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�:-iafdidOi� ����`1�iLS0?�.INC. <br />10.13.3 rloor Slabs <br />Thc static ground�eatcr tablc is cxpcctcd to bc abovc thc proposcd slab clevation; <br />howcvcr, thc basc of lhc cxcavation may havc arcas that arc within thc dricr glaciolacustrinc <br />dcposits. Por long-tcrni groundwatcr control wc rccommend thc following. <br />� 1Vc rccommcnd a vapor barricr consisting of plastic shecting and a cican granular <br />matcrial bc placed undcr slab-on-gradc floors. Pigurc 7 prescnts vapor barricr location <br />� rccommcndations. Th^ pinstic shceting should bc placcd ovcr a capillary brcak consisting of at <br />Icast G inchcs of cithcr washcd pca gr.n�cl or properly compacted, 1.5-inch-minus crushed rock <br />���ith Icss than 5 perccnt passing thc No. 200 sicvc, by wcight, bascd on �act-sicving thc minus'/a- <br />, inch frxtion. Thc crushcd rock would likcly providc a firnur �eorking si�.rface for placing <br />rcinforcing stecl. <br />\Vc also rcconuncnd that subdrains bc inst.11lCd on e$O-(oOl giid S�acing undcr thc slab- <br />on-gradc. Subdrain pipcs should consist of 4-inch-diamctcr (minimum) perforated PVC and that <br />the pipcs be bcdded in U'enchcs 12 to 1 S inches decp. The subslnb drain ircnches should bc <br />backfilled ���ith washcd pca gravcl or dcan, 1.5-inch-minus crushcd rock. Wc undcrstand that <br />thc civil cnginccr, Rcid �9iddlcton, ���ill dctail thc subdrain trenchcs ro indudc n filtcr fabric <br />���r:ip. The filter fabric would line the subdr,iin trenches. 1Vater collected in subdrains should be <br />rrn�tcd to a sump or drain to thc stonn sewer. liandling potcntial ��round�eater contamin:uion in <br />thc subdrain systcm was dcscribcd prcviously. <br />A filtcr fabric or filtcr matcrial tnay bc rcyuircd bct���ecn thc capillary brcak gravcl/ <br />subdrains and thc nativc soil to reducc piping of finc-graincd soil up into Ihc gravcl. �Vc can <br />dctcnninc if a��ilter is rcquired once a proposcd gravcl gradation is provided, and oncc thc iloor <br />slab subgradc has becn c�posed. Gcncrally, a wcll-gradcd gr.n�cl �vould more likely bc sclf- <br />filtcring th:m a poorly-gruded (singlc sizc) gravcl. <br />10.14 I�ill Ylucemenl and Compuclion <br />Constn�ction of the Adminisuation Garagc �md ��rdcstri:m tunncl may rcquirc bacl:fill [o bc <br />placcd around building ���alls and footing cxca��ations and possibly for sidewalks. rctaining walls, <br />and utilitics. 1'hc on-sitc soils g�nerally contain sufficicnt fincs to make them moismre scnsitive. <br />In our opinion, thc on-site soils may be difficult ro placc and compact to adequate relati��c <br />com��action Ir��l�, cspccially �luring ��ct ��cathcr or in ���ct conditions. If thc on-sitc soil <br />: i. i-m�n�a ivs-e i,,.;.�u,� 2 I- I-096�1�7-005 <br />21 <br />