11310 EVERGREEN WAY 2018-01-01 MF Import

Mr. Bruce Vanderwall _ ... April 16, 2008 ' , • If greding acdvides must take place during wet weather or on a wet subgrade, the � , contrador wfll need to take care that the soils do not get too wet during grading. The glacial dll nathre soils and the silty existing fllis around the pad are very moisture sensitive and difficult to use in wet weather. In tfie dry summer months, tt�ese materials may requlre water during grading and canpaction. Any needed additional � import fills should be predominantly grenular with a maximum s(ze of three inches and • no more than five percent fines passing the No. 200 sieve. Tempordry cuts made (n the filis and nadve weathered soils above the UII can be made at a 1:1 (H:V) inclinatlon. Temporary cuts in the dense till pn be made vertically in the lower 4 feet, then sloped up at a 0.5:1 (H:V) Incllnatlon for deep cuts such as a r�ew detention vault These temporary cut conFlgurdtions can-also be used elsewhere on the � site for utility trenching. The contractor should utllize appropriate local and sqte � standards for excavation work to maintain a safe work ernironment. � Prior to use, ABPB Consuldng should examine on-site or imported maferials proposed for use as structural fili. Alternatively, reilroad bailast or small quarry spalls may be used over wet subgrades as structural fill material. Any structural fill used for the project should be placed in uniform loose layers not exceeding 12 inches and then compacted to a minimum of 95 percent of the soil's maximum dry density as determined by A.STM Test Designation D-698 (Standard Proctor). The moisture content of the soil at the tlme of compadion should be within two percent of its optlmum, as determined by this ASTM standard. In non-structurel areas or for backfill in utility trenches below a depth of four feet, the degree. of compaction could be reduced to 90 percent. Foun ations �ollowing the demolition and removal of the existing buildings, slabs and foodngs, new foundations may be supported on conventional spread footings bearing on competent dense native soils cr on structural fill placed in overexcavated areas of old fill. In areas of old fills, foundation areas (both contlnuous and individual) should be overexcavated to extend down to competent native sofls. We anticipate the over- excavations will slope from a low point at the southwest building corner up to the north and east. Structural fiil can then be placed in layers within the over-excavations and be compacted as noted above in the Site Preparation section. Alternadvely, the fill can consist of clean railroad ballast rock or CDF (Controlled Densiry Fiil — lean concrete) if desired. We sugg�st that the trenching be conducted prior to raising the whole building pad up with additional fill to the fina! subgrade leveis. Project No. 12 Page No 6�/�