Geotechnical Services
Leighton emerged as one of the earliest consulting firms of its kind in California. We have a long history of working in the public and private market sectors, and clients have since turned to us for our expertise to accomplish even their most complex projects. As a local pioneer in the field of geotechnical engineering and engineering geology, Leighton has been recognized and awarded for engineering excellence by the American Council of Engineering Companies, American Society of Civil Engineers, Association of Engineering Geologists, and California Geotechnical Engineers Association.
As an award-winning firm, clients trust Leighton to provide value engineering and innovative yet practical solutions. That is why over 80 percent of our business is from repeat clients. Having completed thousands of projects in the region, we have a vast historic and scienctific database containing geology and geotechnical information readily available and constantly utilized by our engineers and geologists - an added value to our geotechnical services.
Leighton provides a balanced team of licensed geotechnical engineers and engineering geologists experienced in identifying and mitigating geotechnical and geologic hazards throughout the southwestern United States. We look for cost-effective solutions you can build on, considering the risk of:
- Soft and/or compressible soils
- Moisture sensitive (collapsible and/or expansive) soils
- Slope and excavation stability
- Groundwater issues during construction and for permanent facilities
- Faulting and seismicity
- Secondary seismic hazards, such as liquefaction, seismically induced slope instability, lateral spreading, dynamic differential settlement, seiche and tsunami.
- Corrosive and otherwise chemically active soils
- Methane and other hazardous gases
We provide all of the necessary geotechnical services required for a project which commonly fall into the following phases discussed below:
Preliminary Planning and Land Use Decisions
Design Phase
Observation, Instrumentation and/or Testing During Construction
Forensic Geotechnical Engineering and Distress Investigations
Preliminary Planning and Land Use Decisions
Leighton’s most effective involvement in any project begins during the early planning stages. We help our clients develop a land use or construction plan that maximizes the opportunities that their project site offers. As a result, well-planned projects run more smoothly and are more profitable. During this phase, we provide the following:
- Desktop geotechnical feasibility and due diligence studies
- Geological input for preparation of EIR/EIS documents
- Geologic and seismic hazard evaluations for planning input
- Design criteria and support for construction permits
^ back to top ^
Design Phase
Leighton supports a project during the design phase with a detailed geotechnical site investigation. To develop design parameters that mitigate the project constraints, meet regulatory requirements, and can be implemented efficiently, we first determine subsurface geotechnical conditions by drilling and sampling onsite soils. Our studies are generally designed to provide the information needed for specific project decisions, determined by either our client team of engineers and contractors, or the regulatory agencies that provide site permits.
Leighton's studies may include:
- Evaluation of geotechnical constraints and opportunities
- Subsurface geotechnical studies to characterize site conditions, and the suitability of onsite soils to support building construction
- Design parameters for foundations and building structures
- Laboratory testing for soil and rock properties
- Analysis of slope stability and seismic shaking hazards
- Remedial earthwork designs to mitigate or eliminate geotechnical constraints
- Calculation of interim remedial earthwork volumes for project costing and bidding purposes
- Investigation of groundwater conditions, including monitoring, sampling, testing, and predictive modeling
- Interface with regulators of the appropriate review agencies
^ back to top ^
Observation, Instrumentation and/or Testing During Construction
During construction, our work typically consists of geotechnical observation and testing of the field activities being undertaken by the client’s contractor. Our objective is to be in conformance with the project specifications and the regulatory requirements of the permitting agencies. Our ability to solve field problems quickly and effectively keeps field costs under control, while confirming that the contractor is meeting the job requirements. The foundation and utilities subcontractors work closely with our engineers and technicians to provide for a competent building foundation, and to confirm that the building ad is in accordance with the foundation recommendations and specifications.
During this phase, we may be responsible for:
- Geotechnical observation and testing during site grading and/or construction
- Instrumentation for monitoring settlement and temporary slope stability
- Rapid response to unexpected site conditions through design modifications
- Geologic mapping and approval of excavations
- Groundwater monitoring and testing
- Confirmation testing of soil and rock in the laboratory
- Certification of conformance with project specifications based on available testing and observations during construction
^ back to top ^
Forensic Geotechnical Engineering and Distress Investigations
For existing earthwork and structures, Leighton can evaluate distress related to geotechnical conditions. This typically may include:
- Geotechnical and/or geologic reconnaissance and photo-documentation
- Floor-level (manometer) surveys, installation of crack monitors and/or other instrumentation
- Slab-on-Grade Moisture Vapor Emission Rate (MVER) testing
- Subsurface exploration and geotechnical laboratory testing
- Evaluation and consulting, and meetings to discuss our findings
- Report preparation, as needed
^ back to top ^
