6107 BERKSHIRE DR 2018-01-02 MF Import

ANPT Engi: peering, Inc. Western Wireless Corporation ADaPTJob No, WA98-992 April 1, 1998 Page 5 Footing Dimensions: We recommend that the thickened edge of the slab be designed as a sptead foating and be constructed to have a minimum width of 12 inches. For frost protection, the footings should penetrate at least 18 inches below the lowest adjacent exterior grades. Footings may be supported on structural fill placed on prepared native soil subgrade. The horizontal limits of the fill pad below the building foundation may be established by extending a line outwards from the base of the thickened slab at an angle of 1 Horizontal : I Vertical (I H:I V) down to the upper surface of the bearing horizon. Bearing Pressures: At the location of boring B-I, the near surticial soil should be stripped, excavated to a depth of at least 18 inches below the lowest adjacent glade, and compacted in place resulting in a film and unyielding subgrade condition. A maximum allowable soil bearing pressure of 2,000 (rounds per -square - foot can be used for static footing loads. This bearing pressure can be increased by one-tl:ird to accommodate transient wind or seismic loads. An allowable base friction r;oefficient of 0.40 and an allowable passive earth pressure of 350 pounds per cubic foot (pcf), expressed as an equivalent fluid unit weight, may be used for that portion of the foundation embedded more than 1 foot below finished exterior subgrade elevatiop Settlements: We estimate that total post -construction settlements of properly designed footings bearing on properly prepared subgrades could approach 1-inch, with differential settlements approaching one-half of the total. Tower Drilled Pier Foundalion.v Based upon the subsurface soil and groundwater conditions disclosed by our test boring, we recommend that the tower be supported on a drilled pier foundation. The following recommendations and comments are provided for purposes of drilled pier design and construction: Compressive Capacities: We recommend that the drilled pier penetrate at Icast 15 feet below the ground surface at the locati it of boring B-I. For vertical compressive soil bearing capacity, we recommend using the unit end be. -ring capacity presented in Table I below. The allowable end bearing capacity, preseptcd in Table I, includes a safety factor of 1.5 or more. We anticipate that adequate pier embedment for end bearing, uplift and lateral resistance can generally be obtained within the limits of our exploration of 29 feet.