The Naval Operational Support Center is a new 37,500 SF building. It features LEED design specifications, Low-Impact Development (LID) principles, stormwater management, and Anti-Terrorism/Force Protection.
Major geotechnical considerations affecting the project were 1) presence of up to 10 feet of uncontrolled existing fills at the site; 2) presence of moderately expansive near surface soil; 3) excessive static and seismically-induced settlement; 4) high frost potential; 5) strong ground shaking; 6) presence of layers with high seismic compaction potential; and 7) earthquake-induced landslide.
AGS developed the Basis of Design (BOD) and Schematic Design Documents and the firm provided architectural, civil, and geotechnical services for the project.
The purpose of the geotechnical study was to characterize subsurface conditions and develop site-specific geotechnical and seismic design criteria for the proposed structures in accordance with UFC 1-300-09N and UFC 3-220-01.
Field Exploration: After reviewing existing geotechnical data, aerial photos, and site history, the team conducted a field exploration program consisting of a total of drilling seven (7) borings, four (4) seismic cone penetration tests (SCPTu), and one infiltration test. Prior to performing the field exploration program, permits were obtained from the governing agencies and utility clearances were performed. During the field investigation, a Photoionized Detector (PID) was used to provide a qualitative assessment of potential soil contaminants. All field activities were coordinated with the air-force base staff and project manager.
Laboratory Testing: AGS performed a laboratory testing program on selected samples of earth materials obtained during the field exploration program.
Development of site-specific seismic design parameters: AGS developed site-specific seismic design parameters in accordance with Section 3.5 of FEMA 450 document. AGS followed procedures outlined in FEMA 450 and FC 1-300-09N to develop seismic design parameters. The measured shear wave velocities from SCPTu were used in our seismic analysis.
Analyses and Report: AGS’ geotechnical findings, conclusions and recommendations along with the supporting field and laboratory data were presented in a geotechnical report. After reviewing the proposed grading plan, it was recommended that the most cost-effective mitigation measure against undocumented fill and high seismic compaction potential was to remove and replace the existing fill. Slope stability analyses under static and seismic conditions were performed and soil reinforcement was recommended for the embankment.
Civil Engineering: AGS’ Civil Engineering team provided detailed grading and drainage design for the new building and parking lot, as well as utility supply to the building, and stormwater management improvements around the building and within the parking lot.
