4902 SEA BREEZE WAY 2016-01-01 MF Import

JW ta 06 03:07p GBT Construdion INC JUL-14-2006 FRI 0]�53 Pn H419 GeCSCIENCFS )uly 14, 2006 HWA Projocl No. 20U6-000-21-T054 4255140652 FaK h0. 4257742714 Curn:ntly, no si��s of prescnt ur imminent instability were obscrvcd on lhe slope below the residcuce. Ho�vcvcr, the slope is not hcavily vegMated and lhe primary covcr is ivy, wliich dnes not provide for a high levcl of stubilizing influmcc. Sorne vine muple trccs e�ist nwr thc top of the slope axijoining the building foolprint and some older conifcr vecs occupy the lowcr cr.stem put of 4ie siee, 77�e maple Uccs wae observed to have severely distocted, pistol•butt sh�ped, tnrnks that is indicalive of significant surficiaF cncp of slopc soils with timc. No evidcncc of ground water secpage was cvident within lhe foundation cxcavatton urea �r on thc slopc facq although the laller is largely obscurcd by ivy ground cover. Thc a+ccavation walt on the west side of thc sW cture was observcd to bc somcwh�t damper than the othcr portions of the cxcavatiun and may be attributnble to lawn und siuubbcry �vntcring on Ihc adjacent lot. COrCLUS10NS AND RF,COMMENllA'IIOhS Bnscd on our a,.sessmeut, wc concludc �hat the slope betwccn thc sin�cture and Mukiltw Rnulcvard docs not havc a high levd of stability uith respect to n shnllow skin-type slide cvcnt, nllhough immedistc failurc is not likely to occur as a consequence of the housc cmistructian. Significant creep defm•mation ofthe s�rficial soil laycr has bcen guing on with [ime anJ is readily appucn(. Mountnin beaver activity is contributing to furt}:cr slupc soil looscivng and U�cir burrows cau providc for addition�l infiltration paths fiir dircct prccipitalioa ;uiJ runoff cntry. These r.onditious servc to rcduce stability with Nmc. Moreover, shotild s lergc scalc earthquake occur in thc futwc, this could Vi�cr a slide of suficial slope materials. Accordingiy, it is our view tl�at an cicmrnt ofrisk cxists in thc Inng-tenn that a shallow (3 to 5-foot deep) skin slide could occur on this slope and could uudcnnine a sl,allow footing foundaGon in close proximity ofthc slope. This, ofcourse, would ]ead to loss of sup�prt foi t}�at portion of the structure bcing supportcd by tha footing nnd significxnt settlement would oewr. lmmediate and eatestrophic wlfapse nf tlie structure would not be a�ticip�led to occur, but Ihe slructurc could be rcndcrcd in nced ofmajor npair and uninhabitablc in 'ac near-fenn after such nn occurrence. A�cuming that the City of Everr,tt will a11ow construction to wntinuq in light ofexisting siic condit;o�s, anJ tlee owncr is pny;ved to accept lt�e risk of potealial futurz slope instability and its ncgativc consequen�;es to the structurq it is our �9ew that thc swc(ure can t+e cons;cuctcd as designul. Ilowcvcr, to mitigate the negntive effccts af a potentia{ slopc failurc on thc foundation systcm, it is our recommcndarion to suppnrt the perimettt wall nf the structure that adjoins the slope on a pilc foundation system. !f pilc foundation supFu�rt is opted !'or, wc recommend that it eztend along and be adopted for ihe entiru north perimc[cr ws1] inclu�ing jog section. Thc rcmaining secfions o: perimetcr footing cxtrnding from this wal[ and back of �he slope may be constr�ctcd on strip footings, as curmitly dcsigncd and laid out in the ficld. We rccommcnd that the �sux ses onv,.. w��. p.1 P. C4 H1YA GkUSC1ENCE51\C.