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2401 Taylor Drive Geotechnical Engineering Study <br /> Everett,Washington <br /> The area bounded by lines extending downward at 1H:1V(Horizontal:Vertical) from any footing <br /> must not intersect another footing or intersect a filled area that has not been compacted to at <br /> least 95 percent of ASTM:D 1557. In addition,a 1.5H:1V line extending down from any footing <br /> must not daylight because sloughing or raveling may eventually undermine the footing. Thus, <br /> footings should not be placed near the edges of steps or cuts in the bearing soils. <br /> All footing areas should be observed by SGP prior to placing concrete to verify that the exposed <br /> soils can support the design foundation bearing capacity and that construction conforms with <br /> the recommendations.in this report. Foundation bearing verification may also be required by the <br /> governing municipality. <br /> Structural Fill <br /> Structural fill may be necessary to establish desired grades. All references to structural fill in this <br /> report refer to subgrade preparation, fill type, placement, and compaction of materials as <br /> discussed in this section. If a percentage of compaction is specified under another section of this <br /> report,the value given in that,section should be used. <br /> After stripping, planned excavation, and any required over-excavation have been performed to <br /> the satisfaction of the geotechnical engineer/engineering geologist, the upper 12 inches of <br /> exposed ground should be recompacted to a firm and unyielding condition. If the subgrade <br /> contains too much moisture,adequate recompaction may difficult or impossible to obtain and <br /> should probably not be attempted. In lieu of recompaction, the area to receive fill should be <br /> blanketed with washed rock or quarry spells to act as a capillary break between the new fill and <br /> the wet subgrade. -Where•the exposed ground remains soft and further..ouer-.excavation is <br /> impractical, placement of an engineering stabilization fabric may be necessary to prevent <br /> contamination of the free-draining layer by silt migration from below. <br /> After recompaction of the exposed ground is approved, or a free-draining rock course is laid, <br /> structural fill may be placed to attain desired grades. Structural fill is defined as crushed rock, <br /> acceptable to the geotechnical engineer,placed in maximum 8-inch loose lifts with each lift being <br /> compacted to 95 percent of ASTM:D-1557. In the case of roadway and utility trench filling,the <br /> backfill should be placed and compacted in accordance with local codes and standards. The top <br /> of the compacted fill should extend horizontally outward a minimum distance of 3 feet beyond <br /> the location of the perimeter footings or roadway edges before sloping down at a maximum angle <br /> of 2H:1V. <br /> The contractor should note that any proposed fill soils must be evaluated by SGP prior to their <br /> use in fills.—This would require thatwe-have a sample of the material at least 72 hours in advance <br /> to perform a Proctor test and determine its field compaction standard. Soils in which the amount <br /> of fine-grained material (smaller than the No.200 sieve)is greater than approximately 5 percent <br /> (measured on the minus No.4 sieve size)should be considered moisture-sensitive. Use of <br /> November 6,2019 SONDERGARRD GEOSCIENCES,PLLC <br /> 8 <br />