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Geotechnical Engineering and Geological Hazard Study- Lincoln Elementary School Modernization Project Manteca, California Page 2 3. Tested soils recovered from the subsurface exploration to measure their pertinent engineering and index properties. The tests included unit weight and moisture content and dry density, sieve analysis, plasticity index, and R -Value. In addition, corrosion tests were performed on one discrete near -surface soil samples to evaluate the corrosivity of the soils to buried concrete and ferrous metals. Corrosion tests included pH, resistivity, water soluble sulfate, redox, and chloride tests. Laboratory test results are presented in Appendix C. 4. Analyzed the findings from the field exploration and laboratory testing to develop geotechnical recommendations for: a. General earthwork, including site stripping, subgrade preparation, temporary excavations, permanent slopes, trench backfill, import fill, compaction criteria, and site surface drainage; b. Foundation design and construction, including foundation type, allowable bearing capacities, lateral resistance, settlement, and foundation depth; c. 2013 California Building Code (CBC) seismic design criteria; d. Potential geologic and seismic hazards and recommendations for mitigation; e. Concrete slabs and exterior flatwork; and f. Asphalt and concrete pavements. Prepared this written report summarizing our findings, conclusions, and geotechnical recommendations. 3.0 SITE DESCRIPTION The Lincoln Elementary School site is located at 750 E. Yosemite Avenue in Manteca, California. However, most of the proposed new construction will be on the south side of the site, and near South Powers Street. The project site is generally rectangular in shape and relatively flat. The ground surface in most playground areas is covered with asphalt with the remaining field area covered with grass. The ground surface in and around the site has an average slope of less than I percent toward the west northwest. 4.0 GEOLOGIC AND SEISMIC SETTING 4.1 REGIONAL GEOLOGY The Lincoln Elementary School site is located in the upper San Joaquin Valley. Together, the Sacramento and San Joaquin Valleys form the Great Valley Geomorphic Province of California. The Great Valley lies between the Coast Ranges to the west and the Sierra Nevada Range to the east. The Great Valley is a northwest -trending, west -dipping geosyncline that has in -filled with as much as six vertical miles of sediment. Regionally, the lithology of the upper 3,000 feet of sediment within the Great Valley is derived from the Sierra Nevada range to the east and the Coast Range Mountains to the west. Locally sediments are 1,000 to 2,000 feet thick. The Coast Range Mountains generally consist of northwest trending ridges of Franciscan Assemblage and granitic basement rocks. The bedrock complex of the Sierra Nevada Mountains generally consists of metamorphosed sedimentary and volcanic rocks of Paleozoic and Mesozoic age (150 to 300 million years old) and plutonic rocks (chiefly granitic types) of Mesozoic age (80 to 150 million years old). Structurally, the Coast Range - Sierra Nevada Block Boundary Zone, a regional geological boundary separating Franciscan basement rocks of the Coast Range from granitic basement rocks of the Sierra Nevada Range, is present at depth near the western margin of the Great Valley Geomorphic Province. M Nk. CONDOR