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Campbell-Fleury Investments/Mallwest Center <br />9 April 1986 <br />W-3103-1 <br />Page 7 <br />_ 4.3 Shallow Foundations <br />The structures may be supported by conventional shallow spread footings, continuous <br />wall footings, or extended footings. If the structure is to be founded on structural <br />fill after total removal of the fill and relic topsoil, conventional spread footings <br />and/or continuous wall footing, may be used. Al1 existing uncontrolled fill and <br />organic native soiis beneath any footings should be removed and replaced with <br />structural fill. The extent of structural fill beneath any footing should begin <br />- at least 1 foot frum the edge of the footing and slope downward and outward from <br />the footing at an angle no steeper than 1H:1V (Horizontal:Vertical) to suitable <br />_ undisturbed natural bearing soils. This would result in a compacted wedge of <br />structural fill beneath the footing and on which stresses of the footing wi11 be <br />carried, <br />If uncontrolled fill soi',s are to remain, the structure should be directly founded <br />on suitable undisturbed, natural bearing soils utilizing extended spread footings <br />to bring the foundation up to grade. <br />All footings should have a minimum width of at least 12 inches. The base of the <br />exterior footing should be located at least 18 inches below the lowest adjacent <br />ground surface or top of floor slab, whichever is lower. The interior footings <br />need only extend 12 inches below the lowest surrounding grade or slab surface. For <br />foundation elements founded on native soils or structural fill, we recommend that <br />the footings be designed with a maximum allowable bearing pressure of 2500 pounds <br />per square foot (psf). This allowable bearing pressure may be increased by up to <br />one-third to accommodate seismic or transient loads. All footings must penetrate <br />into the prescribed bearing stratum and the foundatior should not be set in or above <br />loose or disturbed soils, organic soils, or any existiny fill. <br />�-. Assuming that foundation elements are founded on the prescribed bearing stratum, <br />we anticipate that total settlements should be less than 1 inch with differential <br />,� settlements on the order of one-half of tnat total. However, if disturbed or soft <br />materials are left in the footing area prior to concrete placement, the settlements <br />� <br />