2106 GRAND AVE 2016-01-01 MF Import

' GEOTECHINCAI HJGINEERING STUDY E-12863 � Narch 17,2007 ' Horizontal loads can be resisted by friction between the base of tlie foundation and the supporting soil and by passive soil pressure acting on the face of the buried portion of the foundation. For frictional capacity, a coefficient of 0.35 should be used. Resistance due to � passive earth pressure may be computed using an equivalent fluid pressure of 300 pounds per cubic foot (pc� for footings backfilled with structural fill. These values are allowable values; a factor-of-safety of 1.5 has been included. As movement of the foundation elert�ent 1 is required to mobilize full passive resistance, the passive resistance should be neglected if � such movement is not acceptable. Unless covered by pavements or slabs, the passive resistance in the upper 1 foot of soil should be neglected. � ECI should be retained to observe the foundation subgrade prior to placement of structural fill, forms, or rebar. � Slab-on-Grade Floors I Slab-on-grade floors may be supported on competent native soil or structural fill. Loose or disturbed subgrade soil must either be compacted to the requirements of structural fill or replaced with structural fili. � Slabs should be provided with a capillary break comprised of a minimum of 4 inches of free- draining sand or gravel. In areas �+vhere slab moisture is undesirable, a vapor barrier, such as , a 6-mil plastic membrane, should be placed beneath the slab. � Retaining Walls Retaining walls should be desiyned to resist the lateral loads imposed by the retained soils � and applicable surcharge loads. � Walls that are designed to yieid can be designed to resist the lateral earth pressures imposed i by an equivalent fluid with a unit weight of 35 pcf. If walls are to be restrained at the top from � free movement, the equivalent iluid weight should be increased to 50 pcf. These values are based on horizontal backfill conditions. Surcharges due to backfill slopes, hydrostatic I pressures, traffic, structural loads, or other surcharge loads are assumed to not act on the wall. If such surcharges are to apply, they should be added to the above design lateral pressure. � For seismic design, a rectangular distribution equal to 7H psf, where H is the height of the wali, should be added to the earth pressure for yielding walls. The passive pressure, , allowable bearing capacity, and friction coefficient previously provided in the "Foundations" section are applicable to the retaining wali design. To reduce the potential for hydrostatic pressures to build up behind the walls, retaining walls � shouid be backfilled with a free-draining material extending at least 18 inches behind the wall. The free-draining backfill should consist of either pea gravel or washed rock. A rigid, 4- � inch-diameEer, schedule 4�, perforated PVC drain pipe shoufd be placed at the base of the i wall and should be surrounded by a minimum of 1 cubic foot per lineal foot with pea gravei or washed rock. The pipe should be placed with the perforations down. The remainder of the i backfill should consist of structural fill. � EARTH CONSUITNG INCORPORATED P;re;