Item 17 - Agreements for On-Call Geotechnical Engineering Services

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• At the completion of our field investigation, the explorations will be backfilled in accordance with County guidelines and patched to match existing surface conditions. Drill cuttings may need to be stored temporarily on- site, in clearly labeled 55-gallon drums, pending soil characterization and disposal at an appropriate receiving facility. LABORATORY TESTING Leighton has three laboratories (Irvine, Temecula and San Diego) with an extensive inventory of equipment and cross -trained staff that can handle many types of samples and tests. Our ability to load -level our tests between laboratories allows us to accept large volumes of samples and be more responsive to our client's needs when rapid turn -around times are needed. We perform a full spectrum of geotechnical soil testing in-house, including, but not limited to: • Moisture/Density • Direct Shear • Compaction • Specific Gravity • Triaxial Shear • Expansion Index • Particle Size Analyses • Consolidation/Swell • Falling/Constant Head Permeability • Atterberg Limits • Stabilometer (R-value) • Corrosivity The following is a list of common tests for aggregate, hot mix asphalt (HMA) and Portland cement concrete (PCC) that Leighton performs in our laboratories on a regular basis. AGGREGATE (HMA & PCC) • Sieve Analysis • Specific Gravity (Coarse/Fine) • Sand Equivalent • Durability • LA Rattler • Soundness (Sodium/Magnesium) • Organic Impurities HOT MIX ASPHALT & PORTLAND CEMENT CONCRETE • Maximum Density - Hveem • Concrete Cylinder Compression • Flexural Strength of Concrete • Bulk specific Gravity of Compacted HMA • Asphalt Extraction by Ignition • Theoretical Maximum Density/Specific Gravity • Wet Track Abrasion of Slurry Seal The quality of our laboratory is controlled using certification programs from the City of Los Angeles Department of Building and Safety (LADBS), AASHTO Materials Reference Laboratory (AMRL), California Division of the State Architect (DSA), Caltrans (various districts), among others. The quality of our analyses is controlled using verification forms that require stand-alone, fully reviewed engineering calculation packages to support design recommendations. REPORT AND FINDINGS We will prepare a geotechnical design report in accordance with the 2022 California Building Code and appropriate regulatory agencies guidelines and requirements. The report will contain graphics and discussions presenting our findings, conclusions, and recommendations for the project. The report will be signed by a California -licensed Geotechnical Engineer (GE) from our firm. Generally, our report will provide the following: Subsurface Conditions: A discussion regarding the encountered subsurface soils conditions including soil type, in -situ moisture content and density, and depth to groundwater Geologic Hazards: We will discuss potential geologic hazards at this site, including potential for surface fault rupture, ground shaking, liquefaction, lateral spreading and differential seismic settlement, and potential flood hazards at the site using available data. Seismicity: We will provide a regional fault map showing the proximity of this site to major faults identified by the California Geological Survey within a 100-kilometer radius of the site. We will also perform a site -specific ground motion analysis to obtain site -specific seismic coefficients in accordance with ASCE 7-16 and the 2022 California Building Code (CBC).