6525 HARDESON RD BASE FILE 2016-01-01 MF Import

� Intracorp August 25, 1997 E-3592-710 Pape 2 With foundation support obtained as described, for design, an allowable bearing capacity of two thousand five hundred (2,500) psf can be used for continuous footings or structural fill. A bearing value of four thousand (4,000) psf may be used for spread footings. Continuous and individual spread footings should have minimum widths of efghteen (18) and twenty-four (24) inches, respectively. Loading of this magnitude would be provided with a theoreticalfactor-of-safety in excess of three sgainst actual shear failure, For short-term dynamic loading conditions, a one-third increase in the above allowable bearing capacities can be used. With structural loading as expected, total settlement in the range of one inch is anticipated with differential movement of about one-half inch. Most of the anticipated settlements shoutd occur during construction as dead loads are applied. 6'iF1s�LE : � : � � Slab-on-grade floors may be supported on competent native soil subgrade or on structural fill. Disturbed subgrade soil must either be recompactad or replaced with structural fill. Slab-on-grade floors should be designed by the structural engineer based on the anticipated loading and the subgrade support characteristics. A modulus of vertical subgrade reaction of two hundred (200) pounds per cubic inch (pci) may be used for design. Concrete siabs resting on soil ultimately cause the moisture content of the underlying soils to rise. This results from continued capillary rise and the ending of normal evapotranspiration. As concrete is permeable, moisture will eventually penetrate the slab resulting in a condition commonly known as a"wet slab" and poor adhesion of floor coverings. Therefore, the slab should be provided with a minimum of four inches of free-draining sand or gravei. In areas where slab moisture is undesirable, a vapor barrier such as a 6-mil plastic membrane may be placed beneath the slab. Two inches of damp sand may be placed over the membrane for protection during construction and to aid in curing of the concrete. Horizontal loads can be resisted by friction between the base of the foundation and the supporting soil and by passive soil pressure acting on the face of the buried portion of the foundation. For the latter, the foundation must be poured "neat" against the competent native soils or backfilled with structural fill. For frictional capacity, a coefficient of .40 Eerth Comuhents, Inc.