6300 MERRILL CREEK PKY BASE FILE 2018-01-01 MF Import

Quadrant JN 97092 August 13, 1997 Page 4 An allowable bearing pressure of 2,500 pounds per square foot (ps� is appropriate for footings supported on competent, native soil or structural fill. A one-third increase in this design-bearing pressure may be used when considering short-tertn 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, will be about three-quarters inch, with differential settlements on the order of one-half inch in a distance of 100 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, embt�dded portions of the foundation. For the 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: Paremeter Design Value Coefficient of Friction I 0.50 ........._.._............................_.._...................._................�....__........_._._............... Passive Earth Pressure i 300 pcf Wlicru: (i) pcf Is Nounds pur cubic(ool,and(iq passivo oarlli prcssure Is computed using the aqulv�lent(luld density. If the ground in front of a foundation is loose or sloping, the passive earih 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 values. 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. There is not a potential for seismic liquefaction of the glacial till soil at this site. Slabs-on-Grade The building floors may be constructed as slabs-on-grade atop native giacial till 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 Retainins� Wails. If the 12-inch topping of pit-run gravel is used, this 4-inch layer is not needed. In areas where the passage of moisture through the slab is undesirable, a vapor barrier, such as a 6-mil plastic membrane, should be placed beneath the slab. Additionally, sand should be used in the fine-grading process to reduce damage to the vapor barrier, to provide uniform support under the slab, and to reduce shrinkage cracking by improving the concrete curing process. GEOTECN CONSULTANTS,INC.