10008 25TH AVE SE 2016-01-01 MF Import

� � � � � 3.4 FOUNDATION SUPPORT � For spread footings placed cn undisturbed native soil or properly placed and compacted structurnl � fill, we recommend using spread footing foundations with a minimum width of at least 18 inches. i � Foundations conswcted in this manner may be proportioned using a net ailowable maximum soil bearing i i pressure of 2,0�0 psf. The recommended allowable bearing capacity includes a factor of safety of at least ,� i 3.0 applied to the assumed frictional strength of the bearing s,il. The maximum allowable beariag capacity may be increased by one-third for short-tertn transient loads, such as wind and earthquakes. � Footings should bear at least 18 inches below any lowest adjacent external gade for frost protection. For foundations bearing on native soil or structural fill, total �ettlements should be less than 1 1 inch. Differential settlement, between adjacent foundation members, should be less than % inch. The majority of the settlements will occur during constniction as loads are applied. .-� Resistance to lateral loads may be assumed to be provided by friction acting on the base of footings and by passive laterel earth pressures acting against the sides of footings. M ultimate ccefiicient _.� of sliding resistance of 0.40, applied to the vertical dead loads only, may be used to compute frictional resistance. M allowable static passive lateral earth pressure of 250 pcf may be used for the sides of footings poured against undisturbed natural or recompacted soil where the soil surface is level for a , horizontal distance of at least twice the embedment depth. The upper I ft of passive resistance should be neglected in design if not covered by pavement. The value for ccetlicient of sliding resistance dces not linclude a factor of safety, and the vaiues for the passive earth pressure have been reduced by a factor of � 1.5 to limit det!ections to less than 2 percent of the embedded depth. I 3.5 FLOOR SLAB SUPPORT IThe floor slab may be supported by existing fill(if properly recompacted), undisturbed native soil or structunl fill, provided that the subgrade is properly prepared. Prior to placing the drainage blanket, � the upper 12 inches of the subgrade soil should be moisture conditioned to near optimum rnoisture conten!and thoroughly compacted to at least 95 percent of the maximum dry density(ASTM-D 1557). � A minimum of 4 inches of clean, free-draining material, such as nominal 5/8-inch minus washed gravel should be placed beneath slab-on-grade floors to act as a capillary break layer. It may be desirable ' to place a condensation barrier, such as visqueen or a membrane, beneath the slab-on-grade tloor to —1 prevent condensation of water vapor on the bottom of the floor slab and wicking up through the floor I slab. If a condensation barrier is installed beneath the floor slab, it should consist of a 10-mil membrane � with tape-sealed join�s. The American Concrete Institute (ACq guidelines recommend that 4 inches of � compacted granular fill, such as 5/8-inch minus crushed rock, be placed over the barrier to facilitate � LANOAUASSOCIATES � 5/,2&DI IV'ROJECT10��0050101EASTIAOM RPT.DOC 3-; I . __ -