5720 EAST DR 2018-01-02 MF Import

Geotechnical Engineering Report Parcel 00471700002401- 57XX East Drive Everett, Washington December 12, 2009 RMI File No. 53409 Page 7 representative number of in -place density tests to document the attainment of the desired degree of relative compaction. The areas to receive fill should be prepared as outlined in the Site Preparation and Grading subsection of this report. Materials: Imported structural fill should consist of a good quality, free -draining granular soil, free of organics and other deleterious material, and be well graded to a maximum size of about 3 inches. Imported, all-weather fill should meet these requirements, and also should contain no more than about 5 percent fines (soil passing a U.S. No. 200 Sieve), based on that fraction passing the U.S. 3/4-inch sieve. The on -site native soils predominantly comprise medium sand with some silt. It may be feasible to use this material as structural fill, if it is relatively free of organics and can be moisture -conditioned to near - optimum moisture content for compaction. The necessary moisture -conditioning may consist of drying the material, which would require an adequate area to spread the material out. Drying the material may not be possible outside of the summer season. Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. All fill should be placed in 6- to 8-inch thick uniform lifts, and each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas should be compacted to at least 95 percent of its maximum dry density. Maximum dry density, in this report, refers to that density as determined by the ASTM D 1557 compaction test procedure. The moisture content of the soils to be compacted should be within about 2 percent of optimum, so that a readily compactable condition exists. It may be necessary to overexcavate and remove wet soils in cases where drying to a compactable condition is not feasible. All compaction should be accomplished by equipment of a type and size sufficient to attain the desired degree of compaction. Foundations Conventional shallow spread foundations should be placed on undisturbed medium dense or better native soils. Where less than medium dense soils are encountered at footing bearing elevation, the subgrade should be overexcavated to expose suitable bearing soil. The overexcavation could be filled with structural fill (see subsection on Structural Fill) or the footing may be extended down to the bearing RMI ASSOCIATES LLC &