked with overcoming significant challenges regarding site development including high groundwater levels. The building was designed to extend 47 feet below the groundwater table. Analysis showed that dewatering would result in a conical depression extending below the Washington Monument, inducing further settlement of the structure. F&R’s geotechnical professionals addressed these and other concerns as follows:
- Developing a Support of Excavation System that acted as a permanent hydrualic cut off during excavation and will continue to operate after construction, thereby isolating the site from adjacent historic structures.
- Designing a hybrid system of mat foundation and driven piles to support column loads of 700,000 kips.
- Performing geostructural monitoring during pile driving to ensure significant vibrations were not produced causing detrimental effects on adjacent structures.
- Performance of a feasibility study to assist architects and engineers in the development of a geothermal system to support LEED® certifcation. Due to the limited area undergound and the deep foundation system, a 600 foot 150 well Kelix geothermal system was proposed.
F&R also provided supplementary geotechnical support during the final stages of construction.