6101 ASSOCIATED BLVD BASE FILE 2017-06-05

Underwood Gartland Everett, LLC ES-2232.02 February 6, 2015 Page 5 • Excavations and related compaction and preparation of the subgrade for support of the building foundations. • Final grading of the building pad areas and preparation of the subgrade for the building slab-on-grade. • Underground utility installations and related backfilling and compaction. • Excavation and related construction for the stormwater pond facilities. • Final site grading and preparation of pavement subgrade areas. Existing Building Pad Fill The existing building pad fill material is comprised primarily of silty sand soils. This material is moisture sensitive, and will become unstable and difficult to compact in a wet to saturated condition. In this respect, moisture conditioning of the existing fill (particularly the upper two feet) may be necessary if intended for use as structural fill below foundations and throughout the new building footprint areas. The geotechnical engineer should evaluate the suitability of the existing fill soils for use as structural fill during construction. If determined necessary, soil amendment or overexcavation and replacement with a suitable structural fill material may be recommended. Imported Soil Imported soil required for use onsite as structural fill should consist of a well graded granular soil with a moisture content that is at or near the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well graded granular soil with a fines content of 5.0 percent or less defined as the percent passing the #200 sieve, based on the minus three-quarter inch fraction. The geotechnical engineer should be provided samples of proposed imported soil for assessment of suitability. Temporary Erosion Control Temporary construction entrances and drive lanes, consisting of at least 12 inches of quarry spalls can be considered in order to minimize off-site soil tracking and to provide a stable access entrance surface, as necessary. Erosion control measures should consist of silt fencing placed along the perimeter of the construction site, as appropriate. Where necessary, soil stockpiles should be protected to reduce soil erosion. The geotechnical engineer should review the site erosion control plan prior to earthwork activities, and provide supplement recommendations for erosion control, if necessary. Structural Fill Structural fill for the proposed development is defined as compacted soil placed in foundation, building pad, slab-on-grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas are also considered structural fill. Soils placed in structural areas should be placed in maximum 12 inch lifts and compacted to a relative compaction of 90 percent, based on the maximum dry density as determined by the Modified Proctor Method (ASTM D-1557). In slab-on-grade and pavement areas, the upper 12 inches of the structural fill should be compacted to a relative compaction of at least 95 percent. Earth Solutions NW, LLC