6301 36TH AVE W 2016-11-01 - Laserfiche WebLink

' June 23, 2014 Project No.T-6241 ' 5.4 Slopes and Embankments All permanent cut and fill slopes should be graded with a finished inclination of no greater than 2:1. Upon ' completion of grading, the slope face should be appropriately vegetated or provided with other physical means to guard against erosion. Final grades at the top of the slope must promote surface drainage away from the slope crest. Water must not be allowed to flow uncontrolled over the slope face. If surface runoff must be directed ' towards the slope, the runoff should be controlled at the top of the slope, piped in a closed conduit installed on the slope face,and taken to an appropriate point of discharge beyond the toe. ' All fill placed for embankment construction should meet the structural fill requirements in Section 5.2 of this report. In addition, if the new fills will be placed over existing slopes of 20 percent or greater, the structural fill should be keyed and benched into competent native slope soils. Figure 3 presents a typical slope key and bench ' configuration. At minimum, a toe drain should be installed in the key cut as shown on Figure 3. Depending on seepage ' conditions, drains may also be required along individual benches excavated on the slope face. The need for drains along the upper benches will be best determined in the field at the time of construction. 5.5 Foundations The buildings may be supported on conventional spread foundations bearing on properly prepared subgrades of ' competent native soil or structural fills placed above competent native soils. Foundation subgrades should be prepared as recommended in Section 5.2 of this report. Perimeter foundations exposed to the weather should be a minimum depth of 18 inches below final exterior grades. Interior foundations can be constructed at any convenient depth below the floor slab. We recommend designing foundations supported by competent medium dense to dense native soils or properly ' placed and compacted structural fill for a net allowable bearing capacity of 3,000 pounds per square foot (psf). For short-teen loads, such as wind and seismic,a one-third increase in this allowable capacity can be used. ' For designing foundations to resist lateral loads, a base friction coefficient of 0.35 can be used. Passive earth pressure acting on the sides of the footings may also be considered. We recommend calculating this lateral resistance using an equivalent fluid weight of 300 pounds per cubic foot (pcf). We recommend not including the ' upper 12 inches of soil in this computation because they can be affected by weather or disturbed by future grading activity. This value assumes the foundations will be constructed neat against competent native soil or the excavations are backfilled with structural fill, as described in Section 5.2 of this report. The recommended ' passive and friction values include a safety factor of 1.5. 5.6 Slab-on-Grade Floors ' Slab-on-grade floors may be supported on subgrade prepared as recommended in Section 5.2 of this report. Immediately below the floor slab, we recommend placing a four-inch thick capillary break layer composed of ' clean, coarse sand or fine gravel that has less than three percent passing the No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab. Page No. 9 1