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

Proposed ReL:il Development J-I443 112�'Street and Hwy.99 February 26,2004 � Everett,Washington Page 3 outside the building and any appurtenances. P/here peat is left ir place, long-term consolidation of the peat should bc expected. T'he owner s6ould consid�. the risk of lea-�ing the peat in place outside the building pad. . During wet weather condi6ons, earthwork will becnme more difScult at th� site due to the moisture-sensitive nahue of the glacial till soils. Soils wet of eptimum will require acration and drying or possibly admixhue treatment with a pmduct such as keln dust or cement in order to achieve the minimunt compaction levels. Native,silry soils subjected to construction traffic should be covered wilh a minimum of 12 inches of clean pit-run sand and gravel or other suitable select material to protcct the sensitive subgrade under such conditions. . Excavations for utilities or other underground structures are not expected to encounter a regiona] groundwater tablc. However, perched groundwater may be ei�countcred above the glacial till contact. . The cxisting concrete pipc that routes Swamp Crcek under the sice should be completely removed and the resulting excavation backfilled with suuctural fill. We also recommend that a ditch plug be installed in the end of the trench excavation nearest to the new stream alignment. T6is would prevent seepage from entering the structurnl backfill and migrating under the proposed building. , • Petroleum-impacted soils may be encountered during the earthwork-related phases of the ' project. As noted in the October 2002 Limited Phase II Environmental Site Asscssment report prepazcd by ZZA, petrolcum concentrations encountered to date are below cleanup levels. However, if impacted soils are encountered, we recommend that repmsentative samples be tested to dct�:rmine if it is possible to leavc the soils on site. Structural Fill • All fill used to raise g�ades should be compacted to a minimum 95 percent of the modified Proctor maximum dry dcnsity within f2 percent of the optimum moisture content. • Most soils encountered on site are considered suitable for reusc as structural fill. However, during construction, it will become apparent that some soils will not be suitable for teuse as shvctural fill due to the level of delcterious materiais in the soil. • Depending on the soil moisture content at the time of construction, some of the near-surface soils may require moisture reduction to allow for reuse as structural fiIL Buiiding Foundations • Foundations may consist of continuous perimeter and isolated, interior column footings. • Foundallons supported on compacted structural fill or medium dense to dense naUve soils may be designed for a maxunum allowable, net, bearing capacity of 2,000 psf. All foundation i J-1443,022604 ' 3 `;