Mendocino Community College retained LACO to conduct both geologic hazards/geotechnical evaluation and construction materials testing and inspection services for a 31-acre parcel. The site was developed with a total 10,000-square-foot facility consisting of three buildings, driveways and a parking lot, concrete plaza/walkways, underground utilities, and associated landscaping in Lakeport, California. Related improvements included widening Parallel Drive fronting the parcel.
Our project team conducted literature review, geotechnical exploration, laboratory testing, engineering analysis, and field observations/testing during earthwork to assess site soil-profile and subsurface conditions for suitable support of the relatively heavy building loads. LACO’s Professional Geologists and Geotechnical Engineer conducted geotechnical and geological hazards evaluations to support design and construction of the project. They performed subsurface explorations utilizing cone penetration test (CPT) and rotary-wash geotechnical drilling equipment. LACO’s project team analyzed soil samples collected during the evaluations for classification, strength, and corrosion characteristics.
Our findings indicated that the project was feasible as proposed, but with a major risk of significant settlement of the site soils during earthquake-induced liquefaction. LACO presented a report with results from the geotechnical/geological evaluations and a laboratory testing program to the design team for their use on the project. The California Geological Survey under contract to the Division of the State Architect (DSA) reviewed and approved our report. The design team utilized rigid reinforced mat slab foundations, which they designed to adequately support school buildings, and to reduce post-liquefaction differential settlement to tolerable limits.
Following completion of our geotechnical/geologic hazards investigation, our Professional Engineers and Certified Technicians provided materials testing and special Inspections during the construction phase of the project. Special inspections and testing included concrete, steel reinforcement, high strength bolts, post-installed anchors, field/shop welding, and soils. We responded to all requests for testing and inspection within 24 hours of notice.
LACO provided cement treatment recommendations for the site surface soils in order for the project to incorporate this stabilization treatment of the site soil to allow wet-weather construction. Thus, construction was able to proceed without significant extra costs and/or delays during the rainy season. Throughout the project, we responded quickly to our client’s needs, and provided multidisciplinary support services to support the project’s success. We completed all aspects of this multidisciplinary project on time and on budget.