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Thomas Kelly JN 95192 <br /> June 7, 1995 Page 4 <br /> ��Ler ___ f2��i9n Value <br /> Coefficient of Friction 0.40 <br /> Passive Earth Pressure 200 pcf <br /> Where: <br /> (1) pcf is pounds per cubic foot. <br /> (2) Passive earth pressure is ccmputed using the <br /> equivalentfluid density. <br /> We recommend a safety factor of at least 1.5 for the foundation's resistance to lateral <br /> loading,when using the above design values. <br /> �ismic Considerations <br /> The site is located within Seismic Zone 3 as illustrated on Figure No. 23-2 of the 1991 <br /> Uniform Building Code (UBC). In accordance with Table 23-J of the 1991 UBC, the site soil <br /> protile is best represented by Profile Type S2. The sands are not subject to seismic <br /> liquefaction. <br /> SIab�9n_ rade <br /> The building floors may be constructed as slabs-on-grade atop native sands or structural fill. <br /> The subgrade soils must be in a firm, non-yielding condition at the time of slab construction <br /> or underslab fill placement. Any soft areas encountered should be excavated and replaced <br /> with select, imported, structural fill. <br /> A�i slabs-on-grade should be underlain by a capillary break or drainage layer consistiny of a <br /> minimum 4-inch thickness of coarse, free-draining, structural fii! with a gradation similar to <br /> that discussed later in Permanent Founcl�tion atld Reteipiflg Wa11s In areas where <br /> the pass��e of muisture through the slab is undesirable, z vapor barrfer, such as a 6-mil <br /> plastic membrane, should be placed beneath the slab. Additionally, sand should be used in <br /> the fine-grading process to reduce damage to the vapor barrier, to provide uniform support <br /> under the slab, and to reduce shrinkage cracking by improvi�g the concrete curing process. <br /> Isoiation joints shouid be provided where the slabs intersact columns and walls. Control <br /> and expa�ision joints should also be used to control cracking from expansion and <br /> contraction. Saw cuts or preformed strip joints used to control shrinkage crncking should <br /> extend through the upper one-fourth of the slab, The spacing of control or expansion joints <br /> cr.o•n:a t coNsui:rnN�s,iNc <br />