11632 EVERGREEN WAY BASE FILE 2018-01-01 MF Import

Proposed Retail Development J-t443 112'�Street and Hwy.99 February 26,2004 /" Evcrett,Washington Page 4 \ subgrades and structural fill placed beneath foundation elements should be compacted to a minimum of 95 percent of the medified Proctor Maximum dry density(ASTM D-1557). Buildiag Floor Slab • The floor slab will likely be supported on a combiaation of cuts and fills. In the transition behvecn the cut and fill azeas, loosc native soiis may be present. Loose soils exposed aftet stripping would not be suitable for floor slah support unless compacted. The upper 12 inches of exposed loose soil should be compacted to a minimum of 95 percent of thc modified Proctor maximum dry density. In fill areas, all undocumented fill should be overoxcavated and replaced with compacted structural fill prior to placing the remainder of the fill to achieve grade. Whcre peat is present bclow fill materials, the peat should also be overexcavated and replaced. On-site soil reused for structural fill s:iould be moisture conditioncd aa necessary and recompacted to a minimum of 95 percent of the modified Proctor maximum dry density. Achieving 95 percent compaction in the upper l2 inches would provide a slab subgrade modulus of 200 psi/in. • For expased concrete tloors,we recommend that the slabs be underlain by a 8-inch Uuck layer consisting of 2 inches of Sne aggregute base o��er 6 inches of warse aggregate base. T'he 6 inches of coarse aggregate will also serve as a capillary break. • If wet weather construction is anticipated, we recotnmend tLat those poriions of the building pad, construction haul roads, and lay-down azeas that are underlain by glacial rill be pmtected with a minimum 12-inch thick layer of clean pit-mn or select granulaz fill in order to protect the moisturc-sensitive soils and reduce the magnitude of disturbance to the underlying subgradc • Provided the slab is undcrlain by granular soils, it is our opinion that a vapor barrier is not necessary. Drainage • A perimetcr footing drain system is recommended around the building and behind all retaining walls dur to the presence of relatively impermcable glacial till soils across Ihe project site. Retaining Walls • Backfilled subsurface walls should be designed using equivalent fluid pressures cf 35 and 55 pcf for active and at-rest loading conditions,respectively. • Walls shouid be backfilled with a minimum of 18 inches of free-draining granulaz structural fill that provides drainage to a perforated fooring drain and/or weepholes at the base of the walL J-1443,022604 . N ;