5402 25TH AVE W 2016-01-01 MF Import

• • City of Everett � . . c/o Ron ard Kelly Krueger . August 22, 2007 , Page 3 The proposed structure can be supported on conventional continuous and spread footings bearing on undisturbed native soils or on structural fill placed above native soils. See the later sub-section entitled General Earthwork and Structural Fill for structural fill placement and compacti�n recommendations. Continuous and individual spread footings should have minimum widths of eighteen (18) and twenty-four(24) inches, respectively, and shculd be bottomed at least eighteen (18) inches below the lower adjacent finish ground surtace. Depending on the final site grades, some over-excavation may be required below footings to expose competent native soils. Unless lean concrete is used to fill the over excavated hole, the width of the over-excavation at the bottom must be at least as wide as the sum of two times the depth of the over-excavation and the footing width. For exaniple, an over-excavation extending two feet below the bottom of a three-foot wide footing must be at least seven feet wide at the base of the excavation. Footings constructed according to the above recommendations may be designed for an allowable soil bearing pressure of three thousand (3,0�0) pounds �er square foot (p.s.f.). A one-third increase in this design bearing pressure may be usea when considering short-term wind or seismic loads. For the above desi�n criteria, it is anticipated that total post-construction settlement of footings founded on competent, native soils (or on structural fill up to five (5) feet in thickness) will be about one-half inch, with differential r:ettlements on the order of one-quarter inch. Lateral loads due to wind or seismic forces may be resisted by fiction between the foundations and the bearing soils, or by passive earth pressure acting on the vertical, embedded portions o4 the foundations. For the latter condition, the foundations must either be poured directly against undisturbed soil or the bac�ll placed around the outside of the foundation must be level structural fill. We recommend the following design values be used for the foundation's resistance to lateral loading: Parameter Desiqn Value Coefficient of Friction 0.55 Passive Earth Pressure 350 p.c.f. Where: (1) p.c.f. is pounds per cubic foot. (2) Passive earth pressure is computed using the equivalent fluid density. We recommend that a safety factor of at least 1.5 be used for design of the foundation's resistance to lateral laading. � � a 3�L ;