10200 19TH AVE SE Geotech Report 2018-01-02 MF Import

' i CONCLUSIONS AND RECGMMENDATIONS GENERAL We conclude that the proposed Costco Wholesale wazehouse can be satisfactorily supported � on conventional shallow foundations. Floor slabs can be suppocted at-grade. Propec site t' ' prepazation and earthwork procedures will be impoctant beceuse the giacial till soils are vay � moisture sensitive and substantial cuts and filis aze aniicipated for the project. These soils aze � particulazly sensitive tn disturbance froru conswctian equipment during wet weather. Compaaion and proofrolling of the subgrade must, therefore, be carefully monitored so that the site soils aze not unduly disturbed. Should softening or cutting begin to oc.^ur duriog subgrade �' ' � prepararion, we recommend that the equipment be remuved from the area and an access road anc! • layout areas be cons[ructed using quarry spalls or ciean gravel. 'Ihe dll does not allow rapid drainage of surface water. It is :�so difficult or impossible to compact during wet weather or when the moisture content is nver the optimum. 'Il�erefore, to minimiu gading costs and use the on-site material for structural fill, grading should be planns�during the dry summer months. Our re�,rommendations �re presented in the following subseexions for site prepazatloa an�i earthwork to develop satisfactory savctural support and to reduce postconsavctior.settlemenu to acceptable limits. Specifically, we present recommendations for: . _ • Site prepazation k+' . • Fill slopes ' • Structural fill ;, • Foundacion suppurt ' + Fioor slab suppoit ' -' • Lateral resistance k. • Retaining walls • Pavements • Drainage considerations • Seismic considerations SITE PREPARATION P.11 on-site structures should be demolished and removeci from the site. We recommend that, where practical, all existing foundations be removed to reduce pmblems durin6 consavction ' . of utilities and other below-grade structures. In pazking azeas where utility in!erfuence is nut a concem, subsurface foundation elements should be removed to at leazt 2 feet below finished 4" grade and fill placed to subgrade. 1'he residential stmctuces may contain asbestos. We } recommend thet an ACBM (asbesros containing building material)survey and sampling program be periorme� prior ro the demolishing the buiidings. 7'he survey shrntld indude destructive sampling to assess the presence of asbestos in building materials located within azeas that aze accessible and azeas that aze accessible by modifying ur demolishing interior and eacterior building G e a E n g i n e e r a 4 Rle No.0975-017-R73/062993