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Page 2 <br /> <br />The site is relatively flat; and we understand that additional raw cut/raw fill is not <br />proposed for the site. <br /> <br />Geotechnical Conditions <br /> <br />Based on the published geologic map prepared by the California Division of Mines and <br />Geology (CDMG), the site is located within a broad flat alluvium and colluvium area. <br /> <br />Based on the State of California SEISMIC HAZARD ZONES Map, Newport Beach <br />Quadrangle, the subject site is located within a potential liquefaction zone. For <br />conservative purposes, we assume that the site will be subjected to liquefaction. <br />Therefore, a conventional liquefaction study with a 50 ft. deep test hole, and substantial <br />sampling and laboratory testing and engineering analysis for verification whether the <br />subject site is subject to liquefaction or is not considered necessary for this project. <br /> <br />To mitigate the potential adverse effects due to potential liquefaction, as for all other <br />near-by projects, a strengthened/stiffened foundation system [in accordance with the <br />Special Publication 117A (SP117A), “Guidelines for Evaluating And Mitigating Seismic <br />Hazards in California” dated 2008, published by California Geotechnical Survey (CGS), <br />page 60] will be recommended to be used for the proposed new structure. <br /> <br />The subject site is a previously graded lot where a house exists. The underlying soils <br />were previously properly treated, as necessary, and previously evaluated to be suitable <br />for structural support prior to approval for construction of the existing house. Distress <br />to the existing house due to settlement and/or any other geotechnical issues was not <br />observed / reported. Therefore, drilling a deep test hole, sampling, and performing <br />consolidation testing for evaluation of the potential deep-seated settlement of the <br />underlying soils is not considered necessary for this project. <br /> <br />To verify the near ground surface soils, a 5 ft. deep test hole has been drilled using a <br />hand-held drilling tool and soil samples were collected for laboratory testing. The <br />approximate location of the test hole is depicted on the Site Plan / Geotechnical Map. The <br />geotechnical boring log and summary of results of the laboratory testing are included in <br />Appendix B. <br /> <br />Based on the data of our test hole, the near ground surface earth materials generally <br />consisted of silty fine sand with some clay, dry, medium dense and have a very low <br />expansion potential. <br /> <br />It is noted that, for conservative purposes, current minimum code values such as an <br />allowable bearing earth pressure of 1,500 psf. and type 5 cement and 4,500 psi concrete <br />strength, etc. as well as remedial removal of minimum 3 ft deep are recommended for <br />this project. Deeper & wider footings with heavy reinforcement are also recommended to <br />be used for this project, Therefore, laboratory testing such as direct shear, grain-size <br />distribution, consolidation, sulfate content, etc. are not considered necessary and not <br />performed for this residential development project.