2522 RUCKER AVE 2018-01-01 MF Import

I Geotechnical Engincering Report • Gardener Group Condominiums July l6, 1997 ( NCA File No.209297 I Page 5 ISubsurface The explorations encountered a surficiel layer of topsoi� or fill up to 2 feet in thickness consisting of I brown to gray, loose,si�ty fine sand with gravel and trace roots. Underlying the su�cial soil,a layer of medium dense, rust brown silty fine sand with gravd was encountered. This unit is interpreted to be weathered till. Underlying the weathered till, dense to very dense gray s��ty fine sand witM gravel and Icrace fine sand seams was encountercd. This is interpreted to M glaciel till. The dense till soils were Iencountered at depths of 4 to 8 feet below the surface to the full depths explored. I Hydrologic CondiNons Ground water or seepage was not encountered in our borings. However, it is not uncortirt�on for ground water in the su�cial soils to be parched on the till,or lacally within sand seams. We could expect some Iwater to exist in the upper weathered zones during the wetter porlions of the year• I SENSITIVE AREA EVALiJATION Sei�mic Hazard I The Puget Suund region is classified as a Zone 3 by the Ur.ifortn Building Code. Geologic haz.acds associated with seismicity include liquefaction, ground movement amp��fication. Liquefaction is caused I yy a rise 9n pore pressuros in a loose sand deposit. The till is not considered susceptible to liquefaction. It is our opinion that there is not significant potentiel for high amplification of ground motion. I CONCLUSIONS AND RECOMMENDATIONS General I The site is suitable for the plenncd development from a geotechnical viewpoint. The underlying till will provide good foundation support of the shucturc. We encountered minor amounts of fill at the site. We I anticipate that greater amounts of fill will be encounterod closer to the retaining wall as tetaining wall backfill,but this fill will be rerooved during excavation of the building,based on cutrent elevations. We recommend that the foundations extend through any fill,or loose disturbed soils,and bear on the medium ( dense to very dense glacial till,or structural fill extending to these soils. � Excavation geometry between the adjacent off-site structures and the project site will be a significant I conccrn. The excavation depth is up to 15 feet et:a as much as 8 feet below foundation elevation of I adjacent structuros. Our field measurements indicate thet temporary ou�s from the base of the existing foundation for the adjacent swcmres to ihe bottom of the proposed footings would exceed a 1 f Horizontal to 1 Vertical (1H:1V) inclination. It is likely that cut slopes would cross the property lines I NELSON-COUVRETTE &ASSOGATES, ING �