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_ DAVID L.NELSON AND ASSOCIATES,INC. <br /> Consulting Engineering Geology <br /> February 1, 19F5 <br /> '— Project No. 0385 <br /> � Page three <br /> r <br /> I Hydrologic Conditions <br /> .� Ground water was encountered within the site area� in the form of perched <br /> � water, located ,just above the basal dense glacial till , lenerally within <br /> ,,, the more granular gravelly sands. This condition is considered normal where <br /> � more permeable soils overlie �•elatively impermeable basal soils, and the <br /> topographic gradien+ is slight. <br /> � Conclusions <br /> �. Based upon our investigation performed within the site area, we believe the <br /> 1 . proposed additions can be adequately performed within the area provlded that <br /> recortmendations as presented herein are utilized for development and const- <br /> � ruction. ' <br /> ' , Recommendations <br /> G� The surflcial loose, organic ladden and artificial fill soils are not con- <br /> � , sidered suitable for use as foundation bearing soils for shallow spread or <br /> �„ continuous footings. We suggest footings be placed either into the brown <br /> to grey-brown, medium dense gravelly sands or into the basal grey, dense <br /> � glacial tlil. Maximum allowable soil pressures of 2000 pounds per square <br /> foot (psf) are available within the gravelly sands, and 5000 psf is available <br /> within the glacial till for either spread or continuous t,ype footings. The <br /> anticipated dlfferential and total settlement of M�" and 1" is expected. <br /> Footings should be placed into the natural soils which are cleaned of all <br /> �- loosened and saturated soils prior to placement of footing concrete. <br /> Adequate drainage should be provided around the b�iilding areas. We suggest <br /> � the use of foundation and roof drain systems, independantly directed into <br /> the main storm drain system or adequately daylighte� downslope, away from <br /> � the building area. <br /> Slabs-on-grade should be performed upon a prepared base. We suggest the <br /> ` upper 12" of surficial soils be removed from the area and replaced with <br /> at least B" of granular structural fill . The ffll should be placed upon <br /> a prepared subgrade which has been proofrolleG to determine if any soft spots <br />