1318 37TH ST 2018-01-02 MF Import

James Pirie JN 97072 March 10, 1997 Page 5 A one-third increase in the above design bearing pressures may be used when considering short- term wind or seismic loads. For the above design criteria, it is anticipated that the total post - construction settlement of footings founded on competent, native soil, or on structural fill up to 5 feet in thickness, will be about one-half inch, with differential settlements on the order of one-half inch in a distance of 50 feet along a continuous footing. Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the foundation. For ine latter condition, the foundation must be either poured directly against relatively level, undisturbed soil or surrounded by level, structural fill. We recommend using the following design values for the foundation's resistance to lateral loading: Parameter Design Value Coefficient of Friction 0.45 Passive Earth Pressure 350 pcf Where: 1, pcf is pounds per cubic foot. 2. Passive earth pressure is computed using the equivalent fluid density. If the ground in front of a foundation is loose or sloping, the passive earth pressure given above will not be appropriate, We recommend a safety factor of at least 1.5 for the foundation's resistance to lateral loading, when using the above design 4alues. Seismic Considerations The site is located within Seismic Zone 3, as illustrated on Figure No. 16-2 of the 1994 Uniform Building Code (UBC). In accordance with Table 16-J of the 1994 UBC, the site soil profile is best represented by Profile Type S2. The native soils that underlie the site are not susceptible to seismic liquefaction. Slabs -on -Grade The building floors may be constructed as slabs -on -grade atop competent, native soils or structural fill. The subgrade soil must be in a firm, non -yielding condition at the time of slab construction or underslab fill placement. Any soft areas encountered should be excavated and replaced with select, imported, structural fill. All slabs -on -grade should be underlain by a capillary break or drainage layer consisting of a minimum 4-inch thickness of coarse, free -draining, structural fill with a gradation similar to that discussed later in Permanent Foundation and Retaining Walls. In areas where the passage of moisture through the slab is undesirable, a vapor barrier, such as a 6-mil plastic membrane, should 6/20 GEOTECH CONSULTANTS, INC.