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San Bernardino County, California
Geotechnical Engineering in San Bernardino County, CA
Subsurface investigations, laboratory soils testing, and geotechnical reporting to characterize site conditions before design and verify them during construction. San Bernardino County is covered on a project basis through our Los Angeles, CA regional hub.
- Lead time
- Scheduled by phone or proposal; lead time confirmed when the scope is set
- Laboratory
- Sugar Land, TX laboratory under chain of custody, or a mobile laboratory for large projects
- Reporting
- Reviewed and issued under a documented quality system; formatted for owner, engineer, and building-official review
- Serving
- San Bernardino County, CA — Los Angeles, San Diego, San Jose
- Coverage
- California statewide · 27 regional hubs
- Technicians
- ACI- and NICET-certified field staff; licensed professionals in California
- Call us
- (346) 420-5425
Scope
Geotechnical services in San Bernardino County
- Soil borings and sampling programs sized to the structure and site
- Laboratory index testing: Atterberg limits (ASTM D4318), moisture content (ASTM D2216)
- Moisture-density relationships and bearing evaluation for foundations and pavements
- Expansive-soil characterization for slab and pavement design
- Construction-phase verification: proof rolls, subgrade acceptance, fill placement observation
ASTM D4318ASTM D2216ASTM D698ASTM D1557
Full scope, standards list, and pricing basis: Geotechnical Engineering.
Local conditions
Geotechnical conditions in San Bernardino County
San Bernardino County spans desert basins, mountain ranges, and active fault systems that create some of the most geologically varied building conditions in California. Expansive clays in the valley floors can damage slabs and foundations when moisture content shifts seasonally. Alluvial fan deposits common across the Inland Empire transition rapidly from dense gravels to loose silty sands over short distances, and proximity to several active fault traces means seismic site classification is a core design requirement under CBC and IBC Chapter 20. Before a structural engineer can size a footing or a civil engineer can grade a pad, the subsurface needs to be understood, not assumed. Our geotechnical services for San Bernardino County projects include subsurface drilling and sampling programs, laboratory soils testing, and engineering reports that deliver bearing capacity values, expansion index results, liquefaction screening, and grading recommendations in the format California-licensed engineers and county plan checkers expect.
Valley soils in much of San Bernardino County frequently exhibit moderate to high expansion potential, making ASTM D4829 expansion index testing a practical necessity rather than an optional add-on for residential and light commercial foundation design. Concrete placement schedules may also need to account for the region's wide diurnal temperature swings and prolonged dry periods, which affect curing and require attention during hot-weather concreting per ACI 305R guidelines.
FAQ · San Bernardino County
San Bernardino County sits near several active fault zones. What seismic deliverables should my geotechnical report address for CBC compliance?
For CBC and IBC Chapter 20 compliance, your report should establish the site seismic design category by characterizing the upper 30 meters of soil—Vs30—to assign a Site Class per ASCE 7. Where liquefiable saturated sands or loose alluvial fill are present, a liquefaction hazard evaluation is expected. Fault setback compliance under the Alquist-Priolo Earthquake Fault Zone Act may also apply depending on project location and occupancy.
My project is on an alluvial fan in the Inland Empire portion of the county. Should I expect variable soil conditions across the pad?
Yes. Alluvial fan deposits characteristically change from dense gravels near the fan apex to looser, finer-grained sediments toward the toe, sometimes within a single building footprint. Boring spacing and depths should be designed to detect these transitions rather than assume uniform conditions. ASTM D1586 Standard Penetration Test sampling at regular depth intervals helps document variability so the foundation design reflects actual field conditions.
How does the high expansion potential common in valley soils affect the scope of soils testing I should budget for?
Expansive soil behavior is characterized using the Expansion Index test per ASTM D4829, which classifies soils from very low to very high. For sites with moderate to high results, the geotechnical report will typically recommend pre-saturation, select fill import, deepened footings, or post-tensioned slabs. Budget for multiple expansion index samples across the site when soil color, plasticity, or Atterberg limit results suggest clay-rich materials.
Which office covers geotechnical in San Bernardino County, CA?
Field work in San Bernardino County is dispatched through the Los Angeles, CA regional hub, about 55 miles away. Laboratory testing is performed in Sugar Land, TX under chain of custody, or in a mobile laboratory mobilized to large San Bernardino County projects.
Are the technicians you send to San Bernardino County certified?
Field sampling and testing in San Bernardino County are performed by our ACI- and NICET-certified technicians. Geotechnical engineering and professional services are delivered with professionals licensed in California, coordinated under one proposal.
Scheduling & proposals
Need geotechnical engineering in San Bernardino County?
Call to schedule a technician, or send project documents for a written proposal.