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i � <br /> Gec recluiirnl Enginccri�rg R pur� 1 Jwm?. �009 <br /> Conrnunih�NenllhCenfer. F.rerefl, IPA Projecf E!?009-(.ia <br /> I <br /> 3.0 SITE CONDITIONS <br /> I3.1 Surface <br /> l�hc sitc is a rectangular-shaped arca (tas parcels #00��17a?8803100. #OO�d7d'_'o802900. <br /> I and f�0047�d28801701) approximatcly I J4 acres in sira Thc site is bound to the north by <br /> Id'�' 3trcet, to thc west by an allcy, to tlie south by l�'h S�reet, and to the east by Broad�vay <br /> Avenuc. <br /> � Thc southcrn portion of thc sitc is currcnA}� occupicd by mcdical / hcalth scrvicc buildings <br /> and asphalt-paved parking lots. The northern portion of die site is a landscaping arca and a <br /> I small asphalt puvemenC Thc sitc is rclativcly Ilat with o��erall elcv�tion differcnccs of Icss <br /> than f ive feet. <br /> 3.2 Snils <br /> 7'he soils cncountcrcd in thc tcst borings arc relativcly consistent across lhc sitc. The <br /> typical suil protilc includcs 2 to 3 fcct of till ovcrlying mcdium densc to vcry dcnsc SAND <br /> with somc silt and tracc gravcl to silty SAND with grn�cl (glacial till). Thc lill consists of <br /> medium dense SAND wilh some silt and [racc gravel. <br /> IOur rcvicw of lhe Genlo�,�ic �1(np qJ' Ihe Ererrll Z.i-�1-/in�ue Qimdrnngle, Snnhornrsh <br /> Counq�, I�i�.�•hrn�,�ron by James P. Minard (198�) indicated that thc native soils wcrc <br /> I mupped as Vashon till (QvQ. The till is a nonsorted mi�ture of nwd, s�nd, pebbles, <br /> cobbles, and botddcrs (diamicton); it resemblcs concrelc mi�. These dcscriptions are <br /> gcncrally similar to ihc lindings in our licld csploration. <br /> IMore dctailed descriptions of thc subsurlace conditions encountered arc presentcd on thc <br /> "1'est [3oring Logs. �igures A? Ihrough A-7 in tlppcndix :�. <br /> I3.3 Groundw:�tcr <br /> Groundwatcr scepagc ���as cncountcrcd at l�l.> to Ij.2 fcct bgs in thc test borings dtving <br /> our tieW exploration. I�lucluations in growid�eatcr Ic��el should be expected on a seasonal <br /> anJ annual basis. Thc Ievel will bc highcst during the extended periods of he�vy seep�ge in <br /> the �vet winter months. Bascd on the amount of carth�vork expected, the ground���atcr will <br /> inot be .ncly lo aflec[ the project iCthe construction occurs in dry season. <br /> 3.d Scismic Considcrations <br /> Bused on the 2006 Intemalional I3uilding Code (I[�C), thc sitc soil is Class C (I'ablc <br /> 1613.�.2). Thc carthquakc spectral responsc acccicration at short periods (S,) is I I�.3% g <br /> Iand at 1-sccond perioJ (Si) is�10.3"/o g. <br /> Liquefaclion <br /> Liqucfaction is n phcnomcnon whcrc thcrc is a rcduction or comp! �te loss ol'soil strength <br /> dur to an incrcase in watcr pressure induced by ��ibration_ .rom a scismic event. <br /> The Riley Group, Inc. �� <br /> � <br />