GeoConcepts provided geotechnical services during both design and construction phases for three mixed-use buildings as part of the Reston Heights development: a 17-story building with two basements, a 13-story building with two basements, and a 12-story building with four basements. Development challenges included foundations and excavation support due to the moderately sloping site and areas of deep existing fill.
GeoConcepts completed over 10 geotechnical engineering reports at the site. These reports were based on a total of approximately 50 soil test borings, and in-situ pressuremeter testing to obtain more accurate soil modulus values. Based on their engineering analyses of the data collected GeoConcepts provided foundation and ground improvement recommendations customized to each portion of the site. Ground improvement measures included the use of rammed aggregate piers to increase soil support capabilities so that spread footings could be used instead of more costly deep foundations. Since the project was considered a “critical structure” project by Fairfax County due to the size of the buildings and the complexity of the foundation systems, all geotechnical engineering reports were reviewed and approved by the Fairfax County Special Projects Division.
During the various construction phases of this project GeoConcepts provided full-time observations and testing services for foundation installations, poured in place concrete, structural steel, and earthwork operations. Due to its “critical structure” status these services were provided in accordance with the Fairfax County Special Inspections Program.