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, LSI Adapt, Inc. <br /> Structura!Fi!! <br /> Thc following commcn[s, rccommcndati�ns, and conclusions rcgarding structutal fill arc provided for <br /> design and construction purposes. <br /> Materials: SVucmral fill includes any fill materials placcd under footings, pavcments, driveways, and <br /> other such structures. Typical materials used for sWetural fill include: cican, well-gradcd sand and <br /> gravcl (pit-run); cican sand; crushcd rock; controllcd-dcns''v fill (CDF); Ican-mix concretc; and various <br /> soil mixtures of silt, sand, and gravel. Rccycled concrcte, asphalt, and glass, dcrivcd from pulverized <br /> parent materials may also be used as strucmral fill. <br /> Placcment and Comoaction: Gencrally, CDF, and lcan-mir concrete do not rcquire special placemcnt and <br /> compaction proccdures. Tn contrast, pit-run, sand, crushcd rock, soil mixmres, and recycled matcrials <br /> should be placed in horizontal lifis not cxcecding 8 inchcs in loosc lhickness, and cach lift should bc <br /> thoroughly compacted with a mechanical compactoc Using the modificd Procbr maximum dry density <br /> (ASTM: D-1557) as a standard, wc recommend that structural fill used for various on-sitc applications be <br /> compactcd to thc following minimum dcnsitics: <br /> Fill Aaplication Minimum Comnnction <br /> Slab/Footing subgradc 90 percent <br /> Grsvcl drive subgradc(upper 1 foot) 95 perecnt <br /> Gravel drivc subgradc(Uclow 1 foot) 90 perccnt <br /> Subgraucs and Tcstina: Rcgardless of location or material, all strucmral fill should bc placed over 6rni, <br /> unyiclding subgrade soifs. Wc rccommend that a rcprescntativc 1'rom Adapt bc rctained to obscrve thc <br /> condition of subgrade soils Uefore fill placcmcnt begins, nnd to perCorm a scrics of implace density tests <br /> during soil fill placcmcnL In this way, thc adcyuacy of soil compaction efforts may bc cvaluatcd as <br /> carthwork progrc�ses <br /> Fines Contcnt: Soils used for structural fill should not contain individual particics greatcr than about 6 <br /> inches in diameter and should bc frcc of organics, dcbris, and othcr dcletcrious materials. Givcn thesc <br /> prercquisites, thc �uitability of soils used for structunl fll dcpcnds primarily on the grain-sizc disfibution <br /> and moishtrc content of thc soils when thcy are placcd. Whcn the "fines" conlcnt (ihat soil fraclion <br /> passing the U.S. No. 200 Sicvc) incrcascs, sails become more sensitivc to small changes in moisturc <br /> contcnt. Soils containing morc than about 5 percent fincs (by wcight) cannot bc consistcntly compactcd <br /> to a firm, unyiclding condition whcn the moisrore content is more ihan about 2 percentagc poinls abovc <br /> optimum. The ncar-surface, and dceper silty sand should be considered highly moisture scnsitive. The <br /> use of"dcad' soil is nccessary for fill placcment during wct-weathcr sitc work, or if thc in-situ moisturc <br /> content oF the sandy site soils is too high to allow adequate compaction. Clcan soils nrc �cfincd as <br /> granular soils that l�avc a fincs conlcnt of Icss th�n 5 perccnt (by �vcight) bascd on thc soil fraction <br /> passing thc U.S. �'4-inch Sic��c. <br /> Neztel Uo Tutra Tech June 25,2004 <br /> . LSI Adapl Project No.WA04-11499•GEO Page 1]/ <br /> / � <br />