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

Crow-Western E-270d August 14, 1985 Page 4 to reduce the potential Eor excessive differential settlemenCs the proposed buildiny loads should either be carried down through the fills to coiapetent native soils or alternatively, the buildings shculd be founded on structural fill placed over competent soils. '1'he on-site soils will be difficult to work during and following periods oE sustained precipitation due to tlie high amount of fi�es present. Ideally, grading activities sliould be timed to take place during the dry summer months. Grad::ny activities during the wetter Eal.l, winter and spring months will he subject to delays due to heavy rains. Extra costs for imported clean pit run Eor use as structural fill and the potential for soEtening of previously prapared surEaces due to construction trafEic could be expected durin� construction in wet conditions. The nearly flat site together. with the probable high winter "perched" water tahle will require the establishment of a drainaga system to direct surEace anci near surface water away from construction and/or building areas, The Eollowing sections contain our recoimnendations in greater detail. (�� u Poundations l�% The proposed sl•ructure may be sup�ortad on conventional conti- nuous and spread footings bearing on the undisturbed native till soils or on structural fi11 placed above competent native soils. Fill placed under. Eootings should extend outwards from the edge of the footings at least a dislance equal to the depth of the fill beneath the footings. F'.xterior� footinys should be boltomed at a minimum deptt�� of � welve (12).'inches below the lowest adjacent outside Eini,h yrade. I-nt�rior footinys may be at a depth of twelve (12) inches nelow the top of the slab. Footings founded on competent native till soils and/or on structural Eill may also be designed for a bearing pressure oE two thousand five hundred (2500) pounds per square foot (psf). Continuous and individual spread Eootings si;ould have minimum widths of twelve (12) and eighteen (18) inches, respectively. A one-tt�ir�i increase in the above bearing pressu:es may t�e used when considering shor.t term wind or seismic loads. For the ahove design criteria, it is anticipated that total settlements oE footings f.ounded on native till soils an�9 on fills less than five feet thick will he about three-quarters inch, with diEEerential settlements of one-half inch. Almost all settlements sliould occur during construction. IE any continuous Eootings are located partially in cut and partially in fill, we recommend that the structural engineer consider a�9ding additional teinforcement in the footinqs and fo�tiny walls near the cut-fill transition Earih Consultants, Inc f