1505 INDUSTRY ST Geotech Report 2018-01-02 MF Import

Uiility 7renches Trcnch ezcavation, pipe bedding, and Vcnch Lar.kiilling should be completed using the general procedums described in the Z004 WSDOT Standard Specitications or other suitable procedures specificd l,� d�e project civil engineec The �a[ive gl�cial deposits and fill soils encountered at the site are generally oi low corrosivity bascd on our cxperiencc in thc Pugc[Sound arca. I'tility trcnch backfill should consist oF stn�ctural fill and should bc plxed in lifis ol' 3 inchcs ar Icss Iloosc thickncss) such that adcqu�ue compaction can ba achicvcd throughout thc IiR. Sand backfill, containing Iess than 5 percent lines, may be compacled in loose li(ts not esceeding 12 inchcs when placed bclow 5 Icet of tlic finishcd ground surfacc. [:ach litt must bc compactcd prior to placing Uic subscqucnt ;ill. Prior to compaction, d�c hacklill shuuld bc moisturc conditioned to within 3 perccnt of thc optimum moistw'c content, il necess:�ry. Thc b;ickfill shoidd be cumpacted in accurdance with the criteria discussed above. Pieurc -1 illushutes mcummen�kd �rench compaction eriteria under pavement and nom structur:il areas. Sedimentation and Erosion Confrol In our opinion, ihc crosion potcntial af thc on-sitc soils is low to utodcratc. Construetion xtivitics including gr�ding will esposc suils �o d�c erosiunal efFects of wind and watec TBe amotm[ anJ potential impacts oF crosion are p.i;tly relatcd to tlic time of year that cansvuction actually occurs. Wet �vcathcr constniction will increase tlm amount and extent of crosion�md potential sedimentntion. Iirosion and scdimcntation control mcas:ires may bc implemented by using a combination of intcrceptor swal�s, sir:nv bale barricrs, silt finces and stra�v mulch fur temporary erosiun protecdon of exposed soils. \II disturbed arca;shuuld bc finish gradcd and sccdcd as won ;is praetieablc to rcducc thc risk of crosior,. h:�vsion and sedimenta�ion control mcasure, shuuld bo instulled and maimnined in accordunce with the rcquirentants uf tlic Ci1e ul�G��crctt. EXCAVATIONS � luts �br lhc building ar� anticip;ricd to bc shnllo�v ;�nd cnn likcly bc tnnde as tcmporary opcn cul .lopas dcpcnding on sitc constr.iints. Gxcavalions arc alsu rcquired for undcrground utilitics. Thc stability o'. upcn cut slopcs is a function of soil typc, groimd�eatcr scepaac, slopc indination, slupc hcighl �nd ncurby ,urCace Ioads. Thc usc ol 1118(IL`(�U;l�l'IV (ICSlbill`� O�CII CUlS l'Ol1I[I impact thc stability oF adjaccnt work ircas,cxisting uGlitics,and cndangcr ptrsonncl. hr contractor performing dte work has the primary responsibility far prolection of workmcn and liaccnt improvcmciu�. In our opinion, tho contractor will bc in thc bcst position to obscrvc subsurfacc "nJitions continuously throuoliout Hie construclion process and [o respond to variable ;oil and I �,undwatcr conditiona. 1'hcrcfore, dtc coniractor should Imvc ihc pritnnry responsibility for dcciding u hcthcr or not to use �»en cut slopcs for much of the eecavations rather than sonte form oP tcmpurary cxcav�tiun support, mid for establishing thc safc inelination of thc cut slopc. Acceptable slupe inclir..ations f'or utilities and ancillary excavations should be detemiincd during construction. [3ecause of thc divcrsity of constn�ction tcchiiiyucs and avnilablc shoring systcros, thc dcsign of temporary shonng is most appropri.itelv IcR up to ihe cunu,�ctor prupo;inc to cumplete the inslall�tion. Temporary cut slopes nnd shorin;t �nnst cumplq v:iih thc pru��i;iu,is ut "fitic _")( \V'AC. Part N, "Lxcavation, Trenching and Sliurir.,� " r�i..,:�, c,�r.,-,,�ur �;o ----�� .c�• �� GEoENar+eE�s� r�,,:�,��„�:-.-„�,;