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87�7I 66� 9T�80 3JI1 �'� <br />NEkTEL Communiqlions, Inc. <br />Aupust 16,1999 <br />Di6E TL8 9JZ�NOIltl�O'1 <br />9�91M-1312i-0 <br />Pape 3 <br />�,�, $�rface 4ondltlons <br />The project site is in a region characterized by rollinq terrain and commercial development. <br />Topography at the sile is relatively level in all dlrectionc with a moderately steep downward sloping <br />to the wast outside the communication leaae spaces. Vegetabon within the leased parcei is <br />negligible. <br />� Soll Conditions <br />Accorcii��g lo published geologic maps, soil conditions in the stte vicinity are charaderized by <br />�uaterr.ary deposits consisGng of Vashon till which aur on-slte exploretion generally confirtned. <br />3pedflcaliy, the soil proflle observed in boring B-7 consist�d �(:s niediW n tl:;nse, gtavelly sar� (hlll) <br />to a depth of 4'/: faef overtying some sod/topsoil and loose io mediurn dense, silty gravelly �and <br />to depth of 5'h feeL Below these layers, a dense gravelly sand with sane siH was encountered to <br />a depth of approximately 8 feet Vansilbning Into a very dense, silty gravelly sand (Glatial Till) <br />which extended to the maximum exploration depth of approximately 16 feet. <br />� Oroundwater Condltlons <br />At the tlme of exploratlon (August 10,1989), groundwater was not encountered withln our boring. <br />However, it should be noted, that groundwater levels rypically fluduate and may vary In response <br />to season, predpltation pattems, on- or off-slte construction adNldes, site utllizatlon, and other <br />faclors. <br />� Seismlc Condltlons ' <br />According to the Selsrlc 2one Map of the United Stafes contained in the 1997 Unifornt Bullding <br />Code, the proJect slte Iles within selsmic risk zone 3. Based on soll conditions encountared at the <br />site, we interpret the subsurface sfte condftlons to correspond to a selsmlc soil profile type S�, as <br />defined by 7able 16-J of the 1997 UnBorm 8uilding Code. Soll profile rype S� applies to a profite <br />consisting of predominantly very dense solls with a 3PT greater than FO bbws per foot wlthln the <br />uppertnost 100 feet in depth. Current (1996) NaUonal Selsmlo Hazarcl �!�aps prepared by the U.S. <br />Geological Survey indipte that a peak ground ecceleratioh ebout 0.3 :s appropriate for an <br />earthquake havirsg a 10-percent probablllty of exceed�nce fn 60 years (corres�anding to a retum <br />inierval of 475 yearsj. <br />4.0 CONCLUSIONS AND RECOMMENDA710N3 <br />The proposed eonstrucUon Is feasible from a geotechnkal perspecllve, yiven the subsurface <br />conditions dlsdosed in our field exploratlon. Our speciflc reoorr►mendatlons concemin8 ske <br />preparetion, equlpment shetter foundallon, and structural flll placement ere prasented in the <br />following sections.. <br />4,�, Slb Pre�uadon <br />Sfte preparaGon wNl Involve temporary drainage, stripping, preparing subgrades, and other <br />construcllon adlvitles. 1ire followfng comments and recommendatlons apply to sfte preparaibn. <br />s,�a,acwu Aaemw.n.�,poavo,n �rwna�i nvd� w..oa <br />siic #: �81MC�3 �It' H1,2143 V2�1V� fYdiS�Z � 66-9i-8 �A9 JAC�35 <br />