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1 1932.003 <br />Lateral pressures from other surcharge and superimposed loads (for example, from <br />vehicle traffic and adjacent structures) should be added to the above recommended <br />lateral earth pressures if the loads fall within a projected area of an imaginary line <br />extended at an angle of 45 degrees from the wall foundation. The surcharge may be <br />modeled as a uniform lateral pressure equal to 33 percent of the surcharge pressure for <br />unrestrained walls and 50 percent of the surcharge pressure for restrained walls. <br />The foundations for walls located within the proposed development (e.9., Lot Nos. '13 <br />and 14) and not along the perimeter of the development may be designed for a <br />maximum, net allowable soil bearing pressure of 2,000 pounds per square foot (psf) <br />provided the footings extend at least 1 foot into suitable beaning soil and are supported <br />at least 18 inches below finish adjacent grade. The minimum foundation width is <br />recommended to be 18 inches. <br />Design of the foundations for the retaining walls along the property lines will require <br />careful evaluation of the soil conditions exposed in footing excavations to verify suitable <br />bearing conditions exist. Due to lhe locations of these walls along the property line, the <br />actual lateral and vertical extent of fill placed during rough grading cannot be verified <br />cannot be established from the available grading report. Therefore, wall construction is <br />anticipated to require increase in footing embedment depth to verify embedment in <br />suitable bearing native soils. However, care must be used to avoid undermining <br />adjacent properties thereby requiring deepened trenches to be excavated in a slolcut <br />manner with the deepened trenches backfilled with a lean cement slurry to planned <br />bearing grade. The individual slots are recommended to be no greater than 6 to 8 feet <br />in length depending upon the actual required depth of excavation. The allowable <br />passive equivalent fluid pressure is recommended to be 200 pcf to a maximum of 2,000 <br />psf. <br />4 € <br />Leighton <br />Foundation Desiqn <br />Based upon the grading operations reported to have been performed and documented <br />during rough activities (Alta, 2017c), suitable bearing structural compacted fill is <br />expected to exist at nominal bearing grade. The minimum depth of structural <br />compacted fill below foundations is recommended to be 3 feet. Based on the reported <br />grading activities, the structural fill requirements are anticipated to exist without the <br />need for additional overexcavation and recompaction, but field conditions should be <br />verified during construction.