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American Property Development ES-0599.06 <br /> June 9, 2016 Page 11 <br /> Revised October 16, 2017 <br /> Foundations <br /> Based on the results of our study, the proposed apartment building can be supported on <br /> conventional spread and continuous footings bearing on competent, undisturbed native soil. <br /> Based on the planned excavations, we anticipate competent native soils suitable for support of <br /> foundations will be exposed at the foundation subgrade elevation. Where loose or unsuitable <br /> soils are exposed at the subgrade elevation, the soil should be overexcavated and replaced <br /> with a suitable crushed rock material. Crushed rock placed below foundations should consist of <br /> one-and-one-half inch to two-inch clean crushed rock. <br /> Assuming the foundations are supported on competent, undisturbed native soils or suitable <br /> crushed rock material, the following parameters should be used for foundation design: <br /> • Allowable Soil Bearing Capacity 10,000 psf <br /> • Friction 0.40 <br /> • Passive Resistance 350 pcf (equivalent fluid)* <br /> *Assumes foundations backfilled with structural fill <br /> For short term wind and seismic loading, a one-third increase in the allowable soil bearing <br /> capacity can be assumed. A factor-of-safety of 1.5 has been applied to the friction and passive <br /> resistance values. <br /> With structural loading as expected, total settlement in the range of one inch is anticipated, with <br /> differential settlement of about one-half inch or less over the span of a typical column spacing. <br /> The majority of the settlements should occur during construction, as dead loads are applied. <br /> Slab-On-Grade Floors <br /> Slab-on-grade floors for the proposed building structure should be supported on competent <br /> native soil or a compacted structural fill subgrade, as appropriate. Unstable or yielding areas of <br /> the subgrade should be recompacted or overexcavated and replaced with suitable structural fill <br /> prior to construction of the slab. A capillary break consisting of a minimum of four inches of free <br /> draining crushed rock or gravel should be placed below the slab. The free draining material <br /> should have a fines content of five percent or less (percent passing the #200 sieve, based on <br /> the minus three-quarter-inch fraction). In areas where slab moisture is undesirable, installation <br /> of a vapor barrier below the slab should be considered. <br /> Earth Solutions NW,LLC <br />