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Lutzky Associates Development. LP - Geolechnical Investigation <br />MACTEC Project 4953-03-263] <br />September 18.2003 <br />As the on-site upper clayey soils are moderately expansive, at least 2 feet of compacted fill <br />consists of non-expansive soil should underlie any floor slabs or other concrete slabs-on-grade. <br />We understand that the lower floor will be structurally supported due to the base isolation system. <br />If there are any floors to be supported on grade, there is a risk of damage due to the estimated <br />liquefaction-induced settlements Of up to !/2 to % inch. If this risk is not acceptable, these ftoor <br />slab should be structurally supported. <br />We recommend that the proposed Data Center bd supported on pile foundatiof*9nsidering th'e <br />soils beneath the site an*J»expected•colamn:18*s. However, if the anticipated static settlements <br />and liquefaction-induced settlements can be accommodated, the proposed Data Center may be <br />supported on shallow spread type foundations. The anticipated static settlements could be <br />minimized by surcharging the entire footprint of the project area as described in Section 6.11, <br />Grading. Conventional spread footings may be established either in undisturbed natural soils or on <br />properly compacted fill soil. <br />Because the on-site clayey soils are expansive, mitigation measures discussed in Section 6.11, <br />Grading, will be required to prevent heaving of floor slabs and other concrete slabs-on-grade. <br />Existing parking lots at the project site should be cleared before starting construction. <br />Based on corrosion tests, we recommend that Type V cement, a maximum water/cement ratio of <br />0.45, and minimum strength of 4,500 psi should be used for concrete structures and pipes td <br />protect against sulfate attack. <br />6.2 DRIVEN PRE-CAST CONCRETE PILES <br />Axial Pile Capacities <br />The downward and upward capacities of 12- and 14-inch-square driven concrete piles for <br />supporting the proposed Data Center are presented on Figure 6, Axial Driven Pile Capacity. Dead <br />plus live load capacities are shown; a one-third increase may be used when considering wind or <br />seismic loads. The capacities are based on the strength of the Soils; the compressive and tensile <br />strength of the pile section itself should be checked to verify the structural capacity of the piles. <br />16