4816 HARBOR LN 2016-01-01 MF Import

� Letter to Joe Johnston Project No. 9463-001 July 29, 2008 Page 5 Therefore, in summary, it is my opinion that the proposed enlarged replacement decks are not expected to provide adverse impacts to the steep slopr ':havior. And the risk of increased adverse behavior to new decks as related to the existin, Jecks is relatively insignificant. For the proposed replacement decks, I recommend that foundations be supported on finn glar,ially densified native bearing soils. The foundations could be designed with an allowable bearing pressure of 2,000 pounds per square foot (ps� when founded on the firm native soils free of organics and disturbed soils. This static allowable bearing pressure uses a factor of safety of 2.5 and is based on the following conditions: All footings should be founded into the firm native site soils below the root zone, as described above. 2. All footing excavations should be prepared such that a dense, nonyielding, uniform soil condition has been established prior to placement of footing concrete. 3. All footings should extend through any existing artificial fills or modified zones and be placed to bear a minimum of 18 inches below finished adjacent grade, or to a sufficient depth to establish an "effective setback". 4. All footings should be sized according to the anticipated wall or column loadings, and the above bearing values. Minimum footing widths of 16 and 20 inches are recommended for all continuous and isolated footings, respectively. 5. Ail footing areas should be free of ponded water and sloughed or water loosened soil prior to the placement of footing concrete. Ground settlement due to structural loads should be less than one (1) inch total and one-half (Y:) inch differential over the recommended footing area, depending on the care used in footing subgrade preparation. I recommend that footing areas be inspected by this office prior to piacement of concrete to verify that the type and condition of the bearing soils are consistent with the recommendatio�is of this letter. During earthwork to construci the addition foundations, care should be exercised to maintain stockpiies of excavated soils a minimum of 20 feet back from the top of the steep slope. When the addition is completed and backfilled, all excess excavated soils should preferably be removed from the site, or at least, relocated to thin landscaping fill on the lot as far to the east as feasible. J. KEITH CROSS, P.E. 6358 121°Avemie SE, Bellevue, Washington 98006-4425 �