Item 17 - Agreements for On-Call Geotechnical Engineering Services

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e. Relevant Project ExperiencE Leighton has provided On -Call services for Geotechnical Engineering Services for various cities and public agencies across southern California. The list below highlights some of this experience in the past five years. Client Reference information for all of the client projects listed below are provided in section "g. References." Various Geotechnical Engineering Services ORANGE COUNTY PUBLIC WORKS1 SANTA ANA, CA BREA BOULEVARD CORRIDOR IMPROVEMENTS 12017 PRESENT: Leighton was selected competitively to provide geologic and geotechnical services for the widening of Brea Boulevard through Brea Canyon. The road widening will extend approximately 1.75 miles from Canyondale Drive to the Los Angeles County line. The project includes replacing three bridges; construction of earth retaining systems; extending several culverts; and construction new pavement sections. Bridge design was performed in accordance with AASHTO LRFD Bridge Design Specifications with Caltrans Amendments along with Caltrans Seismic Design Criteria. Earth retaining systems include conventional semi -gravity cantilever walls, internally reinforced systems including mechanically stabilized earth (MSE), earth anchor, soil nail and segmental block walls. Alignment of the road will also require the evaluation of slope stability for temporary excavations and permanent cuts. Pavement section design will be performed in accordance with the Orange County Highway Design Manual. ORANGE COUNTY ZOO LARGE MAMMAL EXHIBIT 12021 - 2022: Located towards the back of the zoo in the new Oak Woodlands habitat, the new large mammal exhibit consists of three new buildings: the Holding Building, Auxiliary Holding Building, and LSS-Kitchen Building. Working closely with the architect, our field exploration consisted of six borings to a maximum depth of 22 feet, a geophysical survey to support liquefaction analysis of the site, and a field percolation testing. We evaluated the soil characteristics, including expansion potential, corrosivity, shear strength and shear wave velocity, and geologic hazards at the site such as ground rupture, lateral spreading, and seismically induced settlement. Based on results of our analyses, we developed recommendations for design and construction of the project. During construction, we provided geotechnical observation and testing to confirm that placed fill was suitable for the support of foundations and floor slabs of the buildings and for the bioswale/filtration basin. We met with the general contractor, the County's arborist, and the grading operator when it was discovered that existing tree roots were in the path of proposed overexcavations, and that building and retaining wall footings would encroach underground drip lines for two oak trees and one pine tree. Special inspection and materials testing were performed during construction of the three buildings, bridge, cages, and canopy. Our tasks included special inspection and testing of reinforcing steel, concrete and masonry, ACI certified shotcrete, high -strength grout, ICC field welds, high -strength bolting, material identification verification of hardware, anchors and epoxied anchors and dowels, and shop NDT ultrasonic for complete joint penetration (CJP) welds.