1600 121ST ST SE 2016-01-01 MF Import

Deccmbcr 15, 1992 11 923-1184 5.7 Fill Requirements The native lill soil is acceplable (or use as siruclural (ill provided it does not become too �vel due lo nahiral moislure conlenl(�roundtvaler) or rain(all. The exisling (ill encuuntered in ottr lest pils �cill generally be suilable for stniclural fill provided it can be properly moisture conditioned and any debris or organics are renioved. During wet weather all of the ornsile soils tvill bc difficull if nol itnpossible to use. Due lo Uic required grading, off site borrow will be required. Imporled fill should be comprised of a clean, fine-draining sand and gravel fill wilh Icss than 10 percent passing the No. ?AO sicve. Durin� exlended dry periods, il uiay br �,ossible to use borrow wilh more (ines if Ihere is a signi(icant cost advanlage. lYc recommcnd lhat grading nol be allempled in wct �vcalhcr. During exlended wcl periods, (ills with 10 percent (ines can br. di(fictdl lo place and cofnpacl. To insure continued o��ci:ition during tvcl periods, if necessary, we recommcnd u.sin� a coarser, frcc-drainin� sand and grevel fill material. Thc fill rnatcri�l shoulcl bc tvell gredrd and conlain Icss than 3 percent passin� the No. ?AO sievc, based on Ihc minus �/4-sievc fraclion. 7'his lypc of matcrial can lypically be plamd and compacled in wet wealher conditions. Oversize pibrun material may be necded ta proviJc a slabilizing base coursc in wel arcas or lhc usc of �eolexlilc separation fabrics may be rcquircJ. Any fill placed bencall� foolings, floor slab, or pavement arcas should be placed in tnaxinuun eight-inch thick loose li(ts, moislure-condilioned lo near oplimum moislure contenl, and compacted to al least 95 percent of ASTM D 1557, Modified Proctor. Pill placed benealh sidewalks or ather slructural componenls such as over-excavaled ulility service lrcnches shoulJ be compacted lo al leasl 90 percent of AS7'M D 1557. If densily lesls indicale mm�»clion is not being achieved, Ihe fill should be scarified, moislure-condilioned lo near oplinwm moislure content, rrcompacled, and relesled. 5.8 Drainagc I'rovisions Wc recomnund both shorl and long tcrm drainagc mcasures be incorporaled inlo Ilic projecl design and construclion. Of major concern would be the ponding or discharge of sur(ace waler during conslruclion since Ihe fill, peal and nalive lill soils are highly lo mod�rately moistum sensitivc. To minimizc thc pofenlial for surfacc waler damagc to Ihe subgrade, il is recommended lhal all grading operelions bc per(ornmd in lhc drycr, summer monlhs. Not only is rainwalcr diminished at Ihis limc but the local �roundwaler tablc should alsu be depressed. roundalion cxcavalions extending to nalivc soils Ihrough Ihe exisling fill and peal should implement temponry sumps to inlerccpl groundwater and prevent degradalion of the exposed subgrede and freshly puured concrcte. Surface runoff can be conlrolled durin� conslruclion by carcful grading praclices. Typically, Ihene include lhe conslruclion of si�illow upgradc perimeter dilches or low carlhen bcrms and lhc use o( temporary sumps to collccl runoff and prevenl water from dama�ing sloprs and exposed subgrades. All collected water should be directed under control to a posilive and permanenl discharge syslem such as Ihe slorm sewer. Permanent conlrol of polenlial overslope discharge of surface waler should be incorporated in the (inal �radin� design and t�e�;elalive proleclion shotild be eslaUlished. Goldcr Associales