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Grifin Really SA, Inc.-Geolechnical Investigation <br />Law/Crandall Project 70131-7-0261.0001 <br />July 8. 1997 <br />A coefficient of friction of 0.4 can be used between the fioor slab and the supporting soils. The <br />passive resistance of natural soils or properly compacted fill soils can be assumed to be equal to <br />the pressure developed by a fluid with a density of 300 pounds per cubic foot. A one-third increase <br />in the passive value can be used for wind or seismic loads. The frictional resistance and the <br />passive resistance of the soils can be combined without reduction in determining the total lateral <br />resistance. <br />Installation <br />All drilled pile excavations should be observed by personnel of our firm. Because of the sandy <br />soils, minor difficulties should be anticipated in drilling the pile shafts because of caving. Water <br />was encountered at depths of 65'/1 and 67'/1 feet below grade. Accordingly, pile tip evaluations will <br />be established above the water level. Also, due to the sandy layers, localized water seepage zones <br />may occur above the groundwater levels encountered in our exploration borings. <br />Depending on the typeof drilling equipment used by the contractor, some caving and raveling will <br />occur within the pile shafts during drilling. Precautions should be taken during the installation of <br />the piles to reduce caving and raveling. Among other precautions, the drilling speed should be <br />reduced as necessary to minimize vibration and sioughing of the sand deposits. <br />Closely spaced piles should be drilled and filled alternately, with the concrete permitted to set at <br />least eight hours before drilling an adjacent hole. Pile excavations should be filled with concrete as <br />soon after drilling and inspection as possible; the holes should not be left open overnight. The <br />concrete should be placed with special equipment so that the concrete is not allowed to fall freely <br />more than 5 feet and to prevent concrete from striking the walls of the excavations. <br />Spread Footings for Minor Structures <br />Spread footings, for minor structures, established in the undisturbed natural soils andjor properly <br />compacted fill soils may be designed to impose a net dead plus live load pressure of 2,000 pounds <br />per square foot. A one-third increase in the quoted bearing value may be used when considering <br />6