California Department of Transportation




Office of Geotechnical Support

The Office of Geotechnical Support serves the Geotechnical Design Offices, Structure Design, and Structure Construction through specialized engineering geologic services, field instrumentation, pile testing, and laboratory testing of soil and rock samples.

The Office consists of four branches and one special program:

  • Foundation Testing and Instrumentation Branch
  • Geotechnical Laboratory, Graphics, and Records Branch
  • Geophysics and Geology Branch
  • Drilling Services Branch

Doug Brittsan
Phone : (916) 227-7004
Fax: (916) 227-7075



Foundation Testing and Instrumentation

Jason Wahleithner

(916) 227-1059

Geophysics and Geology

Bill Owen

(916) 227-0227

Geotechnical Lab, Contracts, Graphics, and Records

Lilibeth Purta

(916) 227-5239

Drilling Services Mike Morgan (530) 210-0127
  Xing Zheng (916) 227-5863


Foundation Testing and Instrumentation Branch

The Foundation Testing and Instrumentation Branch provides statewide foundation testing and geotechnical instrumentation services, including:

  • Pile load testing
  • Pile driving analyses
  • Nondestructive testing
  • CIDH Pile Mitigation Review
  • Pile drivability studies
  • Sonic Caliper Testing
  • Slope Inclinometer Testing
  • Cone Penetrometer Testing
  • Automated landslide monitoring stations

Geotechnical Laboratory

The Geotechnical Laboratory is an AASHTO Materials Reference Laboratory (AMRL) accredited facility located at the Transportation Laboratory in Sacramento. The Geotechnical Laboratory performs geotechnical testing of soil and rock samples for Geotechnical Services.

Engineering Graphics

The Engineering Graphics Unit produces log of test borings (LOTB) plan sheets and other drafting products required to support PS&E development.

Geotechnical Records

The Geotechnical Records Unit maintains the Geotechnical Services Archive (GeoDOG), which houses geotechnical information such as geotechnical reports, laboratory and field test results, and LOTB.

Geophysics and Geology Branch

The Geophysics and Geology Branch assists the Geotechnical Design offices with geologic data and recommendations using advanced geophysical testing methods.

Drilling Services Branch

The Drilling Services Branch provides statewide drilling services for Geotechnical Services (GS) and other Departmental functions such as Construction and Maintenance. Drilling Services operates standard and specialized equipment to handle the many unique and challenging investigations required to support the Department's mission.

Scour Critical Program

The Scour Critical Program provides geological and geotechnical support to the Office of Structure Maintenance and Investigations for bridges susceptible to scour, including:

  • Site visits to evaluate the threat of scour
  • Performing calculations for bridge foundations impacted by scour
  • Providing mitigation options for scour critical bridges
  • Recommending retrofit solutions for scour damaged bridges