4805 BELVEDERE AVE 2016-01-01 MF Import

Su6surface Fxploration, Geolvgic Nacnrd, and liclvedcre Lntr East Preliminary Geerechnical Engineering Repon Fi erert Washinemn Prelimimry Design Recommendatio�u during warm, dry weather, or incorporating an admixture into the soil such as fly ash or kiln dust. The on-site eilt sediments are not considered suitable for use as swctural fill. In the case of roadway and utiliry trench backfill, the structural fill should be placed and compacted in accordance with current local or counry codes and sandards. The top of all compac�ed fili should extend horizontally outward a minimum distance of 3 feet beyond the location of perimeter footings o• pavement edges before sloping down at a maximum angle of 2H:1V. Structural fill placed in foundation cxcavations must extend horizontally outward from the edges of the footings a distance greater than or equal to the thickness of the fill below thc footings. The contractor should note that anV proposed fill soils must be evaluated by Associated Earth Sciences, Inc. (AESI) prior to their use in fills. 7'his would requirc that we have a sample of the material at least 3 business days in advance to perform a Proctor test and dctermine its field compaction standard. Soils in which the amount of fine-grained macerial (smaller than the No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Use of moismre-sensitive soils in structural fills should be limited to favorabl� dry weather conditions. In ad�ition, conswction equipment va�:ersing the site when the soils are wet can cause considerable dismrbance. If fill is placed d�ring ��et weather, or if proper compaction cannot be obtained, a select on-site and/or import ma:erial consisting of a clean, fYee-draining gravel and/or sand should be used. Free-draining fill consists of non-organic soil with ihe amount of fine-Frained material limited to 5 percent by weiglu when measured on the minus No. 4 sieve fraction and at least 25 percent greater than the No. 4 sieve. A reptesentative from our firm should observe the stripped subgrade and be present during placement of strucr�ral fill to ohservr the ti•ork and perforrn a representative number uf in- place density tests. In this way, the adequac}' of the earth��nrk may be eealuated as filling progresses xnd an� prohlem arcas ma}� hc corrected at that time. It is importan? to understand that taking random compaction tests �:i a part-time basis will not assurc uniformiry or acceptahle rerformance of a fill. As such, we are available to aid the owner in developing a suitablr monitoring and te�.ting frequcncy. I LO '.�OUNDA'I'IONS The �isk o( dama�z to the prnposed structures hy seismically induced landsliding is low, pro��ided the recommendations contained in this report are properly follow�ed. Our analyses indicate loa factors of safet}' under seismic conditions (or theore[ical landslide failure surfaces N�uhin d0 (ret of the top of the stetp slope. Using the Newmark method, our analyses have also indicated that die calculated downslope movement associated with landsliding under the design seismic conditions is relatively small (approximately 0.5 inch or less) at distances of 20 feet or more behind thc �op of the slope. In order ro mitigare landslide hazards associated with ,Vurth 5, �(X)�t ��-- AS30ClAltU t.�n%ri SCic'n'Cc'S, iN�. ,. ..: �� „�� ,,,,,,,��r ��ti�„��,�.r k�� ;�:� Page 12