Item 17 - Agreements for On-Call Geotechnical Engineering Services

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Central Jail Complex — Multiple Projects ORANGE COUNTY SHERIFF -CORONER DEPARTMENT I ORANGE, CA Working under an on -call contract with OCPW, Leighton provided geotechnical and/or materials testing services for a number of Orange County Sheriff -Coroner Department's (OCSD) projects at the Central Jail Complex (CJX) in Santa Ana. We provided on -call geotechnical engineering support, and observation and testing to confirm that placed fill materials including soils and aggregate base were suitable for the support of foundations, floor slabs, and new vehicular/pedestrian pavements. Observation and testing services were also provided during utility trench backfill operations and during asphalt paving operations. Engineering support and consultation provided by our onsite soils technician included remedial grading recommendations where loose or unsuitable soils for improvement support were encountered. Katella Facility Upgrades ORANGE COUNTY SHERIFF'S DEPARTMENT I SANTA ANA, CA 12019 — 2020: The Katella Range Upgrades project encompassed construction of a roof over the uncovered portion of the Range as well as expanding the Range to the north and south of the existing building footprint. The roof structure was constructed of structural steel with tapered steel girders and wide flange beams. The expanded area was enclosed by concrete masonry unit (CMU) walls, supported by reinforced concrete footings. Leighton performed a geotechnical exploration for the proposed improvements to evaluate the subsurface soil conditions of the site and percolation testing to assess infiltration rates of the soils for design of an onsite stormwater infiltration system. Because the site is located within an area identified by CGS as being potentially susceptible to the occurrence of liquefaction, we performed evaluations for liquefaction potential and provided in our report results of the analyses, including susceptibility of the site to liquefaction and seismically induced settlement. Leighton's geotechnical design recommendations were provided for construction earthwork, slab - on -grade and conventional shallow foundations, seismic design parameters in accordance with the California Building Code, lateral earth pressure parameters for retaining wall backfill, and setbacks of the stormwater infiltration system. Leighton also provided pavement design specifications for asphalt concrete and Portland cement concrete (PCC). Additionally, Leighton performed a geotechnical review to verify that geotechnical recommendations were properly implemented into the foundation and grading plans and water quality management plan. In support of construction, we conducted geotechnical observation and testing of earthwork operations as well as materials testing and inspection, including concrete sampling, structural steel welds, and plant tag and sample for rebar and masonry units. When asbestos containing materials, lead -based paint, and lead -contaminated items were removed from the project site, Leighton managed the air monitoring, sampling and testing services performed by Cal OSHA certified asbestos technicians and verified that removal and containment of hazardous materials were performed properly in accordance with applicable regulations.