9 First American Way - Soils Report

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Lutzky Associates Development. LP - Geotechnical Invesiigation MACTEC Project 4953-03-2631 September 18, 2003 membrane. When grading is interrupted by heavy rains, fill operations should not be resumed until the moisture content and the dry density of the placed fill are satisfactory. Surcharge Fill (if necessary for shallow spread type foundation system) In order to reduce the anticipated static settlements to about '/z inch, we estimate that 10 feet of surcharge fill will be required. The footprint of the top of the surcharge fill should extend at least 10 feet beyond the footprint of the proposed Data Center which is about 150 feet by 150 feet, and the face of the surcharge fill should be sloped at 1 2: 1 (horizontal to vertical). The surcharge fills do not need to be compacted and tested, but should achieve a wet density of at least 110 pounds per cubic foot. The surcharge fill should be left in place for a period of at least 3 mohths. To verify the anticipated rate of settlement, we recommend that settlement markers to be set on the native soils and on the fill and sufficient readings be taken to confirm that the majority of the anticipated settlement has occurred prior to construction. Site Preparation After the site is cleared and any disturbed soils are excavated as recommended, the exposed natural soils and engineered fill should be carefully observed for the removal of all remaining unsuitable deposits. Next, the exposed soils should be scarified to a depth of 6 inches, brought to near-optimum moisture content, and rolled with heavy compaction equipment. At least the upper 6 inches of the exposed soils should be compacted to at least 90% of the maximum dry density obtainable by the ASTM Designation D 1557-00 method of compaction. Compaction Any required fill should be placed in loose lifts not more than 8-inches-thick and compacted. The fill should be compacted to at least 90% of the maximum density obtainable by the ASTM Designation D1557-00 method of compaction. The moisture content of the on-site clay soils at the time of compaction should be between 2% and 4% above optimum moisture content. The moisture content of the other soils should be between 2% below and 2% above the optimum moisture content. 31