1510 SE EVERETT MALL WAY Geotech Report 2018-01-02 MF Import

' September 30, 2009 ProjcctNo. T-G366 building foundalions. Trenches from rentoved lines should be backfilled .structurally as described below, Abandoned utilities thal v�e outside ihe limits of Qie ncw Uuilding construction can be lefl in place, �providcd they are sealed to prevent in�rusion of groundwater seepage and soils. Grad•,ng to estnblisl� building Ooor and foundation �rades sliould be o�served by a represcntativc of Terrn Associales, lac. to verify tliat soil conditions exposed are as expected.and suitablc for support of building elemeu�s or new fill material. This is especially impanan; in the vicinity of test boring B-3 where fill maierial associated witL backfilling of a previous UST cavity is indicate�. The test boring indicates tUa't tl�e fill is well compacled and suita6le for suppon of spicad fooling foundations designed as recommended in tl�e following foundation section of tliis report. This fill condition sli�uld ee verificd by obscrvation and additional testing when tlie subgraAe in tliis area is expased. 1'hc cxisting granulaP t�ll is rclativcly frce of soil fines and should be suitable for re-usc as slrucwral fill durin6 most �vcaqicr corditions. TI�e native glacial till soils contain a significant amounF of soil fines (silt'and clay size particles), Thesc soils will bc difficult to compact as structural fll when too wct or too dry.. Aceordingly, thc ability to use native glacial soils from sitc cxcnvalions us strucmral fill �vill depend on their moislure contcnt and Ilie prev�iling weather co��ditions at ti�e time site gr�ding activities take place. The conlractor sliould be prepared io moislure condition soils ns necded. . If grnding activities are planncci during Qie tvet winlcr monlhs, or if Ihcy arc ini�iated during the.summer and cxtcnd into tall and winter, the owner'should bc prepnred lo import wet wealher structural fill; Por this puiposc, we rccommend importing a granular soil wliich meels lhe following gradiug requirenienis: *Bascdbn the 3/4-inch fraction. Pnor lo usc, 7erra Associ�tcs, Inc, sltould examinc and test all mnterials importcd to lhe site for use as suvctural fill. 1Vc recommcnd lhat struclural fill Ue placcd in uitifon» ]oose layers not exceeding 12 inches in thickness and compacicd to a minimum of 95 percent of the soil's ntaximum diy densiry as determined'by Americnn Sociery for Tcsling and Malcri�ls (ASTM) .Test Designuia� D-1557 (Modificd Proctor): Tlie moisture contenf of thc soil at thc time oT compaclion should bc within hvo percenr of its optimum, as de�ennined Uy this same standard. Li nonstn�clural arcas, the degree of compaction may be reduced to S5 percent. 4.3 Fomidntions Tlie building may bc suppoiled on conventioiial spread footing foundations Uearing on competent native soils or existing canpact fills observed belo�v ihe ezisting asphall surfacing. All foundation Uearing surfaces should bc Page No. 4 / �