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� <br /> � Mr. Charles Thompson <br /> � Project BL-04-05907 <br /> � October 27,2004 <br /> � Page 12 <br /> � <br /> � <br /> D. Construction <br /> � <br /> � D.1. Observations <br /> ■ A geotechnical engineer should observe the excavation, footing and slab subgrades to evaluate if the <br /> , <br /> subgrade soils are similar to those encountered by the borings and adequate to support the proposed <br /> � construction. Oversize of excavations below perimeter footing grades should be checked. These <br /> � observations should be conducted prior to placing backfills, fills or forms for footings. <br /> � After excavating for footings,we recommend that tests be conducted on the subgrades to evaluate if the <br /> � bearing capacity is at least 3,000 psf. Typical insiruments used for these tests include hand augers, <br /> ■ penetrometers and sample tubes. <br /> � D.2. Backfills and Fills <br /> ■ Site soils,which will be excavated and reused as bac�lls and fills appear to be near estimated optimum <br /> moisture content. It may be necessary to moisture-condition these soils depending on conditions at the <br /> � time of construction. <br /> � <br /> ■ D.3. Testing <br /> We recommend density tests of backf"ills and fills placed beneath footings, slabs and field areas. Samples <br /> � ' of proposed backf`ill and fill materials should be submitted to our testing laboratory at least three days <br /> ■ prior to placement for evaluation of their suitability and determination of their optimum moisture <br /> contents and maximum dry densities. <br /> � <br /> � <br /> E. Procedures <br /> ■ <br /> � E.1. Drilling and Sampling <br /> � We performed the penetration test borings on August 17, 18 and September 9, 2004, with a core and <br /> auger drill equipped with 3 1/4-inch inside diameter hollow-stem auger mounted on an off road floatation <br /> � tire and truck drill rig. Sampling for the borings was conducted in general accordance with ASTM D <br /> r 1586, "Penetration Test and Split-Barrel Sampling of Soils." We advanced the boreholes with the <br /> hollow-stem auger to the desired test depths. A 140-pound automatic hammer falling 30 inches was then <br /> � <br /> � <br /> � <br /> � <br />