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1)crenihcrl5, 1992 12 _ 923-1184 <br />We recommend fooling drains be included i( portions of Ihe floor slabs and/or (oolings are <br />below grade. Pooling drains should consisl o( a fuur-inch diameler, perfonted, rigid ��laslic <br />pipe embedded in a clean free draining sand and �ravel meeling Ihe requiremenls of Seclion <br />9-03.13 and Section 9-03.12(4) respeclively, o( the 1988 Washinelon Stale Stand�rd <br />��ecificitions for Road, f3ridge, ar�1 Muniripal Construclion. A�,�osilive means o( drainin� <br />lhc sub-slaU capillary break inlo Ihe drains should bc provi,led. Roof drains should be <br />connec�ed lo a separale syslem. <br />5.9 Conslruclion Considcralions <br />5.'11 Gencral <br />In �eneral, �eolechnical consiniclion tvill invoh�e Ihe placemenl of preload and surchar�;e fill, <br />installalion o( piles, placement and com��aclion of slruclural fills and pavemenf/slab subgnde <br />preparation. ll is anlicipaleJ that standard civil construclion methuds can be employed. <br />I lowever, due la ihe sensitivily of lhe sur(ace soils lo conslrucliun aclivilies, it is <br />rcconmicndcd lhat the major earlhtvork takc placc in lhe drycr, summer monlhs. 'Ihe <br />placenunt of preloacl/surcharge can occur during Ihe winler in order to minimize delays of <br />conslruclion due lo Ihe preload perioJ. Addilionally, Ihe contnclor must exercise exlreme <br />care to tninimize dislurbance lo ex��osed subgrades. 'I'hese and olher conslruclion <br />considerelions are discussed in delail belotv, <br />5.9.2 Pilc L�slallalion <br />In problem amas, il may be necessary lo staUilize Ilie groimd surface �vilh gravel or quarry <br />spalls lo �rovide equipmenl access. <br />We reconunend lhal a com��elenl pile drivin�; conlraclor Ue used (or Ihe pile inslallalions ' <br />since the �.rrformance of Ilie syslem is highly de�,endenl on Ilie conlraclor's experience and <br />inslallafion preclices. Addilionally, a qualified geotechnical engineer should observe the pile <br />installalions and documenl perlinenl dala to verify Ihat Ihe design crileria have been <br />salis(icd. Uue lo Ihe hard Iransition from peal lo lill, il is imporlanl Ihal Ihc piles nol bc <br />over-driven since they coulcl be domaged. <br />5.9.3 Subgradc Prcparalion nnd Proleclion <br />Througlwut Ihe sile sur(ace soils are highly to moderalcly moislure sensitivc and may bc <br />difficull lo excavale and plice tvhen �vet. 'I'his will be a parlicidar problem during wet <br />wealher or if surface water is present as conslruction activilies will easily disturb exposed <br />sub�rades. Gven in pile are�s, a reasonably firm base is desirable (or construction of tlie pile <br />ca�is and �raJe Ucams. hi addilion, in pavemenl arcas, a soflened subgrade will rcquirr. <br />ad�litional over-excavalion and replacemenl ivilh slruclural barkfill. l'hus, we recommend <br />lhat all carlhtvorks bc performcd in Ihc drycr, summcr monlhs and Ihat lhc conlraclor <br />exercise extreme care so as not lo dislurb or so(len subgra�les. It may be appropriale lo � <br />sfabilizc probletn areas by ��lacing a tvorking tnal of gravcl or quarry spalis in Ihc equipmenl <br />lracking lanes. Ceo(abrirs nny also bc usefid in subgradc slabilizalinn, <br />Golder Assocleies <br />