1111 CRAFTSMAN WAY 2016-01-01 MF Import

� BSURFACE CONDITIONS I SU Soil Conditrons SuUsurface conditions were evaluated by drilling two borings and advancing five CPT proUes. 1'he borings were drilled with a subcontracted mud-rotary wok-mounted drill rig and the CPTs ��ere also completed with a subcontracted truck rig. The approxi:natc locations of thc esplorations are shown on thc attachcd Site Plan, rigure 2. Dctailed logs oCthe explorations are pro��ided in the appendix. Subsurf'ace soils encounrered at the sitc consist of loose grading to vcry loose/very soft fill and fine-grained sedimcnts to a depth of 2G to 30 feet. The fill consists of silty fine sand and highly compressible silt. Beneath the fill and so(t sedimcnts we encountcrcd mcdium densc to very dense silty sand Qikely glacial till) and hard silt (�Vhidbcy fommtion). The hard silt was typically cncountered at a depth of�2 to�3 feet below the ground surface. Groundwater Conditions Groundwat�r was encountered at a depth of 8 to 12 fect below the ground surface during drilling. 7'hc I ground�vater should be cxpcctcd to fluctuate with changes in thc adjaccnt tidcs, season, and precipitation. CONCLUSIONS AND RECOMMENDATIONS GENERAL Subsur(ace soils at the site consist oCioosc silty sand fill and highly comp:essible silt. Placemcnt of fill and building loads may result in consolidation of the soft silt and resulting ground settlement. This ��ill uccur in areas that have not experienced similar areal loading in ihe past. The proposed building can be supported on shallow spread footings bearing on a zone of compactcd structural fill providcd thc cstimatcd ground settlements are tolerable. I We undcrstand that the finished tloor clevation �vill be near Glevation IS fecL Based on the exis[ing :md proposed sitc grades, it appears that minor grading will be necessary to conswct the sub�Rade Cor thc � building and surrounding f�cility. Cxcavation and replacement of the on-sire soils �eill bc necessary to � provide the recommended capillsry brcak layer and structural fill zone bcncath footings. In addition, somc c�cavation and placement of 2ill to provide suitable subgrade for die pavement should also be anticipated. Recommendations for minimum subbase thicknesses and strucmral fill placement are pro��ided in detail in follo��ing sections. A summary of the primaq� site preparatian, design and construction considerations for the proposed project is providcd Uelow. The summary is presented Cor introductory purposes only and � should be used in conjunction with die complete recommcndations presented in this report. • Surficial soils at the site consist of both loosc silty sand fill, and areas of crushed rock. The silty sand fill soils are extrcmcly moisturc-scnsi[ive and �vill not be accessible during �vet ��eathcr. It may be i�ecessary to provide additional crushed rock to pro��ide a working surface and site access ' if construction occurs during the wct season. • The exposed subgrade should be compacted to a minimum of 95 percent of the maximum dq� dcnsity (MDD) in accordance with ASTM D-1>j7 prior to placing the recommended subbase discussed bclow. IC thc exposed subgradc is too �vet and can no[ be properly conditioned, excavation and replacement with import fill will be necessary. • Nc recommend a minimum 6-inch-thick subbase underlie slabs-on-grade to provide uniform support and a capillary break. The subbase should consist of clean 3/4-inch minus crushed rock Filr No. I?65?-00I-00 PubB� GEOENGINEENS� � A'ovrmGer 6,?OOh