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i <br /> � • Lateral loads may bc resisted by friction on ihe basc of footings and the slab and passive <br /> rcsistancc on the sidcs of the footings. Prictional resistance may be determined using 0.4 for thc <br /> Icocf7icicnt of basc friction. Passivc resistancc may be detertnincd using nn equivalent Ouid <br /> i dcnsiry of 300 pounds per cubic foot (pc� wherc adjaccnt soils cansist of structural fill, and <br /> 450 pcf whcrc thc adjaccnt soils consist of densc glacial till. <br /> j • Wc mcommend a basc coursc br. utilizcd bcneath new slab-on-gmde sections or bcncath ncw <br /> PCC pavcmcm. Thc bnsc course should consist of a minimum of 6-inches of '/.-inch-minus <br /> crushcd rock and cumain no morc than 5 perccN fines content (that portion passing the U.S. <br /> No. 200 sicve). All loose soils should bc rcmoved from the excavation and the subgredc should <br /> te compactcd and evaluatcd by thc gcotcchnical cnginecr prior to placing thc recommendcd base <br /> layer. We rccommend a subgrade modulus of 150 pounds per cubic inch (pci) for lhe slab <br /> Isupportcd on thc rccommendcd basc ovcrlying Ihe existinn fill prcparcd as recommendcd above. <br /> • Wc rccommcnd Sitc Clnss C in accordancc with I[3C 2006 bc utilizcd for scismic dcsign. Dascd <br /> I on thc soil consistcncy and groundwatcr table, ihe subsurfacc soils are not susceptible to <br /> liaucfaction. <br /> I SITE PREPARATION <br /> Sitc improvcmcros will requirc rcmmal of a portinn of cxisting slabs, and �tentially buricd utilities <br /> prescnt at thc silc. Thc undcrlying fill and glucial lill soils �ssess high fincs (silt) contcN such that <br /> rcpcaicd construction iraffic could rcsuh in considcmblc disturbance during wct wcalhcr conswction. <br /> Wc suggcst Icaving thc existing asphall concrctc to protcct thc subgradz during construction whcrc <br /> practical. <br /> Wc r�eommcnd cxpo.^.^.d suhgrades for thc new eNranccs bc prouGolled with heavy rubber-tired <br /> cor.struction equipment if work is donc during cxtended dry weather. My soft, loose or othcnvisc <br /> ( unsuitable arca. identificd during proofrolling should be recompacted, if practical, or rcmoved and <br /> repluccJ with slrucwral fill as described subsequently. Wc recommend that proofrolling of the subgrade <br /> bc obscrvcd by a rcprcscNativc from our firni to assess thc adcquacy of thc subgradc conditions and to <br /> I idcntify nrcas nccding rcmcdial wark. If canswc�ion is perfortncd during wct wcathcr, we rccommcnd <br /> thc cxposcd subgrndc bc cvaluatcd by probin�. <br /> EARTHWORK AND E%CAVATIONS <br /> General <br /> A minor qumility of ncw fill µ�ill hc rcyuircd fur grading m thc ncw entranccs and backfill against ncw <br /> fiiolings anJ suh� -facc lacilitics. Wc rccommcnd all ncw fill bc placed and compacicd as slructural fill <br /> as Jclincd in d�, :cpnrt. Iixcavalions will bc required for utility trenchcs and we understand an <br /> approximntc 7doot-dccp cxcav�tion will bc rcquircd dunng modifications to Building C locatcd within <br /> thc cxisting Kasch Park Rasc. <br /> Excavallons <br /> 1•:xca�alions within thc lill can bc accomplishcd wiih convcntional excnvating cquipmcnt. Exwvation in <br /> Ihc glacial lill soils will bc morc ditficult und may rcquirc hcavy npping or thc usc of hoe-rnms to <br /> It:�cililate ihc trenching. We expecl thal conventional hea�y excavators will be adequate to excavate site <br /> soils up to about 20 I'cc� in dcpth. 7�he contraclor should bc preparal to rcmove cobbles and bouldcrs <br /> Iwhich arc f}cqucntly cncountcrcd in thc glacial till dc�sit5. <br /> I Pilr Nn.7U44q14.IN Pag!I �7EOENGIMEEIIS� <br /> llac 11.11N14 <br />