11611 AIRPORT RD Geotech Report 2018-01-02 MF Import

l � Geolechnical Gngineering keport Pruposed Ahn Warchouse May I 1, 2001 CG File No. l 12l Page 5 CONCLUSIONS AND RECONiMENDATIONS General We recommend that the footings for ti�e building extend through the existing fill and be founded on the underlying medium dense .� ue[ter, native soils or structural fill extending to these native bcanng soils. "1'he new building is planned to consist of daylight basement construction, which may extend through [he fill. If the nonstructural fill exists at the planned footing elevation, additional overexcavation should occur. The shucture can be supported on the native soils by u�ing deepened footings, or hy overexcavating the existing loose, uncontrolled fill, and replacing the fill with compacted structural fill,or by using Controlled Density Fill (CDF)trenches. S[ructures or hard surfaces, such as conerete or pavement supported on the uncontrolled fill, can be expec[ed to set[]e. The amount of settlement will vary depending upon the quality of fill and leve� of compaction when placed. Areas with a higher organic content, such as topsoil or logs can be expected to settle more, as the organics decay. This can result in low spots, or bird baths, in the pavemenL The best me[hod is to overexcavate all of the fill .o expose native, medium dense, or better soils, and then place structural fill to planued ?ievations. However, this can be cost prohibitive. Therefore, we recommend t�at the uppe; 2 feet of fill be removed and replaced with structural fill. 'lhis wtll have an increased s�sk of settlement than if all of lhe fill was overexcavated,but will perform better than if all of the fill was left as is. The soils likeiy to be exposed dunng construction are highly moisture sensitive and will disturb easily when wet or during wet conditions. �Ve recommend that construction take place during the drie� summer months, if possible. If construction takes place during the wet season, additional expenses and delays should be expected due to the wet conditions. Additional expenses could include the export of on-site soil, the import of clean granular soil for fill, anr�the need to place a blanket of rock spalls in [he access roads and paved areas pnor ro placing strucmral fill. Site Preparations and Grading The first step of site preparation should be to stnp the vegetation, topsoil, existing [ill, or loose soils to expose medium dense to very dense, native soils in the footing areas. Areas to receive pavement or slab-on-grade should have the upper 2 feet of existing fill removed. This material /A�� Cornerstone Geotechnical, Inc. Y�