1901 MERRILL CREEK PKY 2018-01-01 MF Import

In addition to wall and footing drains, installation of subsurface drainage measures (e.g., interceptor ditchu) may be appropriate at the site. We recommend that a geotechnical engineet observe and evaluate actual soil and grouc�t water conditions encountered during grading activities to determine where additional drainage measures are appropriate. Interceptor ditches are discussed in a folluwing section "Drainage Considerations." I Structural Fill � Structural fill will bc required to form portions of the buiiding pads, around the perimeter � ' of building walls,and to bac�ll utility trenches. Some structural fill may also be required where r-;. p�rking azea grada aze raised and to bac�ll localized excavations oaaide of the buildings. All �. structural fill material should be free of otganics, d:bris and other deleterious material with no individual particles lazger than 6 incha in diameter. Most of the native soils contain a significant amount of fines and will be suitable for use az structural fill only during dry weather. As the amount of fina (that portion pazsing the U.S. No. 200 sieve) increases, the soil becomes increasingly scnsitive to small changes in moisture � content and adequate compaction becomes more difficult or impossible to achieve, particularly �.'.. during wet weather. Therefore, we recommend cocutcuction occut during the drier summer :� months to help reduce earthwork costs. The moisture cuntent of most of the near-surface soils appears to be near the optimum moisture content required for compaction at the time��f our field � work in mid-September. Therefore, they will be suitable for use as structural fill during the summer and early fall season. �,� If wet weather construction occurs, reese of excavated soils will not be practical. If wet weather construction ocwrs, we recommend that an import soil containing no more than about 5 percent fines by weight be used in structurat fills. A portion of the on-site sandy soils (those j classified as SP-5M or SP) may also be suitable during wet weather conditions. Wet weather construction may also require the use of a layer of crushed rock or quarry spalls for constnution haul roads, and as a working surface on the proposed building pads. We recommend that all fill used in building and parking areas be placed and compacted as ' structucal fill. The fill should be placed in horizontal lifts generally not excadit►g 10 inches in loose thicimess and uniformly compactcd. Where fill is placed on existing slopes at the site, the fill should be keyed into the native slope face by ezcavating a series of horizontal benches. The benches should be a minimum of 3 feet wide cut into the slope gradient. All fill placed below footing grades, as floor slab subgrade, and within 2 feet of top of pavement subgrade levels should be compacted to at least 95 percent of the maximum dry density (MDD) as determined in accordance with the ASTM D-1557 test procedure. Fill placed deeper than 2 feet below the pavement subgrade should ��e uniformly compacted to at least 90 percent of Uu MDD. It is critical that any structural fill on which footings will be supported be prepared properly to limit settlements. We recommend that all footi�g excavations and fill placement be obucved G e o E n � i n e e r s s Fiie No. U60-006�73-11701111297