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<br /> <br /> 5 Parsons-1-01 <br /> <br /> <br />recommendations for the Proposed Dwelling Unit are based on observations from the field <br />investigation program and the physical test results. <br />7.1 EARTHWORK <br />All earthworks, including excavation, backfill and preparation of subgrade, should be <br />performed in accordance with the geotechnical recommendations presented in this report and <br />applicable portions of the grading code of local regulatory agencies. All earthwork should be <br />performed under the observation and testing of a qualified geotechnical engineer. <br />7.2 SITE AND FOUNDATION PREPARATION <br />All site preparation should be observed by experienced personnel reporting to the project <br />Geotechnical Engineer. Our field monitoring services are an essential continuation of our prior <br />studies to confirm and correlate the findings and our prior recommendations with the actual <br />subsurface conditions exposed during construction, and to confirm that suitable fill soils are <br />placed and properly compacted. <br />The site fill material is considered undocumented and may not be suitable for support of the <br />new footings. We recommend that the upper 3 feet of existing soils be removed and <br />recompacted. Lateral extent of overexcavation is 5 feet, where possible. If loose, disturbed, or <br />otherwise unsuitable materials are encountered at the bottom of excavation, removal of <br />unsuitable soils will be required until firm soils are encountered. <br />Excavations below the final grade level should be properly backfilled using lean concrete or <br />approved fill material compacted to a minimum of 90 percent of the maximum dry density as <br />determined by ASTM Test Method D1557. The backfill and any additional fill should be <br />placed in loose lifts less than 8 inches thick, moisture conditioned to near optimum moisture <br />content, and compacted to 90 percent. Fill materials should be free of construction debris, roots, <br />organic matter, rubble, contaminated soils, and any other unsuitable or deleterious material as <br />determined by the Geotechnical Engineer. The on-site soils are suitable for use as compacted <br />fill, provided the soil is free of any deleterious substance. All import fill material should be <br />approved by the Geotechnical Engineer prior to importing to the site for use as compacted fill.